PHYSIOLOGY MIDTERM PDF - Questions & Answers

FINALLY QUESTIONS 1) The effects of sympathetic and parasympathetic fibers are cooperative in A. the digestive system B. the heart C. the eyes D. the reproductive system 2) All of the following are vital centers located the medulla oblongata except the A. cardiac control center B. vasomotor center C. reticular activating system center D respiratory center 3) Electrical synapses————- a occur when two cells are joined by integrin proteins b. occur between two cells of unequal size c. require the presence of gap junctions d. are characterized by a synaptic cleft 4) The specialized cells of the PNS that are surrounded by a basement membrane that is capable of forming a regeneration tube through which a severed peripheral axon can regrow are the a microglia b. oligodendrocytes c. astrocytes d. Schwann cells 5) Which of these is (are) found in the medulla oblongata? A. cardioregulatory center Flng question B. swallowing reflex center C. reflex center for vomiting D. reflex centers for sneezing and coughing E. all of these 6) A motor unit is a. the motor end plate where a nerve fiber synapses with a muscle fiber b. a sarcomere c. a spinal reflex arc d. one motor neuron and all muscle fibers to which it leads 7) Antidiuretic hormone (ADH) and oxytocin are synthesized by supraoptic and paraventricular nuclei, which are located in A. the pineal gland B. the thalamus C. the hypothalamus D. the pons 8) The consolidation of short-term memory into long-term memory appears to be a function of A. the substantia nigra B, the cerebral peduncles C. the precentral gyrus D. the hippocampus 9) In a single reflex arc involved in the knee-jerk reflex, how many synapses are activated within the spinal cord? A. One B. Two C. Thousands D. Hundreds 10) The pyramids are found in the A. pons B. diencephalon C. medulla oblongata D. midbrain E. cerebrum 11) The ＿is the structure of the CNS that filters sensory input, allowing only ~1% of sensory information to reach the cerebrum A. Cerebellum B. thalamus C. Medulla oblongata D. pons 12) The ＿＿ seems to be involved in converting short-term memories Into long-term memory. A. basal nuclei, including the corpus striatum and the lentiform nucleus B. prefrontal cortex C. left medial temporal lobe, including the hippocampus and the amygdaloid nucleus D. Wernicke's area 13) Which neuron does releases a catecholamine as a neurotransmitter? A. Postganglionic parasympathetic fibers B. Postganglionic sympathetic fibers C. Preganglionic parasympathetic fibers D. Preganglionic sympathetic fibers 14) The pyramids of the medulla oblongata are the sites of A decussation of nerve tracts B. the regulation of speech C. origin of cranial nerves IX-XII D. respiratory, cardiac, and vasomotor control 15) The nervous system must monitor the behavior of muscies. The receptor that provides information about the amount of tension being exerted on a given tendon is the a. gamma motoneuron b. extrafusal fiber c. muscle spindle d. Golgi tendon organ 16) In most people, the right hemisphere controls movement of A. both the right and left sides of the body equally B. the head and neck only C, the right side of the body primarily D the left side of the body primarily 17) Which of these statements about the medulla oblongata is false? A. It contains the vasomotor center B. It contains ascending and descending fiber tracts C. It contains nuclei for some cranial nerves D. It contains the apneustic center 18) Which of the following statements about parasympathetic neurons is true? A. They synapse in terminal ganglia, either next to or within the organs innervated B. The nerve fibers are contained in spinal nerves C. They originate in thoracic and lumbar regions of the spinal cord D. Postganglionic tbers are usually longer than those of sympathetic neurons. 19) The conduction of action potentials in a myelinated nerve fiber is a. saltatory b. faster than in an unmyelinated fiber c. without decrement d. all answers are correct 20) The ridges on the surface of the cerebrum are called A gyri B. sulci C. fissures D. tracts 21) The production and release of lactate to provide energy to the neurons is a function of the a. oligodendrocytes b. Schwann cells c. astrocytes d. microglia 22) The cell bodies of sensory fibers from the neck down are found in the A. dorsal root B. ventral horn C. ventral root D. dorsal root ganglion 23) Impulses from the cochlea of the ear are transmitted to what part of the brain? A. The occipital lobe B. The temporal lobe C. The parietal lobe D. The hippocampus 24) Antidiuretic hormone (ADH) and oxytocin are synthesized by supraoptic and paraventricular nuclei, which are located in A. The pituitary gland B. The hypothalamus C. The thalamus D. The pineal gland 25) The pons includes all of the following except the A. pneumotaxic center B. cardiac control center C. nuclei where some cranial nerves originate D. nerve fibers transmittting information to the cerebellum 26) Parasympathetic ganglia are located : A. in a chain parallel to the spinal cord B. next to or within the organs innervated C. in the brain D. in the dorsal roots of spinal nerves 27) Sensations from the skin are received by what part of the brain? A. The precentral gyrus B. Wernicke's area ° C. The postcentral gyrus D. The amygdale 28) The spinal cord originates at the medulla oblongata and terminates in the A sacrum B. first lumbar vertebra C. The spinal cord originates at the medulla obiongata and terminates in the D. соссух 29) Most nerve fibers of the pyramidal tracts of the spinal cord originate in the A. precentral gyrus B. thalamus C. midbrain D. pyramids of the medulla oblongata 30) Which of the following target tissues is innervated by only neurons from the sympathetic nervous system? A. bronchioles B. adrenal medulla C. iris of the eye D. lacrimal glands 31) The two subtypes of cholinergic receptors are A. adrenergic and nicotinic B. dopaminergic and muscarinic C. nicotinio and dopaminergic D. nicotinic and muscarinic 32) Alcohol depresses the activity of neurons associated with the maintenance of balance, which are located in what part of the CNS? A. cerebrum B. Cerebellum C. Medulla oblongata D. thalamus 33) All sensory input into the brain is filtered except sensory input from A. heat receptors B. pain receptors C. smell chemoreceptors D touch, mechanical receptors 34) Coordinates voluntary movement and balance A. pituitary gland B. thalamus C. cerebellum D. hippocampus 35) The structure of the brain responsible for conscious thought, intellect, memory storage and processing, controlling the movement of skeletal muscies, and sensation is the a. cerebellum b. thalamus c. cerebrum d. Medulla oblongata 36) Atropine blocks parasympathetic nerve effects. It would therefore cause A. decreased movements of the digestive tract B. all of these C. Increased heart rate D. dilation of the pupils 37) The brain area that most directly controls the activity of the autonomic nervous system, is the A. medulla oblongata B. pitultary gland C. hypothalamus D. Cerebellum 38) A structure in the limbic system linked to memory A. cerebellum B. thalamus C. hippocampus D. pituitary gland 39) The junction between a nerve and a muscle is called a a. neurotransmitter b. synapse c. neuromuscular junction d. sarcomere 40) Which of these structures is NOT part of the brainstem? A. cerebellum B. pons C. medulla oblongata D. midbrain 41) when a visceral organ is denervated C. It becomes hypersensitive to subsequent stimulation 42) Parasympathetic ganglia are located C. Next to or within innervated 43) The neurotransmitter of preganglionic sympathetic fibers is C. Acetylcholine 44) which of these results from stimulation of alpha-adrenergic receptors? A. Constriction of blood vessels 45) which of these fibers release norepinephrine? C. Postganglionic sympathetic fibers in the heart 46) propranolol is a beta blocker. It would therefore cause B. Slowing of the heart rate 47) Atropine blocks Parasympathetic nerve effects. It would therefore cause A. Dilation of the pupils B. Decreased mucous secretion C. Decreased movements of the digestive tract D. Increased heart rate E. All of the above 48) which area of the brain is most directly involved in the reflex control of the autonomic system? C. Medulla oblongata 49) the two subtypes of cholinergic receptors are C. Nicotinic and muscarinic 50) which of the following is an important inhibitory neurotransmitter that keeps emotion and behavior under control? B. Gamma - aminobutyric acid (GABA) 51) The——— plays a major role in the regulation and control of emotions. C. Limbic system 52) which of the following parts of the brain is primarily concerned with the coordination and regulation of muscular activity? B. The occipital lobe 53) coordinating body movements and posture and helping maintain body equilibrium are the major functions of the—— B. Cerebellum 54) which of the following statements is true of the basal ganglia? B. The basal ganglia help regulate skeletal muscle activity 55) Degeneration of the neurons in the basal ganglia leads to——- B. Parkinson’s disease 56) The——is a collection of the nerve axons that travel to and from the brain C. Spinal cord 57) Which of the following is true of the location of the medulla oblongata? B. It lies just above the spinal cord 58) The axons of the efferent neurons transmit nerve impulses carrying information associated with all of the following except A. Pain 59) The pituitary gland is attached to the——- B. Hypothalamus 60) the two main components of the central nervous system are C. The brain and the spinal cord 61) Identify a difference between the cerebral cortex and the basal ganglia. B. The cerebral cortex perceives all sensory sensations and initiates all voluntary muscle movements, whereas the basal ganglia help coordinate and regulate muscular activity 62) all of the following types of nerve impulses are carried by the axons of afferent neurons except D. Nerve impulse for directing organ activity 63) Identify a function of the pons A. It serves as a relay station for nerve fibers traveling to other brain areas 64) which of the following structures does the diencephalon include? D. The thalamus 65) Which of the following statements is true of the central nervous system (CNS) ? A. The primary functions of the CNS are to coordinate and control the activity of other body systems. 66) The——is referred to as the master gland of the body. B. Pituitary gland 67) The pituitary gland is closely associated with which structure of the brain? D. Hypothalamus 68) All of the following are vital centers within the medulla oblongata except A. The thermoregulatory center 69) Which part of the brain does a medication for a gambling addiction need to affect? B. The limbic system 70) Which part of a person’s brain is activated when he or she is choking on a piece of steak? D. Medulla oblongata 71) A reduction in membrane potential is the definition of which term? B. Depolarization 72) The oligodendrocyte E. Forms myelin in the CNS 73) During the rising phase of an action potential, voltage- gated D. Sodium channels open 74) exocytosis of neurotransmitter into the synaptic cleft is triggered by an influx of —— in response to the arrival of an action potential in the axon terminal A) Calcium 75) of the following choices, which is the only structure that is in the central nervous system? D. Basal nuclei 76) The only type of neuron whose cell bodies always lie outside the CNS is D. Unipolar 77) The ventricles of the brain and the central canal of the spinal cord are lined with. C. Ependymal cells 78) A nerve A. is a cablelike bundle of parallel axons 79) To separate the brainstem from the forebrain, a cut must be made between the. C. Midbrain and diencephalon 80) The pyramids are——-nerve tracts that are involved in the conscious control of—— E. Descending, skeletal muscle 81) The corpora quadrigemina are found in the D. Midbrain 82) The superior colliculi are involved with —— whereas the inferior colliculi are involved with——- E. Visual reflexes, hearing and auditory reflexes 83) In the midbrain, descending tracts going from the cerebrum to the spinal cord are called the A. Cerebral peduncles 84) Which of these structures contains the intermediate mass? C. Thalamus 85) the pineal body is found in the C. Epithalamus 86) the cerebrum is divided into right and left hemispheres by the D. Longitudinal fissure 87) the primary motor cortex is located in the D. Precentral gyrus of the frontal lobe 88) the ——— lobe of the cerebrum is the major center for the reception and evaluation of sensory information, except for smell, hearing, and vision D. Parietal 89) Cerebrospinal fluid passes into the blood by way of the A. arachnoid granulations 90) which of these spaces contains cerebrospinal fluid? E. All of these 91) A drooping upper eyelid could indicate damage to cranial nerve C. III (Oculomotor) 92) Which of these cranial nerves carriers Parasympathetic fibers to the thoracic and abdominal organs? D. X (vagus) 93) The fibrous connective tissue sheath which encloses a whole muscle is called the C. Epimysium 94) The contraction strength of a whole muscle varies in accordance with the A. Number of motor units activated 95) contraction in a muscle occurs because the C. The filaments slide between the thick filaments 96) the thick filaments of muscle are composed of D. Myosin 97) The ability to hydrolyze ATP during muscle contraction is due to the fact that A. Myosin contains an ATPase 98) The ability of myosin to interact with actin is regulated by the binding of A. Ca2+ to troponin 99) The thin filaments of a muscle fiber consist of all of the following except B. Myosin 100) when a muscle lengthens as it contracts, this type of contraction is known as a(n) C. Eccentric contraction 101) the calcium that binds to troponin to activate muscle contraction comes from storage sites located in the D. Sarcoplasmic reticulum 102) Excitation- contraction coupling refers especially to the C. Calcium release and binding to troponin molecules 103) Terminal cisternae of the sarcoplasmic reticulum release Ca2+ when signaled by the C. T tubules 104) In skeletal muscle contraction Ca2+ must bind to troponin for contraction to occur and in order for the muscle to relax the Ca2+ must C. be actively transported into the sarcoplasmic reticulum 105) As opposed to the upper motor neurons, the lower motor neurons have their cell bodies located in the C. Spinal cord as opposed to the brain 106) Slow- twitch muscle fibers B. Are very resistant to fatigue 107) The Ca2+ required for sustained contraction of smooth muscle fibers comes mainly from the A. Extracellular fluid surrounding the fibers 108) Myosin light - chain kinase D. is antagonized by the actions of myosin phosphatase 109) A motor neuron and its associated myofibers is called a B. Motor unit 110) Skeletal muscle is connected to bones by B. Tendons 111) what is the neurotransmitter released at the motor end plate? D. Acetylcholine 112) which of these statements about precentral gyrus is true? A. It’s involved in motor control B. It’s involved in sensory perception C. It’s located in the frontal D. Both A and C are true 113) In most people, the right hemisphere controls movement of B. The left side of the body primarily 114) which of these acts as a relay center for somatesthetic sensation? A. Thalamus 115) The consolidation of declarative memory requires the——-, Working memory requires the—— B. Medial temporal lobe, prefrontal cortex 116) The reticular activating system E. Is described correctly by all of these 117) In the control of emotion and motivation, the limbic system works together with C. Hypothalamus 118) The hormone primarily responsible for setting the basal metabolic rate and for promoting the maturation of the brain is D. Thyroxine 119) Which of these hormones uses cAMP as a second messenger? D. Epinephrine 120) Which of these terms best describes the interactions of insulin and glycogen? C. Antagonist 121) Which of these correctly describes the role of inositol triphosphate in hormone action ? B. It stimulates the release of Ca2+ from the endoplasmic reticulum 122) Which of these hormones may have a primary role in many circadian rhythms? D. Melatonin 123) Which of these muscles have motor units with the highest innervation ratio? C. Muscles that move the fingers 124) The stimulation of gamma motoneurons produces C. isometric contraction of intrafusal fibers 125) Electrical excitation of a muscle fiber most directly causes C. Release of Ca2+ from the sarcoplasmic reticulum 126) The energy for muscle contraction is most directly obtained from B. ATP 127) when a muscle is stimulated to contract, Ca2+ binds to D. Troponin 128) Which of these muscle types is striated and contains gap junctions? C. Cardiac muscle 129) Which of the following statements is not characteristic of smooth muscle? A. myosin phosphatase is required for contraction 130) Which of the following is not a nucleus within the hypothalamus? A. Red nucleus 131) Which of the following are not found in the midbrain? C. Cerebral nuclei 132) the structures in the brain that comprise the limbic system are involved in——- B. Goal- directed behaviors 133) the cerebrum is divided into five lobes, including all of the following except the…… B. Sagittal 134) The right and left cerebral hemispheres are connected to each other mainly by a bundle of nerve fibers called the——— D. Corpus callosum 135) the gray matter of the brain constitutes primarily the…….portion of the brain A. Cortex 136) The central cavities in the brain that are filled with cerebrospinal fluid are known as…… C. Ventricles 137) The….layer of the embryo gives rise to the tissues of the nervous system A. Ectoderm MIDTERM QUESTIONS The absolute refractory period of a neuron a. occurs only during the depolarization phase b. occurs only during the repolarization phase c. occurs during depolarization and the first part of the repolarization phase. d. is due to the high negative polarity of the inside of the neuron. Repolarization of an axon during an action potential is produced by a. inward diffusion of NA+. b. active extrusion of K+. c. outward diffusion of K+. d. inward active transport of Na+ Depolarization of an axon is produced by a. inward diffusion of NA+. b. active diffusion of K+. c. outward diffusion of K+ d. inward active transport of Na+ 11) Absolute refractory period is caused by: a. Inactivation of Ca2+ channels b. Inactivation of Na+ channels c. Slow closure of K+ channels d. Slow opening of Na+ channels 12) The first voltage-regulated gates encountered along the neuron membrane, which initiate the formation of action potentials, are located on the neuron near the a. Postsynaptic membrane of the dendrite b. Axon hillock c. Cell body d. Axon terminal 13) Within the central nervous system astrocytes are responsible for a. aid in synapse formation b. producing cerebrospinal fluid c. phagocytizing particulate matter d. myelinating axons 14) In neuromuscular junction small quanta (packets) of acetylcholine are released randomly from the nerve cell membrane at rest, they produce. a. action potential b. miniature end plate potential c. slow postsynaptic potential d. IPSP 15) Which of the following is a consequence of myelination in large nerve fibers? a. Increased nonselective diffusion of lons across the axon membrane b. Increased energy requirement to maintain ion gradients c. Decreased velocity of nerve impulses d. Generation of action potentials only at the nodes of Ranvier 16) Which of the following decreases in length during the contraction of a skeletal muscle fiber? a. M band of the sarcomere b. A band of the sarcomere c. I band of the sarcomere d. Z discs of the sarcomere 17) Electrical excitation of a muscle fiber most directly causes a. splitting of ATP b. movement of tropomyosin c. release of Ca 2 + from the sarcoplasmic reticulum d. attachment of the cross bridges to action 18) Which of these neurons are pseudounipolar? a. Neurons in the retina b. Sensory neurons c. Autonomic motor neurons d. Somatic motor neurons 19) Which of the following statements about excitatory postsynaptic potentials (EPSPs) is correct? a can be produced by an increase in Ca2+ conductance b can be produced by a decrease in Na+ conductance c. move the membrane potential of the postsynaptic neuron away from the firing level 20) Which of the following statements about action potential is false? a. Signal intensity can change amplitude of action potential b. Na+/K+ ATPase establishes electrochemical gradient c. After reaching critical level, voltage-gate Na+ channels open d. A decrease in extracellular Ca2+ increases cellexcitability Which one of the following nerves has the slowest conduction velocity? a. C fibers b. B fibers c. A alpha fibers d. A beta fibers e. A gamma fibers Excitation- contraction coupling in skeletal muscle involves all the following events except a. ATP hydrolysis b. Binding of Ca2+ to calmodulin c. Depolarization of the transverse tubule (T tubule) membrane d. Increased Na+ conductance of sarcolemma Which of these statements about homeostasis is true? a. The internal environment is maintained absolutely constant b Negative feedback mechanisms act to correct deviations from a normal range within the internal environment c. Homeostasis is maintained by turning effectors on and off d. All of these are true A group of nerve fibers (axons) within the CNS a. a nucieus b. a nerve c. a tract d. a ganglion The nervous system must monitor the behavior of muscles. The receptor that provides information about the amount of tension being exerted on a given tendon is the a. extrafusal fiber b. muscle spindle c. Golgi tendon organ d. gamma motoneuran Which of the following is not characteristic of presynaptic inhibition? a. The axon of a second neuron synapses with the axon (rather than the dendrite) of the original neuron b. The first neuron is partially depolarized by the release of a neurotransmitter from the second neuron c. Lesser amounts of a neurotransmitter is released by a neuron due to a second neuron that reduces the number of action potentials arriving at the original neuron terminal d. The second neuron axon has a direct inhibitory effect on the original neuron axón Which second messenger promotes bronchconstriction? A. cGMP B. IP3 C. CAMP D. Calmodulin The threshold of cell membrane excitability is most directly controlled by A. Potassium B. Chloride C. Calcium D. Sodium Each of the following interventions drives K+ into cells EXCEPT: A. Administering sodium bicarbonate B. Administering calcium gluconate C. Hyperventilating the lungs D. Administering insulin-glucose Following a fracture and casting for prolonged period muscle is significantly smaller in circumference than prior to the fracture. What is the most likely explanation? A. decrease in the number of individual muscle fibers B. decrease in blood flow to the muscle caused by constriction from the cast C. temporary reduction in actin and myosin protein synthesis D. increase in glycolytic activity in the affected muscle E. progressive denervation The force produced by a single skeletal muscle fiber can be increased by which of the following? A. decreasing extracellular K+ concentration B. increasing the amplitude of the depolarizing stimulus C. increasing the frequency of stimulation of the fiber D. increasing the number of voltage-gated Na+ channels in the sarcolemma E. increasing the permeability of the sarcolemma to K+ ATP is used directly for each of the following processes EXCEPT one. Which one is this EXCEPTION? A. accumulation of Ca++ by the sarcoplasmic reticulu B. transport of glucose into muscle cells C. transport of H+ from the parietal cells into the lumen of the stomach D. transport of K+ from the extracellular to intracellular fluid E. transport of Na+ from the intracellular to extracellular fluid The delayed onset and prolonged duration of smooth muscle contraction, as well as the greater force generated by smooth muscle compared with skeletal muscle, are all consequences of which of the following? A. greater amount of myosin filaments present in smooth muscle B. higher energy requirements of smooth muscle C. physical arrangement of actin and myosin filaments D. slower cycling rate of the smooth muscle myosin cross bridges E. slower uptake of Ca++ ions following contraction Which of the following is primarily responsible for the change in membrane potential between the peak of the action potential and the fall? A. inhibition of the Na+, K+ - ATPase B. movement of K+ into the cell C. movement of K+ out of the cell D. movement of Na+ into the cell E. movement of Na+ out of the cell Which of the following is primarily responsible for the change in membrane potential between the threshold and the peak of the action potential? A. inhibition of the Na+, K - ATPase B. movement of K+ into the cell C. movement of K+ out of the cell D. Movement of Na+ into the cell E. Movement of Na+ out of the cell Weightlifting can result in dramatic increase in skeletal muscle mass. This increase in muscle mass is primarily attributable to which of the following? A. fusion of sarcomeres between adjacent myofibrils B. hypertrophy of individual muscle fibers C. increase in skeletal muscle blood supply D. increase in the number of motor neurons E. increase in the number of neuromuscular junctions Tetanic contraction of a skeletal muscle fiber results from a cumulative increase in the intracellular concentration of which of the following? A. ATP B. Ca++ C. K+ D. Na+ E. Troponin A cross-sectional view of a skeletal muscle fiber through the H zone would reveal the presence of what? A. actin and titin B. actin, but no myosin C. actin, myosin, and titin D. myosin and actin E. myosin, but no actin In a normal, healthy muscle, what occurs as a result of propagation of an action potential to the terminal membrane of a motor neuron? A. opening of voltage-gated Ca++ channels in the presynaptic membrane B. depolarization of the T tubule membrane follows C. always results in muscle contraction D. increase in intracellular Ca++ concentration in the motor neuron terminal E. all of the above are correct Calmodulin is most closely related, both structurally and functionally, to which of the following proteins? A. G-actin B. Myosin light chain C. Tropomyosin D. Troponin C A single contraction of skeletal muscle is most likely to be terminated by which of the following actions? A. closure of the postsynaptic nicotinic acetylcholine receptor B. removal of acetylcholine from the neuromuscular junction C. removal of Ca++ from the terminal of the motor neuron D. removal of sarcoplasmic Ca++ E. return of the dihydropyridine receptor to its resting conformation What is occurring when the length-tension of a single vertebrate striated muscle fiber is maximized? A. actin filaments are overlapping each other B. myosin filaments are overlapping each other C. the Z discs of the sarcomere abut the ends of the myosin filament D. there is optimal overlapping between the actin and myosin filaments E. there is minimal overlap between the actin and myosin filaments Which of the following decreases in length during the contraction of a skeletal muscle fiber? A. A band of the sarcomere B. I band of the sarcomere C. thick filaments D. thin filaments E. Z discs of the sarcomere Excitation-contraction coupling in skeletal muscle involves all of the following events EXCEPT: A. ATP hydrolysis B. binding of Ca++ to calmodulin C. conformational change in dihydropyridine receptor D. depolarization of the transverse tubule (T tubule) membrane E. increased Na+ conductance of sarcolemma Which of these may be produced by the action of nitric oxide? a. Dilation of blood vessels. b. Erection of the penis. c. Relaxation of smooth muscles in the digestive tract. d. Long term potentiation(LTP) among neighboring synapses in the brain. e. All of these Hyperpolarization is caused by all of these neurotransmitters except a. glutamic acid in the CNS. b. ACh in the heart. c. glycine in the spinal cord. d. GABA in the brain Which of these statements about ACh receptors is false? a. Skeletal muscles contain nicotinic ACh receptors. b. The heart contains muscarinic ACh receptors. c. G-proteins are needed to open ion channels for nicotinic receptors. d. Stimulation of nicotinic receptors results in the production of EPSPs The summation of EPSPs from numerous presynaptic nerve fibers converging onto one postsynaptic neuron is called a. spatial summation. b. long-term potentiation. c. temporal summation. d. synaptic plasticity Which of these statements about catecholamines is false? a. They include norepinephrine, epinephrine, and dopamine. b. Their effects are increased by action of the enzyme catechol-O-methyltransferase. c. They are inactivated by monoamine oxidase. d. They are inactivate by reuptake into the presynaptic axon. e. They may stimulate the production of cyclic AMP in the postsynaptic axon Hyperpolarization of the postsynaptic membrane in response to glycine or GABA is produced by the opening of a. Na+ channels. b. K+ channels. c. Ca+ channels. d. Cl- channels Postsynaptic inhibition is produced by a. depolarization of the postsynaptic membrane. b. hyperpolarization of the postsynaptic membrane. c. axoaxonic synapses. d. long term potentiation A drug that inactivates acetylcholinesterase a. inhibits the release of ACh from presynaptic endings. b. inhibits the attachments of ACh to its receptor proteins. c. increases the ability of ACh to stimulate postsynaptic contraction. d. does all of these Which of these is not a characteristic of action potentials? a. They are produced by voltage- regulated gates. b. They are conducted without decrement. c. Na+ and K+ gates open at the same time. d. The membrane potential reverses polarity during depolarization Which of these is not a characteristic of synaptic potentials? a. They are all or none in amplitude. b. They decrease in amplitude with distance. c. They are produced in dendrites and cell bodies. d. They are graded in amplitude. e. They are produced by chemically regulated gates The conduction of action potentials in myelinatec nerve fiber is a. saltatory. b. without decrement. c. faster than in an unmyelinated fiber. d. all of these As the stregnth of a depolarizing stimulus to an axon is increased, a.the amplitude of action potentials increases. b. the duration of action potential increases. c. the speed with which action potentials are conducted increases. d. the frequency with which action potentials are produced increases Which of these neurons are pseudounipolar? a. sensory neurons. b. Somatic motor neurons. c. Neurons in the retina. d. Autonomic motor neuron A collection of neuron cell bodies located outside the CNS is called a. a tract. b. a nerve. c. a nucleus. d. a ganglion The supporting cells that form myelin sheaths in the PNS(peripheral nervous system) are a. oligodendrocytes. b. satellite cells. c. Schwann cells. d. astrocytes. e. microglia The resting potential of a myelinated nerve fiber is primarily dependent on the concentration gradient of which of the following ions? A)Ca++ B)Cl- C)HCO3- D)K+ E)Na+ A clinical study is conducted to determine the actions of an unknown test solution on red blood cell volume. One milliliter of heparinized human blood is pipetted into 100 milliliters of test solution and mixed. Samples are taken and analyzed immediately before and at l- second intervals after mixing. The results show that red blood cells placed into the test solution immediately swell and burst. Which of the following best describes the tonicity and osmolarity of the test solution? A) Hypertonic; could be hyperosmotic, hypo-osmotic, or iso-osmotic B) Hypertonic; must be hyperosmotic or hypo-osmotic C) Hypertonic; must be iso-osmotic D) Hypotonic; could be hyperosmotic, hypo-osmotic, or iso-osmotic E) Hypotonic; must be hyperosmotic or hypo-osmotic F) Hypotonic; must be iso-osmotic What is the osmolarity of a solution containing 10 millimolar NaCl, 5 millimolar KCl, and 10 millimolar CaCl2 (in mOsm/L)? A)20 B)40 C)60 D)80 E)100 Simple diffusion and facilitated diffusion share which of the following characteristics? A) Can be blocked by specific inhibitors B) Do not require adenosine triphosphate (ATP) C) Require transport protein D)Saturation kinetics E) Transport solute against concentration gradient Which of these consists of dense parallel arrangement of collagen fibers? a. skeletal muscle tissue b. nerve tissue c. tendons d. dermis of the skin Which of these statements about homeostasis is true? a. the internal environment is maintained absolutely constant b. negative feedback mechanisms act to correct deviations from a normal range within the internal environment c. homeostasis is maintained by turning effectors on and off d. all of these are true Myosin light-chain kinase ＿ a. is activated by cAMP b. phosphorylates myosin to regulate muscle contraction in cardiac muscle c. phosphorylates myosin to stimulate relaxation in smooth muscle d. is antagonized by the actions of myosin phosphatase A person continues breathing heavily for some time after exercising in order to "repay an oxygen debt". This oxygen debt includes all of the following except the oxygen that was ＿ a. taken from hemoglobin in the blood b. taken from myoglobin in the muscle c. needed to replenish the store of glycogen in the muscle d. needed to metabolize the lactic acid produced by exercise The cerebral nuclei normally inhibit lower motor neurons. Therefore, damage to the cerebral nuclei can cause a. clonus b. paraplegia c. intention tremor d. chorea The sensitivity of muscle spindles to stretch can be adjusted by ＿＿ a. further stretching of the extrafusal fibers b. alpha motoneurons c. gamma motoneurons d. annulospiral nerve endings As opposed to the upper motor neurons, the lower motor neurons have their cell bodies located in the a. thalamus as opposed to the cerebral cortex b. medulla oblongata as opposed to higher brain centers c. spinal cord as opposed to the brain d. lumbar and sacral regions as opposed to cervical and thoracic Terminal cisternae of the sarcoplasmic reticulum release Ca2+ when signaled by the ＿ a. motor end plate b. sarcomeres c. T tubules d. motor nerve fibers ATP is required by two different processes that are necessary for the contraction and relaxation of a muscle. One is the interaction between thick and thin filaments of the sarcomeres and the other is the a. binding of acetylcholine to the motor end plate b. release of calcium from the sarcoplasmic reticulum c. movement of the troponin-tropomyosin complex d. reuptake of calcium by the sarcoplasmic reticulum. If a muscle is already at about 80% of its resting length, it cannot be stimulated to contract any more because ＿ a. there is no more ATP b. the myosin cross bridges cannot reach the actin filaments c. the Z lines abut against the thick filaments and cannot go any further d. muscle fibers obey the all-or-none law Rigor mortis in a corpse results from the fact that a. all of the neurotransmitter is used up b. all of the calcium ions are used up c. thick filaments cannot let go of the thin filaments without ATP d. motor neurons can no longer function At what stage in the cross-bridge cycle is ATP split into ADP and Pi? a. Before the cross bridges of myosin can attach to actin. b. During the power stroke when the myosin cross bridge flexes. c. At the end of the power stroke before myosin lets go of the actin filament. d. At the end of the power stroke after myosin lets go. During contraction the … a. actin filaments bind to the myosin cross bridges b. I bands lengthen c. sarcomeres do not change in length d. size of the H zone increases A muscle is stimulated and exhibits a contraction (twitch). Before this twitch is over, it is stimulated again, and a second twitch occurs "piggyback" on the first one and causes a higher contraction strength. This phenomenon is called ＿ a. incomplete tetanus b. graded contraction c. summation d. complete tetanus Suppose you are sitting in the middle of a sofa and move both of your hands to your stomach. This action of the arms is known as ＿＿ a. extension b. abduction c. adduction d. flexion Name the molecule that binds calcium ions and causes smooth muscle to contract. a. tropomyosin b. calmodulin c. troponin d. G-actin The region of the resting sarcomere where the thin and thick filaments are overlapping is seen in the a. lighter region of the I bands b. dark color of the I bands c. narrow dark line known as the Z line d. dark color of the A bands Sustained muscle activity may consume ATP faster than aerobic respiration can produce it. In such circumstances, ATP can be made by combining ADP with phosphate groups borrowed from ＿ a. creatine kinase b. phosphocreatine c. cyclic AMP d. phospholipids ATP is required by two different processes that are necessary for the contraction and relaxation of a muscle. One is the interaction between thick and thin filaments of the sarcomeres and the other is the a. movement of the troponin-tropomyosin complex b. release of calcium from the sarcoplasmic reticulum c. binding of acetylcholine to the motor end plate d. reuptake of calcium by the sarcoplasmic reticulum The ability of myosin to interact with actin is regulated by the binding of … a. Ca2+ to troponin b. ATP to actin c. Ca2+ to tropomyosin d. titin to ATP As opposed to the upper motor neurons, the lower motor neurons have their cell bodies located in the a. thalamus as opposed to the cerebral cortex b. spinal cord as opposed to the brain c. lumbar and sacral regions as opposed to cervical and thoracic d. medulla oblongata as opposed to higher brain centers If a muscle is already at about 80% of its resting length, it cannot be stimulated to contract any more because ＿ a. the myosin cross bridges cannot reach the actin filaments b. muscle fibers obey the all-or-none law c. there is no more ATP d. the Z lines abut against the thick filaments and cannot go any further Myosin light-chain kinase ＿ a. phosphorylates myosin to regulate muscle contraction in cardiac muscle b. is activated by CAMP c. is antagonized by the actions of myosin phosphatase d. phosphorylates myosin to stimulate relaxation in smooth muscle Terminal cisternae of the sarcoplasmic reticulum release Ca2+ when signaled by the ＿ a. motor end plate b. T tubules c. motor nerve fibers d. sarcomeres Which of the following is not a factor in muscle fatigue? A) a drop in intracellular pH B) accumulation of lactic acid C) production of IPSPs by motor neurons D) accumulation of extracellular K+ Slow twitch muscle fibers ＿ A) have a relatively low oxidative capacity B) are very resistant to fatigue C) have a high glycogen content D) have a high myosin ATPase content Sustained muscle activity may consume ATP faster than aerobic respiration can produce it. In such circumstances, ATP can be made by combining ADP with phosphate groups borrowed from … A) creatine kinase B) phosphocreatine C) cyclic AMP D) phospholipids The nervous system must monitor the behavior of muscles. The receptor that provides information about the amount of tension being exerted on a given tendon is the … A) extrafusal fiber B) Golgi tendon organ C) gamma motoneuron D) muscle spindle Excitation-contraction coupling refers especially to the ＿ A) means by which electrical excitation of a muscle results in muscle contraction B) propagation of action potentials from the neuromuscular junction to the T tubules C) calcium release and binding to troponin molecules D) attachment of myosin cross bridges to the thin filaments The Ca2+ that binds to troponin to activate muscle contraction comes from the storage sites located in the ＿ A) transverse tubules B) extracellular fluid C) synaptic vesicles of the motor neuron D) sarcoplasmic reticulum The basic unit of muscle contraction is the sarcomere, which is ＿ A) one A band and the adjacent I band B) the distance from one Z line to the next C) equivalent to a fascicle of muscle fibers D) equivalent to one of the myofibrils within a muscle fiber The thick filaments of muscle fibers are composed of ＿ A) tropomyosin B) troponin C) actin D) myosin The region of the resting sarcomere where the thin and thick filaments are overlapping is seen in the A) narrow dark line known as the Z line B) dark color of the I bands C) lighter region of the I bands D) dark color of the A bands Contraction in a muscle occurs because the A) thin filaments get shorter B) thick filaments get shorter C) thin filaments slide between the thick filaments D) titin proteins pull on opposite ends of the sarcomere A motor unit is ＿ A) the motor end plate where a nerve fiber synapses with a muscle fiber B) one motor neuron and all muscle fibers that it innervates C) a spinal reflex arc D) a sarcomere If enough muscle fibers contract to make the muscle as a whole shorten in length, the muscle is said to exhibit ＿＿ contractions. A) concentric B) eccentric C) isometric Skeletal muscle cells are striated, that is they have alternating dark and light bands called … respectively. A) A and I bands B) H and M bands C) Z and M lines D) I and H bands Within a muscle, the fibers are divided into larger bundles called ＿, each surrounded by its own connective tissue sheath. A) sarcomeres B) sarcolemma C) myofibers D) fascicles The fibrous connective tissue sheath, which encloses a whole muscle, is called the ＿ A) endomysium B) perimysium C) epimysium D) sarcolemma Abductor and adductor muscles make up pairs that together are called … A) antagonistic B) agonistic C) complementary D) permissive When a skeletal muscle contracts, it usually moves the bone at one end much more than the bone at its other end. The attachment of the muscle to the less moveable bone is called its. A) ligament B) insertion C) flexor D) origin Which of the following is not characteristic of presynaptic inhibition? A) The axon of a second neuron synapses with the axon (rather than the dendrite) of the original neuron. B) The second neuron axon has a direct inhibitory effect on the original neuron axon. C) The first neuron is partially depolarized by the release of a neurotransmitter from the second neuron. D) Lesser amounts of a neurotransmitter is released by a neuron due to a second neuron that reduces the number of action potentials arriving at the original neuron terminal. EPSPs produced by many different presynaptic fibers converging on a single postsynaptic neuron, cuasing summation on the postsynaptic dendrites and cell body, best describes A) synaptic plasticity B) temporal summation C) synaptic inhibition D) spacial summation The most prevalent brain neurotransmitter, produced by as many as one third of all neurons in the brain, is A) ACh B) NE C) seratonin D) GABA Which of the following neurotransmitters is inhibitory, causing chloride channels to open in the post synaptic membrane and forming IPSPs? A) glycine B) asparic acid C) norepinephrine D) glutamic acid Drugs known as amphetamines stimulate neural pathways causing mental arousal and PNS effects that duplicate sympathetic nerve activation. The neurotransmitter that amphetamines mimic in this way, is A) acetylcholine B) norepinephrine C) serotonin D) dopamine Parkinson's disease is caused by the loss of neurons that secreate the neurotransmitter A) acetylcholine B) noepinephrine C) seratonin D) dopamine Adenylate cyclase is an important enzyme that A) inhibits cAMP by converting it into inactive metabolites B) phosphorylates other proteins to open postsynaptic membrane channels C) converts ATP to cAMP and pyrophosphate into the postsnaptic cell cytoplasm D) catalyzes the conversion of ADP and phosphate to activate ATP All of the following regulatory molecules are neurotransmitters in the chemical family known as monoamines, except A) acytelcholine B) epinephrine D) dopamine D) seratonin The first voltage regulated gates encountered along the neuron membrane, which initiate the formation of action potentials, are located on the neuron near the A) post synaptic membrane of the dendrite B) cell body C) axon hillock D) axon terminal Which of the following statements about excitatory postsynaptic potentials (EPSP), is false? A) EPSPs have summation, an all or none event, and a refractory period B) EPSPs open sodium and potassium gates upon stimulation C( EPSPs are inhibited by the drug curare, but not by tetrodotoxin D) EPSPs open ion gates when stimulated by ACh Acetylcholinesterase is an enzyme located on or immediately outside the A) presynaptic membrane B) post synaptic membrane C) axon terminal cytoplasm D) vesicles released by exocytosis Which of the following statements best describe nicotinic ACh receptors as opposed to muscarinic ACh receptors? A) nicotinic receptors have only a single subunit, binding to one molecule B) nicotinic receptors activate G-protein complexes located in the cell membrane. C) nicotinic receptors do not contain an ion channel D) nicotinic receptors are closed until ACh molecules bind to the receptor proteins Which of the following is not a property of chemically regulated gates? A) they respond best to membrane potential changes, such as depolarization B) they are located on the post synaptic membrane C) they may allow Na+ and K+ diffusion through ion channels simultaneously D) they are activated by neurotransmitters binding to specific receptor molecules All of these neurons release ACh as a neurotransmitter except A) specific CNS neuron endings B) somatic motor neurons at the neuromuscular junction C) specific autonomic neuron endings, excitatory or inhibitory D) specific cardiac and smooth muscle fibers Which statement about chemically regulated (or ligand regulated) gates is false? A) they open in response to chemical changes in the postsynaptic cell membrane B) once opened, ion flow can depolarize or hyperpolarize the membrane C) they contain receptor proteins that recognize and bind with a specific ligand D) they are found in the axons and open in response to depolarization When the neurotransmitter molecules released from the presynaptic axon terminals have diffused across the synaptic celft and have reached the postsynaptic membrane, they A) activate electrical synapses or gap junctions B) open voltage-regulated Ca2+ channels promoting the influx of calcium ions C) bind to specific receptor proteins opening chemically regulated ion channels D) are absorbed by endocytosis into the postsynaptic membrane and reutilized The ion that must flow into the presynaptic neuron ending through voltage-regulated channels to activate the release of neurotransmitter chemicals from synaptic vesicles is A) sodium B) potassium C) calcium D) iron As the intensity of the stimulus in a presynaptic neuron increases, the number of vesicles undergoing exocytosis ＿＿, and the number of released neurotransmitter molecules ＿ A) increases;increases B) increases;decreases C) decreases;increases D) decreases;decreases The small membrane-enclosed compartments that hold and release the neurotransmitter molecules from within the presynaptic neuron are called A) synaptic vesicles B) synaptic clefts C) terminal boutons D) gap junctions Nerve impulses (action potentials) conducted along a neorn axon without decrement means they are conducted without A) decreasing its velocity B) altering the threshold potential C) decreasing its amplitude D) altering the Na+ or K+ concentrations in the neuron During the absolute refractory period along an axon membrane of a neuron, A) the potassium gates are open and K+ is diffusing down its concentration gradient. B) the sodium gates are closed and Na+ is is diffusing down the concentration gradient C) the neuron is unable to respond to stimulus of any intensity D) the membrane is most sensitive to stimuli When a greater stimulus strength is applied to a neuron A) identical action potentials are produced more frequently B) the total amplitude of each action potential increases also C) the neuron fires a steady barrage of action potentials for a longer duration of time Both the depolarization and repolarization changes that occur during the action potential are produced by A) simple diffusion of ions down their concentration gradients B) active transport pumps along the neuron membrane C) negative feedback loops D) carrier mediated transport Diffusion of K+ out of the cell makes the inside of the cell less positive, or more negative, and acts to restore the original resting membrane potential - a process called A) depolarization B) hyperpolarization C) repolarization D) overshoot Which statements about the action potential or nerve impulse is false? A) only a relatively small number of NA+ and K+ ions actually diffuse across the membrane B) this event includes both positive and negative feedback loops C) the Na+/K+ pumps are directly involved in creating the action potential D) During an action potential that Na+ and K+ total concentrations are not significantly changed Arrange these action potential events in their proper sequence: 1. threshold voltage is reached 2. K+ gates begin to open 3. K+ gates close 4. NA+ gates begin to open 5. NA+ gates begin to close 6+ membrane repolarization begins A) 1, 2, 4, 3, 5, 6 B) 4, 6, 3, 2, 1, 5 C) 4, 6, 2, 1, 5, 3 D) 1, 4, 2, 5, 6, 3 The term "Voltage regulated" means that the membrane A) gated ion channels open and close with changes in the membrane potential B) potential is controlled by the NA+/K+ pumps C) gates will not respond unless the voltage is "regular" D) potential can only be controlled by an oscilloscope When a neuron is stimulated there is an inward flow of positive charges into the cell causing the line recorded on an oscilloscope to A) move upward away from the resting potential and toward zero B) move downward toward the resting potential away from zero C) stay constant at the resting potential D) oscillate up and down in a wave-like fashion All cells in the body maintain a potential difference (voltage) across the membrane called the ＿ , in which the inside of the cell is negatively charged in comparison to the outside of the cell. A) Action potential B) threshold potential C) resting potential D) graded potential The ＿ are large, star-shaped cells with numerous cytoplasmic processes radiating outward. They take up potassium ions from the extracellular fluid and also release glutamine, an important raw molecule for neurons. A) microglia B) astrocytes C) oligodendrocytes D) satellite cells The specialized cells in the CNS that are surrounded by a basement membrane that is capable of forming a regeneration tube through which severed peripheral axon can regrow are the ＿? A) schwann cells B) oligodendrocytes C) microglia D) astrocytes The nervous system supporting cell (neurogli) that has both amoeboid properties to permit migration through the CNS and phagocytosis properties to remove foreign and degenerated material from the CNS tissue, is the A) schwann cells B) satellite cells C) oligodendrocytes D) microglia The glial cell in the CNS, which forms perivascular efet and is associated with the blood-brain barrier, is the A) astrocyte B) oligodendrocyte C) satellite cell D) microglia Which of the following cell types is not a supporting cell or glial cel of the nervous system? A) Schwann cell B) oligodendrocyte C) astrocyte D) association neuron Myelin sheaths around axons located within the CNS are formed by A) schwann cells B) microglia C) astrocytes D) oligodendrocytes Structurally, the most common type of neuron, such as a motor neuron, composed of several dendrites and one axon extending from the cell body, is the ＿ neuron. A) bipolar B) multipolar C) pseudounipolar Involuntary effectors are innervated (stimulated by) A) autonomic neurons B) efferent neurons C) motor neurons D) association neurons A ＿ neuron transmit impulses out of the CNS to an effector organ such as a muscle or a gland. A) association B) sensory C) motor D) ganglion The origin of the axon near the cell body is an expanded region where nerve impulses originate and is known as the A) axon B) axon hillock C) axon collateral D) dendrite A grouping of cell bodies located within the PNS is known as a A) tract B) nerve C) nucleus D) ganglion Which of the following is not a function of neurons? A) respond to physical and chemical stimuli B) conduct electrical impulses C) release specific chemical regulators D) all of these are neuron functions Regarding synaptic cell activation A) summation of post synaptic potentials may be related to the timing of neurotransmitter release B) summation of post synaptic potentials may be related to the site of neurotransmitter release C) summation may involve both inhibitory and excitatory postsynaptic potentials D) all of the above Blocking reuptake of dopamine would induce effects similar to A) Parkinson's disease B) multiple sclerosis C) cocaine use D) Alzheimer's disease Postsynaptic potentials A) always induce action potentials B) lack refractory periods C) are always excitatory D) are always inhibitory Muscarinic receptors A) require the action of G-proteins B) are found on skeletal muscle C) are functionally linked to Sodium ion channels. D) all of the above. At a chemical synapse A) acetyl choline is always an excitatory neurotransmitter in the autonomic nervous system. B) phosphorylation of synapsins stimulates neurotransmitter release. C) repolarization of the axon terminal allows Calcium to flow into the axon terminal. D) neurotransmitters are transported across the synapse by receptor proteins. Which of the following is not true of an action potential? A) action potentials follow the all-or-none law. B) positive feedback is important during depolarization. C) negative feedback is important during repolarization. D) all cells in the body can produce action potentials. Opening only sodium ion channels in a neuron at rest would normally cuase A) hyperpolarization B) depolarization C) repolarization D) no change in membrane potential The blood-brain barrier would be compromised by damaging A) astrocytes. B) ependymal cells. C) microglia. D) oligodendrocytes. Which of the following neurons are found entirely within the central nervous system? A) Association neuron. B) Efferent neuron. C) Motor neuron. D) Sensory neuron Cocain stimulates the synapses of specific neurons that release dopamine and other monoamines by＿ a. inhibiting enzyme inactivation of dopamine or monoamine b. blocking the dopamine or monamine reuptake into the presynaptic axon ending c. mimicking the effects of dopamine or monamines on the postsynaptic cell d. facilitating the release of dopamine or monoamine from the presynaptic terminal Which of the following statements about EPSPs is false? a. EPSPs are all-or-none events b. EPSPs may result from the opening of Na+ gates upon stimulation c. EPSPs at nicotinic ACh synapses are inhibited by the drug curare but not by tetrodotoxin d. acetylcholine opens ion gates that produce EPSPs Acetylcoline is an enzyme located on or immediately outside the ??? a. presynaptic membrane b. postsynaptic membrane c. axon terminal cytoplasm d. vesicles released by exocytosis Electrical synapses a. occur when two cells are joined by integrin proteins b. are characterized by a synaptic cleft c. occur between two cells of unequal size d. require the presence of gap junctions Which of the following is not a neuron- neuron synapse??? a. neuromusclular junction b. axosomatic synapse c. axoaxonic synapse d. dendrodendritic synapse Myelin sheaths around axons located within the CNS are formed by a. schwann cells b. microglia c. astrocytes d. oligodendrocytes a＿ neuron transmits impulses from the periphery to the CNS a. association b. sensory c. motor d. ganglion The numerous small extensions from the soma are known as the a. axons b. axon hillocks c. axon collaterals d. dendrites A grouping of cell bodies located within the central nervous system is known as a. tract b. nerve c. nucleus d. ganglion A neuron generally has all of the following principle areas except a. microvilli b. cell body c. dendrites d. an axon Benzodiazepines have sedative properties because they a. keep GABA receptors open longer than normal. b. close GABA receptors. c. keep GABA receptors open more frequently. d. inhibit the reuptake of glutamate. When an action potential arrives at the synaptic ending, there is an increase in the ＿ concentration of calcium at the synaptic ending. The increased diffusion of this ion across the cell membrane is produced by the opening of a ＿ gate. a. extracellular, voltage-regulated b. intracellular, voltage-regulated c. extracellular, chemically-regulated d. intracellular, chemically-regulated The velocity of an axon potential across an axon will be greatest in which type of axon? a. myelinated, thin b. myelinated, thick c. unmyelinated, thin d. unmyelinated, thick Along the myelinated sections between nodes in a myelinated axon, electrical signals are conducted by a. active transport. b. saltatory conduction. c. cable properties. d. neurotransmitters. What is the name of the time period during the course of an action potential when no degree of depolarization can initiate another action potential? a. relative refractory period b. absolute refractory period c. overshoot d. threshold The neural mechanism that may represent a form of "learning" when transmission along frequently used nerve pathways results in improved efficiency of synaptic transmission, is called a. long-term potentiation. b. synaptic inhibition. c. presynaptic inhibition. d. synaptic plasticity. Which of the following statements about nitric oxide (NO) is false? a. NO acts locally to relax the smooth muscles of blood vessels. b. NO is occasionally used by dentists as an anesthetic. c. NO acts as a neurotransmitter of certain neurons in both the PNS and CNS. d. NO stimulates the production of cyclic guanosine monophosphate (cGMP). Which of the following is not a brain neurotransmitter that may have opioid (pain relieving) properties? a. enkaphalin peptides. b. dynorphin polypeptides. c. B-endorphins. d. catecholamines. The neurotransmitter that appears to be involved in diseases that affect the motor control of muscles, such as Huntington's chorea, status epilepticus (seizures), and perhaps, severe alterations in mood and emotions, is known as a. actylcholine. b. norepinephrine. c. serotonin. d. GABA. ＿ is/are lipid-like compound(s) produced by the brain that are believed to act as analgesics. a. Carbon monoxide b. Neuropeptide Y. c. Endorphins. d. Endocannabinoids Activation of protein kinase by cyclic adenosine monophosphate in response to norepinephrine results in a. degradation of norepinephrine by converting it into inactive metabolites. b. phosphorylation of other proteins that open postsynaptic membrane channels and have other effects in the postsynaptic cell. c. activation of phosphodiesterase. d. catalyzes the conversion of ADP and phosphate to active ATP. Myasthenia gravis is a disease producing muscle weakness caused by a. immune system antibodies that block and destroy acetylcholine receptors. b. blocking the release of acetylcholine from presynaptic vesicles. c. enhancing the breakdown of acetylcholine by acetylcholinesterase. d. blocking the flow of Na+ through open ion channels. Curare reduces the size of end plate potentials on the membrane of muscle fibers by a. competing with acetylcholine for attachment to the postsynaptic receptor proteins. b. blocking the release of acetylcholine from presynaptic vesicles. c. enhancing the breakdown of acetylcholine by acetylcholinesterase. d. blocking the flow of Na+ through open ion channels. All of these neurons release acetylcholine as a neurotransmitter except a. specific CNS neuron endings. b. somatic motor neurons at the neuromuscular junction. c. specific autonomic neuron endings, may be either excitatory or inhibitory. d. specific cardiac and smooth muscle fibers. If a neurotransmitter binds to a receptor on the target cell and produces depolarizations, the neurotransmitter a. was probably stimulating the flow of K+ ions out of the cell. b. produced an excitatory postsynaptic potential. c. produced an inhibitory postsynaptic potential. d. was probably stimulating the flow of Cl- ions into the cell. Which of the following statements about the conduction velocity of action potentials along myelinated axons as compared to that along unmyelinated axons, is false? a. Conduction velocity is very fast, approaching 225 miles per hour. b. Cable properties within the axon help increase the conduction velocity. c. Nodes of Ranvier increase the conduction velocity by saltatory conduction. d. Thinner fibers conduct action potentials faster than thicker fibers. As the intensity of stimulation increases, more and more nerve fibers will become activated -a process called a. frequency modulation. b. amplitude modulation. c. cable properties of the neuron. d. recruitment. If a resting neuron is stimulated and there is an inward flow of negative charges into the cell, the line recorded on an oscilloscope will a. move upward away from the resting potential and toward zero. b. move downward away from the resting potential away from zero. c. stay constant at the resting potential. d. oscillate up and down in a wave-like fashion. In the absence of stimuli, all cells in the body maintain a potential difference across the membrane called the ＿, in which the inside of the cell is negatively charged in comparison to the outside of the cell. a. action potential b. threshold potential c. resting membrane potential d. graded potential The production and release of lactate to provide energy to the neurons is a function of the a. microglia. b. astrocytes. c. oligodendrocytes. d. satellite cells. In the developing fetal nervous system, development of the sensory neurons requires the actions of a. glial-derived neurotropic factor. b. neurotrophin-3. c. neurtrophin-4. d. neurotrophin-5. Within the central nervous system astrocytes are responsible for a. myelinateing axons. b. producing cerebrospinal fluid. c. phagocytizing particulate matter d. aid in synapse formation. The glial cells in the CNS which are capable of phagocytosis are a. astrocytes. b. oligodendrocytes. c. satellite cells. d. microglia. Structurally, the type of neurons that act as sensory neurons are the ＿ neurons. a. bipolar b. multipolar c. pseudounipolar Densely staining areas or Nissl bodies of the cell body are composed of a. mitochondria. b. rough endoplasmic reticulum. c. Golgi apparatus. d. microfilaments and microtubules. Which cranial nerve supplies motor innervation to the superior oblique muscle of the eye? A. Trochlear B. Oculomotor C. Abducens D. Trigeminal What nerve provides motor innervation to the tongue? A. Vagus B. Hypoglossal C. Facial D. Trigeminal The cell bodies (soma) of which of the following structures lie in brainstem and sacral cord areas? A. Postganglionic sympathetic nerves B. Preganglionic sympathetic nerves C. Postganglionic parasympathetic nerves D. Preganglionic parasympathetic nerves Proprioception is carried by A. A-alpha fibers B. A-gamma fibers C. A-delta fibers D. dC fibers The effects of norepinephrine released from sympathetic postganglionic neurons are terminated mainly by A. Metabolism by MAO in the synaptic cleft B. metabolism by COMT in the synaptic cleft C. diffusion from the synaptic cleft into the blood stream D. Reuptake by the nerve terminal One reason the neonate needs more succinylcholine than the adult is because A. plasma cholinesterase activity is greater in the neonate B. renal clearance is slower in the neonate C. the neonate has more adipose tissue D. the motor end-plate of the neuromuscular junction is immature in the neonate A pure phospholipid bilayer is most permeable to which of the following? a. Water b. Sodium c. Calcium d. Oxygen Which of the following is not usually associated with positive feedback? a. Generation of nerve signals b. Amplification c. Reinforcing feedback d. Vicious cycles e. Homeostatic "control systems" The diagram shows the length-tension relationshp for a single sarcomere. Why is the tension development maximal between points B and C? A) Actin filaments are overlapping each other B) Myosin filaments are overlapping each other C) The myosin filament is at its minimal length D) The Z discs of the sarcomere abut the ends of the myosin filament E) There is optimal overlap between the actin and myosin filaments Which of the following statements about smooth muscle contraction is most accurate? A) Ca++ independent B) Does not require an action potential C) Requires more energy compared to skeletal muscle D) Shorter in duration compared to skeletal muscle Which of the following best describes an attribute of visceral smooth muscle not shared by skeletal muscle? A) Contraction is ATP dependent B) Contracts in response to stretch C) Does not contain actin filaments D) High rate of cross-bridge cycling E) Low maximal force of contraction Calmodulin is most closely related, both structurally and functionally, to which of the following proteins? A) G-actin B) Myosin light chain C) Tropomyosin D) Troponin C Which of the following is a consequence of myelination in large nerve fibers? A) Decreased velocity of nerve impulses B) Generation of action potentials only at the nodes of Ranvier C) Increased energy requirement to maintain ion gradients D) Increased membrane capacitance E) Increased nonselective diffusion of ions across the axon membrane Similarities between smooth and cardiac muscle include which of the following? A) Ability to contract in the absence of an action potential B) Dependence of contraction on Ca++ ions C) Presence of a T tubule network D) Role of myosin kinase in muscle contraction E) Striated arrangement of the actin and myosin filaments Which of the following transport mechanisms is not rate limited by an intrinsic Vmax? A) Facilitated diffusion via carrier proteins B) Primary active transport via carrier proteins C) Secondary co-transport D) Secondary counter-transport E) Simple diffusion through protein channels Which of the following is primarily responsible for the changes in membrane potential between points B and D? A) Inhibition of the Na+, K+ATPase B) Movement of K+ into the cell C) Movement of K+ out of the cell D) Movement of Na+ into the cell E) Movement of Na+ out of the cell Which of the following is primarily responsible for the change in membrane potential between points D and E? A) Inhibition of the Na+, K+ATPase B) Movement of K+ into the cell C) Movement of K+ out of the cell D) Movement of Na+ into the cell E) Movement of Na+ out of the cell The sarcoplasmic reticulum stores ＿ when a muscle is relaxed and releases it for binding to ＿＿ during contraction. a. calcium; troponin b. calcium; tropomyosin c. sodium; tropomyosin d. potassium; tropomyosin e. sodium; troponin The T tubules a. store Ca2+ b. provide a means of rapidly transmitting the action potential from the surface into the central portions of the muscle fiber c. store ATP d. run longitudinally between the myofibrils e. have expanded lateral sacs Sequence the following events involved in muscle cell contraction: 1. Sodium channels open and sodium flows in. 2. Impulse reaches the axon's terminal. 3. ACh binds to receptors on the muscle cell membrane. 4. Synaptic vesicles fuse with neuron's membrane and release ACh via exocytosis. 5. If enough sodium moves in to the muscle cell, an impulse (action potential) develops. Answer; 2,4, 3, 1, 5 According to the sliding-filament mechanism, the a. A bands slide between the I bands b. thin filaments slide inward toward the center of the A band c. Z lines slide between the T tubules d. contractile proteins shorten, thus shortening the sarcomere e. filaments slide past the lateral sacs of the sarcoplasmic reticulum Troponin a. binds with calcium to allow sarcomere shortening b. breaks down myosin cross bridges c. is an enzyme in the sarcomere d. forms the boundaries of a sarcomere e. has an ATPase site Identify the characteristic(s) shared by all types of muscle tissues? a. They are neurogenic. b. They have T tubules. c. They have tropomyosin. d. They attach to tendons. e. They have neuromuscular junctions. The functional unit of skeletal muscle a. is the smallest contractile component of a muscle fiber b. is the area between two Z lines c. is the sarcomere d. contains only one A band e. exhibits all of the above characteristics Order the following muscle cell components from larger to smaller: 1. troponin 2. myofibril 3. sarcomere 4. thin filament 5. muscle fiber Answer: 5, 2, 3, 4, 1 What happens when two or more overlapping action potentials are "added" together within a muscle? a. twitch fatigue b. twitch summation c. contraction addition d. contraction paralysis e. sarcoplasmic reduction which of the following is/are associated with skeletal muscle activity a. Somatic nervous system b. Sympathetic nervous system c. Motor neurons in the spinal cord d. All of the above are correct e. Only a and c above are correct Acetylcholinesterase a. has enhanced activity from organophosphates b. inactivates a neurotransmitter, ACh c. is a neurotransmitter d. stimulates an EPSP e. triggers the release of sodium from postsynaptic cells What is the fate of ACh following binding to receptors? a. It remains bound, causing continued excitement. b. It is removed by acetylcholinesterase. c. It is actively reabsorbed by the axon terminal. d. It is passively reabsorbed by the muscle cell. e. None of the above. At the neuromuscular junction, acetylcholine binds to what receptors? a. muscarinic receptors b. nicotinic receptors c. alpha-adrenergic receptors d. beta-adrenergic receptors The neuromuscular junction a. is the junction between a motor neuron and a skeletal muscle fiber b. Displays an excitatory activity by generating graded potentials called EPP c. may produce either an EPSP or an IPSP on the motor end plate d. has all of the above characteristics e. has characteristics a and b Skeletal Muscle: a. voluntary, neurogenic, and striated b. involuntary, myogenic, and striated c. involuntary, neurogenic and nonstriated d. involuntary, myogenic, and nonstriated During an isotonic contraction, a. sarcomeres do not shorten in the muscle b. movement does not occur inside the muscle c. the muscle does not change length d. the muscle's tension does not overcome a load e. the muscle's tension remains constant The regulation of smooth muscle contraction is mediated by the phosphorylation of ＿ in response to calcium binding to … a. myosin; calmodulin b. actin; calmodulin c. troponin; calmodulin d. myosin; troponin e. actin; troponin What are the two types of fast-twitch muscle fibers? a. oxidative and phosphoric b. oxidative and glycolytic c. pyruvic and glycolytic d. acetic and glycolytic e. fast and slow For effective control of motor output, what 2 types of muscle proprioceptors are needed by the CNS? a. muscle spindles and Golgi tendon organs b. muscle spindles and stretch receptors c. sarcoplasmic reticulum and Golgi tendon organs d. sarcomeres and Golgi tendon organs e. sarcomeres and stretch receptors When a muscle atrophies, its muscle fibers a. split lengthwise b. decreases in mass and becomes weaker c. increase in diameter d. undergo mitotic cell division e. dissolve and are replaced by fibrous scar tissue What is the first source for supplying additional ATP when exercise begins? a. oxidative phosphorylation b. glycolysis c. lactate d. creatine phosphate Each I band in a skeletal muscle fiber includes a. overlapping thin and thick filaments b. thick filaments and one Z disc c. thin filaments and one Z disc d. thin filaments and two Z discs e. actin, troponin, tropomyosin and two Z discs A motor unit refers to: a. a single motor neuron plus all of the muscle fibers it innervates b. a single muscle fiber plus all of the motor neurons that innervate it c. all of the motor neurons supplying a single muscle d. a pair of antagonistic muscles e. a sheet of smooth muscle cells connected by gap junctions Which statement is not true about cross bridges? a. They are a component of thin filaments. b. They are comprised of myosin. c. They have an actin binding site. d. They have an ATPase binding site. e. They provide power stroking. Which of the following statements about the Ca+ release channels in the sarcoplasmic reticulum is false? a. They are also called ryanodine receptors. b. They are one-tenth the size of the voltage-gated Ca+ channels. c. They are opened by Ca+ release channels in the transverse tubules. d. They permit Ca+ to diffuse into the sarcoplasm from the sarcoplasmic reticulum. Which of the following is an example of an eccentric muscle contraction? a. Doing a "curl" with a dumbbell. b. Doing a breast stroke in a swimming pool. c Extending the arms when bench-pressing a weight. d. Flexing the arms when bench-pressing to allow the weight to return to the chest. In an isotonic muscle contraction, a. the length of the muscle remains constant. b. the muscle tension remains constant. c. both muscle length and tension are changed. d. movement of bones does not occur. Which of these statements about muscle fatigue is false? a. It may result when ATP is no longer available for the cross-bridge cycle. b. It may be caused by a loss of muscle cell Ca+. c. It may be caused by the accumulation of extracellular K+. d. It may be the result of lactic acid production. When a muscle is stimulated to contract, Ca+ binds to a. myosin. b. tropomyosin. c. actin. d. troponin. Which of these statements about cross bridges is false? a. They are comprised of myosin. b. They bind to ATP after they detach from actin. c. They contain an ATPase. d. They split ATP before they attach to actin The energy for muscle contraction is most directly obtained from a. phosphocreatine. b. ATP. c. anaerobic respiration. d. aerobic respiration. When does a skeletal muscle shorten during contraction, which of these statements is false? a. The A bands shorten. b. The H bands shorten. c. The I bands shorten. d. The sarcomeres shorten. Spastic paralysis may occur when there is damage to a. the lower motor neurons. b. the upper motor neurons. c. either the lower or upper motor neurons. In a single reflex arc involved in the knee jerk reflex, how many synapses are activated within the spinal cord? a. Thousands. b. Hundreds. c. Dozens. d. Two. e. One The stimulation of gamma motoneurons produces a. isotonic contraction of intrafusal fibers. b. isometric contraction of intrafusal fibers. c. either isotonic or isometric contraction of intrafusal fibers. d. contraction of extrafusal fibers. Which of these muscles have motor units with the highest innervation ratio? a. Leg muscles. b. Arm muscles. c. Muscles that move the fingers. d. Muscles of the trunk. The series-elastic component of muscle contraction is responsible for a. increased muscle shortening to successive twitches. b. a time delay between contraction and shortening. c. the lengthening of muscle after contraction has ceased. d. all of these. A graded whole muscle contraction is produced in vivo primarily by variations in a. the strength of the fiber's contraction. b. the number of fibers that are contracting. c. both of these. d. neither of these. The contractile portion of the thin filament is composed of what protein? A) myosin B) tropomyosin C) troponin D) actin E) titin The fundamental repeating unit of the myofibril called a ________ gives skeletal muscle its striated appearance, and is bordered by ________. A) crossbridge : Z lines B) sarcomere : M lines C) sarcomere : I bands D) sarcomere : Z lines E) crossbridge : A bands What is the protein component of the thin filament that binds to calcium thereby initiating skeletal muscle contraction? A) myosin B) tropomyosin C) troponin D) actin E) titin The shortening of a skeletal muscle fiber during contraction involves which of the following? A) the thick filaments shortening B) the thin filaments shortening C) the sarcomeres shortening D) the A bands shortening E) the Z lines not changing their position The repeated, oscillating interaction between actin and myosin that results in the generation of force by a skeletal muscle cell is called what? A) crossbridge cycling B) the sliding-filament model C) Z line interaction D) sarcomeric facilitation E) titin cycling What converts the myosin head into the high-energy state? A) binding to ATP only B) binding to actin C) the condensation of ATP D) the hydrolysis of ATP E) binding to titin The release of an inorganic phosphate from the myosin molecule directly results in which of the following? A) development of rigor B) power stroke C) cocking of the myosin head D) binding of actin to myosin E) breaking of the actin myosin complex In order for crossbridge cycling to occur, the actin-myosin complex must be broken by which of the following? A) binding of tropomyosin to myosin B) binding of ATP to actin C) binding of the troponin complex to actin D) conformational change that occurs as the myosin head changes from the high to low energy state E) binding of ATP to myosin The sequence of events that links the action potential to changes in skeletal muscle force development is called what? A) the sliding-filament model B) crossbridge cycling C) myoaction coupling D) excitation-contraction coupling E) oxidative phosphorylation During skeletal muscle contraction, multiple crossbridge cycles are occurring between the same thick and thin filament. Which of the following best describes this process? A) Crossbridge cycling is highly synchronized between a certain thick and thin filament. B) Crossbridge cycling is asynchronous between a certain thick and thin filament. C) No more than one myosin head links to the thin filament at the same time. D) No more than one myosin head detaches from the thin filament at the same time. E) Tropomyosin only exposes one binding site on actin at a time allowing only one crossbridge to form with actin at a given time. Contraction of skeletal muscle fibers is stimulated by what type of neuron? A) autonomic neurons B) sympathetic neurons C) motor neurons D) parasympathetic neurons E) afferent neurons The binding of calcium to troponin will directly cause which of the following? A) the binding of ATP to myosin B) the further release of calcium into the cytoplasm C) the movement of tropomyosin, thereby exposing the myosin-binding site on the actin molecule D) the movement of tropomyosin, thereby exposing the actin-binding site on the myosin molecule E) the hydrolysis of ATP What portion of a sarcomere shows up as light striations when viewed under a microscope? A) A band B) I band C) H zone D) M line E) Z line During the cross-bridge cycle, ATP binding to myosin causes which of the following? A) the myosin head to attach to actin B) the myosin head to detach from actin C) the myosin head to swing forward pulling actin toward the M line D) the myosin head to interact with calcium channels, triggering calcium release from the sarcoplasmic reticulum E) the myosin head to be in its high-energy form Which of the following is NOT a specialization observed at the neuromuscular junction? A) the high density of acetylcholine receptors in the motor end plate B) Every action potential that reaches the axon terminal of the motor neuron will generate an action potential in the muscle fiber. C) The motor end plate is relatively large compared with other synapses. D) The terminal bouton fans out over a wide area of the sarcolemma. E) Each muscle fiber is innervated by multiple motor neurons. Increases in the amount of cytoplasmic calcium required to initiate a muscle contraction are mediated by the coupling between a ________ on the T tubule and a ________ on the membrane of the sarcoplasmic reticulum. A) dihydropyridine receptor : calcium pump B) dihydropyridine receptor : ryanodine receptor C) ryanodine receptor : calcium pump D) calcium pump : ryanodine receptor E) calcium-induced calcium release channel : dihydropyridine receptor Which of the following is the voltage sensor that initiates an increase in cytoplasmic calcium in response to an action potential? A) dihydropyridine receptor B) ryanodine receptor C) calcium pump D) calcium-induced calcium release channel E) sodium channel Which of the following best describes the function of transverse (t) tubules and the sarcoplasmic reticulum in skeletal muscle contraction? A) Action potentials in T tubules trigger the release of acetylcholine, which binds to receptors on the sarcoplasmic reticulum and triggers calcium release. B) Action potentials in T tubules trigger the release of norepinephrine, which binds to receptors on the sarcoplasmic reticulum and triggers calcium release. C) Action potentials in T tubules are detected by DHP receptors, which are coupled to ryanodine receptors in the sarcoplasmic reticulum and open channels for calcium. D) Action potentials in T tubules are detected by ryanodine receptors, which are coupled to DHP receptors in the sarcoplasmic reticulum and open channels for calcium. E) Action potentials in T tubules cause a depolarization of the sarcoplasmic reticulum membrane, thereby opening calcium channels to trigger calcium release. The major inhibitory neurotransmitter rostral to the brainstem is? A. GABA B. Glycine C. Glutamate D. Acetylcholine The major inhibitory neurotransmitter of brainstem and spinal cord is? A. GABA B. Glycine C. Glutamate D. Acetylcholine Which of the following is NOT true about excitatory postsynaptic potentials (EPSPs)? A. Hyperpolarize the membrane of the postsynaptic cell B. Can be strengthened C. Bring the membrane of the postsynaptic cell closer to threshold for action potentials D. Are produced by excitatory cells Which of the following is NOT true about Inhibitory postsynaptic potentials (IPSPs)? A. Hyperpolarize the membrane of the postsynaptic cell B. Make the postsynaptic cell less likely to fire an action potential C. Bring the membrane of the postsynaptic cell closer to threshold for action potentials D. Are produced by inhibitory cells Which of the following is NOT true about chemical synapses? A. Neurotransmitter is stored in vesicles B. Calcium is necessary for neurotransmitter exocytosis C. LTD produces strengthening of the synapse D. Can be excitatory or inhibitory Which of the following is NOT true about electrical synapses? A. Formed by gap junctions B. Have connexon channels C. Are a fast form of communication D. Use neurotransmitters that bind to receptors Which of the following statements referring to Excitatory Postsynaptic Potentials (EPSPs) is INCORRECT? a. EPSPs are transmitted from dendrites to the action potential trigger zone mainly passively. b. EPSPs are typically evoked by the amino acid glycine. c. EPSPs are produced by opening of channels in the postsynaptic membrane that are permeable to more than one cation (Na", K" and sometimes Ca2*). d. EPSPs are usually ineffective in depolarising the trigger zone to threshold, when produced by activation of only one or of a small number of excitatory synapses. 21) Which autonomic receptor mediates secretion of epinephrine by the adrenal medulla? a. Adrenergic a receptors b. Adrenergic 01 receptors c. Adrenergic 02 receptors d. Cholinergic muscarinic receptors e. Cholinergic nicotinic receptors 22) Cutting which structure on the right side causes blindness in the temporal field of the left eye and the nasal field of the right eye? a. Optic nerve b. Optic chiasm c. Optic tract d. Geniculocalcarine tract 23) Which of the following parts of the body has cortical motoneurons with the largest representation on the primary motor cortex (area 4)? a. Shoulder b. Ankle c. Fingers d. Elbow e. Knee 24) Which adrenergic receptor produces its stimulatory effects by the formation of inositol 1,4,5- triphosphate (IP3) and an increase in intracellular [Ca2+]? a. A1 Receptors b. A2 Receptors c. B1 Receptors d. B2 Receptors 25) Administration of which of the following drugs is contraindicated in a 10-year-old child with a history of asthma? a. Albuterol b. Epinephrine c. Isoproterenol d. Norepinephrine e. Propranolol 26) Which reflex is responsible for monosynaptic excitation of ipsilateral homonymous muscle? a. Stretch reflex (myotatic) b. Golgi tendon reflex (inverse myotatic) c. Flexor withdrawal reflex d. Subliminal occlusion reflex 27) Which type of cell in the visual cortex responds best to a moving bar of light? a. Simple b. Complex c. Hypercomplex d. Bipolar e. Ganglion 28) Which of the following responses is mediated by parasympathetic muscarinic receptors a. Dilation of bronchiolar smooth muscle b. Erection c. Ejaculation d. Constriction of gastrointestinal (GI) sphincters e. Increased cardiac contractility 29) Which of the following is a property of C fibers? a. Have the slowest conduction velocity of any nerve fiber type b. Have the largest diameter of any nerve fiber type c. Are afferent nerves from muscle spindles d. Are afferent nerves from Golgi tendon organs e. Are preganglionic autonomic fibers Action potential Short lasting excitation of cell membrane potential rises rapidly then falls Na+/K+ Pump Maintains membrane polarity (Na= out & K=IN, against concentration gradient) Which agent should be avoided if the patient is taking an MAO inhibitor? (Select 2) A. Meperidine B. Labetalol C. Epinephrine D. Phenylephrine Which of the following is a false statement about C fibers? A. They carry diffuse and persistent burning, aching and throbbing pain B. They carry "slow" pain or "second" pain C. They are myelinated D. They have cell bodies located in dorsal root ganglion What nerves pass through the gray rami communicans? A. Parasympathetic preganglionic neurons B. Parasympathetic postganglionic neurons C. Sympathetic preganglionic neurons D. Sympathetic postganglionic neurons What nerves originate in the intermediolateral horn of the spinal cord? A. A-alpha motor neurons B. Sympathetic preganglionic neurons C. A-beta neurons D. C fibers Which of the following structures is not innervated by the stellate ganglia? A. Bronchioles B. Pupils C. Eyelids D. Nasal vasculature Insulin receptors contain an active tyrosine kinase domain. What is the function of a kinase? A. Kinases exchange GTP for GDP B. Kinases activate calcium channels on the endoplasmic reticulum C. Kinases catalyze the addition of a phosphate group to a substrate D. Kinases degrade cAMP and cGMP to inactive products Proprioception is carried by A. A-alpha fibers B. A-gamma fibers C. A-delta fibers D. dC fibers In the patient who is chronically beta-blocked, the beta receptors A. Increase in number B. Decrease in number C. Become hypersensitive to beta- adrenergic agonists D. Become insensitive to beta-adrenergic agonists The effects of Ephedrine are due mostly to its A. Stimulation of the nerve terminal to release norepinephrine B. Direct stimulation of alpha 1 & 2 receptors C. Direct stimulation of beta 1 & 2 receptors D. Direct stimulation of alpha and beta receptors Release of neurotransmitter requires the entry of what substance into the nerve terminal? A. Sodium B. Potassium C. Magnesium D. Calcium Postsynaptic nicotinic receptors are found at each of the following site EXCEPT: A. Adrenal medulla B. SA node C. Autonomic ganglia D. Skeletal muscle motor-end plate The presynaptic action of succinylcholine A. Enhances its postsynaptic action B. Antagonizes its postsynaptic action C. Does not alter is postsynaptic action The release of acetylcholine from the neuromuscular junction will be increased in which of the following conditions? A. Hyponatremia B. Hypocalcemia C. Hypomagnesemia D. Hypokalemia Sodium, calcium and potassium ions diffuse in which directions when the channels of the motor-end plate of skeletal muscle are stimulated to open? Sodium/ Calcium/ Potassium A. Inward/ Inward/ Outward B. Outward/ Outward/ Inward C. Inward/ Inward/ Inward D. Outward/ Outward/ Outward How many molecules of acetylcholine are required to open a channel of the motor-end plate? A. One B. Two C. Three D. Four Stimulation of presynaptic and postsynaptic nicotinic receptors at the neuromuscular junction leads to which of the following set of responses? Release of Acetylcholine/ Motor End Plate Potential A. Decreased/ Increased (hyper polarized) B. Decreased/ Decreased (depolarized) C. Increased/ Increased (hyper polarized) D. Increased/ Decreased (depolarized) Where is vasopressin (ADH) synthesized and what stimulates its release? (Select 2) A. Neurohypophysis B. Hypothalamus C. Increased osmolality D. Decreased osmolality The resting potential of a myelinated nerve fiber is primarily dependent on the concentration gradient of which of the following ions? A. Ca++ B. Cl- C. HСO3- D. K+ E. Na+ The neurotransmitter g-amino butyric acid (GABA) binds to receptors that are ligand-gated Cl- ion channels. What affect will this neurotransmitter have on the post-synaptic cell? A. Cl- ions will rush into the cell leading to hyperpolarization and a reduced likelihood of an action potential. B. Cl- ions will rush into the cell leading to depolarization and an increase in the chance for an action potential. C. Cl- ions bind to GABA and inhibit it from interacting with the receptor, stimulating an action potential. D. There will be no significant effect on the post-synaptic cell; only the pre-synaptic cell is affected by neurotransmitters. Which of the following is the most likely immediate affect of G-protein activation? A. Receptors are stimulated to bind to their ligands. B. Enzymes are activated that catalyze second messenger formation. C. GTP is depleted from the cell. D. G-proteins bind to DNA and activate gene expression. Apoptosis is mediated by signal transduction pathways that lead to the programmed death of the cell. How is cell death achieved during apoptosis? A. Aqueous channels form in the cell membranes leading to inward movement of water and lysis of the cell. B. Gene expression is activated that leads to the synthesis of inhibitors of respiratory enzymes. C. The Na+/K+ ATPase is inactivated, leading to the loss of membrane potential which the cell needs to survive. D. Caspases are activated that lead to hydrolysis of many cellular macromolecules. Which of the following statements is NOT true of tyrosine kinase-linked receptors? A. Monomeric receptors are often induced to dimerize upon ligand binding. B. The activated receptors attract and activate G proteins to continue the signal pathway. C. The cytoplasmic side of the receptor contains a kinase enzyme domain that is activated upon ligand binding. D. Activated receptors autophosphorylate themselves to attract SH2 domain proteins. Axoplasmic flow A. requires actin and Ca2+. B. can be retrograde. C. is relatively fast. D. results from rhythmic waves of contraction. Ion channels that open in response to depolarization are called A. ion-gated channels. B. voltage-gated channels. C. stimulation-gated channels. D. potential-gated channels. Blocking ____________ channels would prevent neuronal depolarization. A. K+ B. Cl- C. Na+ D. Mg2+ During an action potential A. Na+ efflux causes depolarization. B. K+ influx causes repolarization. C. Na+ influx causes depolarization. D. K+ influx causes after-hyperpolarization The mechanism that allows many Na+ ions to move into the axon is A. negative feedback. B. positive feedback. C. equilibrium feedback. D. None of the choices are correct. An axon will depolarize only if the membrane potential reaches between -70mV and -55mV. This follows the A. All-or-none law. B. recruitment law. C. graduated law. D. threshold law. The minimum depolarization needed to open Na+ gates is called the A. repolarization. B. threshold. C. refractory period. D. All-or-none law. The period of time when Na+ channels are recovering from their inactive state and K+ channels are still open is the A. repolarization. B. absolute refractory period. C. relative refractory period. D. Both repolarization and relative refractory period are correct. Action potentials would be conducted most rapidly by A. a 10 mm diameter myelinated axon. B. a 10 mm diameter unmyelinated axon. C. a 40 mm diameter myelinated axon. D. a 40 mm diameter unmyelinated axon Conduction of an action potential in a myelinated axon is called A. point to point conduction. B. saltatory conduction. C. refractory conduction. D. cable conduction. ______ synapses occur between axons of postsynaptic cells and axons of presynaptic cells. A. Axodendritic B. Axosomatic C. Myoneural D. Axoaxonic In a myelinated axon, Na+ channels are A. along the whole length of the axon. B. every 5 mm. C. concentrated at the nodes of Ranvier. D. less numerous at the nodes of Ranvier. Chemicals that stimulate action potentials in postsynaptic cells are called A. hormones. B. enzymes. C. neurotransmitters. D. neurotrophins Chemical synapses A. have a delayed impulse transmission. B. utilize gap junctions. C. occur when two nerve cells are in direct contact with each other. D. do not require the release of neurotransmitters. What type of proteins are present in gap junctions that form water-filled channels between neurons? A. connexons B. myelin C. terminal boutons D. cell adhesion molecules (CAMs) What type of proteins are present at chemical synapses to ensure the close proximity of the presynaptic and postsynaptic membranes? A. connexins B. myelin C. terminal boutons D. cell adhesion molecules (CAMs) Synaptic vesicles are docked to the plasma membrane of the axon terminal by a protein complex called A. boutons. B. connexons. C. synaptotagmins. D. SNARE. Neurotransmitter release would be inhibited by A. stimulating repolarization of the axon terminal. B. blocking Ca2+ influx in the axon terminal. C. blocking repolarization of the axon terminal. D. stimulating protein kinase activity. Hyperpolarization in the postsynaptic cell is caused by A. excitatory postsynaptic potentials. B. inhibitory postsynaptic potentials. C. movement of K+ out of the cell. D. Both inhibitory postsynaptic potentials and movement of K+ out of the cell are correct. Neurotransmitters A. are released by endocytosis. B. all bind to the same receptor. C. usually regulate ion channels. D. are actively transported across the synaptic cleft. The binding of a NT to its receptor protein causes ion channels to open in the post-synaptic membrane. What type of gates are these? A. chemically-regulated gates B. voltage-regulated gates C. ligand-regulated gates D. Both chemically-regulated gates and ligand-regulated gates are correct. Acetylcholine A. is always an excitatory neurotransmitter. B. can bind to adrenergic receptors. C. is an inhibitory neurotransmitter released by motor neurons. D. can bind to nicotinic receptors. Acetylcholine usually induces an excitatory postsynaptic potential when binding to ________ receptors and an inhibitory postsynaptic potential when binding to ____________ receptors. A. NMDA, nicotinic B. nicotinic, muscarinic C. muscarinic, NMDA D. muscarinic, nicotinic Acetylcholine can induce hyperpolarization by A. binding to nicotinic receptors. B. binding to muscarinic receptors. C. binding to a-adrenergic receptors. D. binding to b-adrenergic receptors. What portion of the neuron is NOT involved in integration? A. cell body B. axon C. dendrites D. axon hillock Cholinergic fibers use ____ as the neurotransmitter. A. norepinephrine B. acetylcholine C. dopamine D. serotonin Serotonin is synthesized from the amino acid A. alanine. B. glycine. C. tryptophan. D. serine. Monoamine NTs are degraded by A. acetylcholinesterase. B. monoamine oxidase. C. catechol-O-methyltransferase. D. adenylate cyclase. Catecholamines activate postsynaptic cells by A. inhibition of adenylate cyclase. B. increased Ca2+ influx into the target cell. C. inhibition of calmodulin. D. increased production of cyclic AMP. The mesolimbic dopamine neurons arise in the midbrain and terminate in the A. nucleus accumbens. B. corpus striatum. C. basal nuclei. D. corpus callosum. Which of the following is NOT a type of glutamate receptor? A. NMDA receptor B. muscarinic receptor C. kainate receptor D. All of the choices are correct. Excitatory postsynaptic potentials are produced by A. glycine. B. glutamic acid. C. gamma-aminobutyric acid. D. benzodiazepines. Benzodiazepines act by increasing ________ activity. A. GABA B. glutamate C. Ach D. enkephalin The most common neurotransmitter in the brain is A. glycine. B. acetylcholine. C. serotonin. D. GABA. Relaxation of cerebral blood vessels would be stimulated by excessive ________ activity. A. nitric oxide B. Ach C. norepinephrine D. glutamate Nitric oxide A. is a chemical messenger activating adenylate cyclase. B. stimulates the dilation of blood vessels. C. is produced from L-asparagine. D. All of the choices are correct. Which gas(es) can function as a neurotransmitter? A. carbon dioxide B. nitric oxide C. carbon monoxide D. both nitric oxide and carbon monoxide. Spatial summation A. occurs when a single neuron releases neurotransmitter rapidly. B. occurs because of the convergence of many neurons on a single postsynaptic cell. C. only involves excitatory postsynaptic potentials. D. only involves inhibitory postsynaptic potentials. Excitotoxicity is caused by A. insufficient synaptic release of glutamate. B. excessive synaptic release of glutamate. C. GABA inhibition. D. insufficient synaptic release of Ach. Both long-term potentiation and long-term depression requires release of ___ from the postsynaptic neuron membrane. A. Cl- B. K+ C. Ca2+ D. Mg2+ Postsynaptic inhibition is caused by A. Acetylcholine B. GABA C. glycine D. Both GABA and glycine Direct-acting neurotransmitters ________. A) open ion channels to provoke rapid responses B) require cyclic AMP C) mediate very slow responses D) act through second messengers Which of the following is correct relative to Ohm's law? A) The more intense the stimulus, the more voltage changes. B) R = V + I C) I = R / V D) Current is directly proportional to the voltage. Ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid are called ________. A) Schwann cells B) ependymal cells C) astrocytes D) oligodendrocytes The sheath of Schwann is also called the ________. A) myelin sheath B) neurilemma C) white matter D) axolemma Bipolar neurons are commonly ________. A) found in the retina of the eye B) called neuroglial cells C) motor neurons D) found in ganglia An excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle is ________. A) gamma aminobutyric acid B) norepinephrine C) acetylcholine D) cholinesterase A neural circuit in which a single impulse is transmitted over and over is a ________. A) reverberating circuit B) repetitive circuit C) converging circuit D) diverging circuit The period after an

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