CH 11 Nervous System Past Paper PDF

CH 11 Nervous System WHOLE Chapter BigQuiz/Test​ ​ FULL REVIEW SHEET (2pages) DETAILS ON QUIZ LAYOUT 50 SCANTRON – MCQ, MATCHING, T/F TYPE QS PLUS !!! A MANDATORY FREE RESPONSE – EXPECT TO DRAW A LABELED AP GRAPH!!- so practice !! ONE OR TWO SHORT ANSWER (fe...

CH 11 Nervous System WHOLE Chapter BigQuiz/Test​ ​ FULL REVIEW SHEET (2pages) DETAILS ON QUIZ LAYOUT 50 SCANTRON – MCQ, MATCHING, T/F TYPE QS PLUS !!! A MANDATORY FREE RESPONSE – EXPECT TO DRAW A LABELED AP GRAPH!!- so practice !! ONE OR TWO SHORT ANSWER (few sentence Concept Qs ) TIME 60 MINUTES -this means that the basic fact Qs need to be ready for instant recall Functions and Divisions of the Nervous System ​ Overall organization of the NS List the basic functions of the nervous system. The Nervous System: -​ master controlling and communicating system of body -​ cells communicate via electrical and chemical signals -​ rapid and specific (very immediate response) CNS: -​ consists of brain and spinal cord PNS: -​ consists of cranial nerves and spinal nerves  ​ Explain the basic structural and functional divisions of the nervous system. Histology of Nervous Tissue ​ 2 major cell groups – Know the SIX Neuroglia types, functions, locations Highly cellular: little extracellular space -​ tightly packed; very little to no connective tissue Two major cell types: Neuroglia- small cells that surround and wrap delicate neurons = support cells Neuroglia in the CNS: -​ Astrocytes -​ most abundant -​ 90% of all brain tissue; covers brain -​ highly branched -​ clings onto neurons, synaptic endings, and capillaries -​ supports and braces neurons -​ plays role in gas exchanges in the brain (between capillaries and neurons) -​ guides migration of young neurons in embryo -​ controls chemical environment around neurons -​ responds to nerve impulse and neurotransmitters -​ influences neuronal functioning -​ participates in information processing in brain  -​ Microglial cells -​ small ovoid cells -​ thorny processes that touch and monitor neurons -​ constantly moving to monitor and clean up -​ migrates toward injured neurons -​ can transform to phagocytize microorganisms and neuronal debris -​ Ependymal Cells -​ range in shape from squamous to columnar -​ modified epithelial cells -​ may be ciliated -​ cilia to circulate CSF -​ lines central cavities of the brain and spinal column -​ forms permeable barrier between CSF in cavities and tissue fluid bathing CNS cells -​ Forms part of BBB -​ Oligodendrocytes -​ branched cells -​ have processes that wrap CNS nerve fibers -​ forms insulating myelin sheaths- thicker nerve fibers -​ forms lipids Neuroglia in the PNS: -​ Satellite cells -​ surround neuron cell bodies in PNS -​ function similar to astrocytes of CNS -​ Schwann cells (neurolemmocytes) -​ surround all peripheral nerve fibers and form myelin sheaths in thicker nerve fibers -​ similar to oligodendrocytes -​ Vital to regeneration of damaged peripheral nerve fibers  ​ Neurons - Neuron anatomy- Define neuron, describe its important structural components, and relate each to a functional role.3 functional Zones Neurons (nerve cells)- excitable cells that transmit electrical signals- highly specialized -​ structural and functional units of nervous system -​ large cells that conduct impulses -​ long life span (100 years +) -​ high metabolic rate; requires continuous supply of oxygen and glucose -​ all have cell body and one or more processes  ​ Differentiate between (1) a nerve and a tract, and (2) a nucleus and a ganglion. ​ Explain the importance of the myelin sheath and describe how it is formed in the central and peripheral nervous systems. compare in CNS to PNS how why where Myelin Sheath: -​ protects and electrically insulates axon -​ increases speed of nerve impulse transmission -​ myelinated fibers conducts impulses faster -​ nonmyelinated fibers conducts impulses slower Myelin Sheath in the CNS: -​ oligodendrocytes form myelin sheath in the CNS -​ can coil around as many as 60 axons at the same time -​ in the CNS, myelin sheath lack an outer collar of perinuclear cytoplasm because cell extension do the coiling -​ squeezed out cytoplasm is forced back toward the centrally located nucleus instead of peripherally Myelin Sheath in the PNS: -​ schwann cells form myelin sheath in the PNS -​ it wraps itself around the axon in jelly roll fashion -​ the wrapping is loose initially, but the schwann cell cytoplasm is then squeezed tightly -​ it’s thickness depends on the number of spirals -​ the nucleus and most of the cytoplasm from the schwann cell end up as a bulge just external of the myelin sheath called the outer collar of perinuclear cytoplasm (aka neurilemma) ​ Classification of neurons by 3 main shapes , and function examples and locations and functions Membrane Potentials ​ Define resting membrane potential and describe its electrochemical basis. RMP details of membrane and how it is set and maintained Resting Membrane Potential: -​ the voltage that exists across the plasma membrane during the resting state of an excitable cell; typically ranges from -50 to -90 mV depending on cell type − − -​ cell is not actively sending signals -​ ions must flow through their specific channel -​ can be open, leaky, or gated channels -​ the cell is typically negative on the inside due to negative proteins and positive on the outside -​ RMP is generated by -​ differences in ions in ICF and ECF -​ difference in permeability of the plasma membrane -​ K+ is more permeable than Na+ -​ Na/K pump: 3 Na+ out , 2 K+ in ​ Graded potentials what are they where are they why are they-relate to EPSP,IPSP Graded Potential: -​ incoming signals operating over short distances (trigger) -​ short lived and diminishes its strength with distances -​ can be either depolarization or hyperpolarization -​ locations could be in sensory receptors, dendritic spines or postsynaptic knob -​ sums together to determine if an AP can occur or not -​ causes voltage changes -​ its magnitude depends on its stimulus strength -​ Graded potentials are the underlying mechanism for both excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs), meaning that EPSPs and IPSPs are essentially types of graded potentials that occur at the postsynaptic membrane of a neuron, either depolarizing the membrane (bringing it closer to firing an action potential - EPSP) or hyperpolarizing it (making it less likely to fire an action potential - IPSP) depending on the neurotransmitter involved; both are graded because their amplitude varies depending on the strength of the stimulus ​ Compare and contrast graded potentials and action potentials.  ​ KNOW how to DRAW the 4 Steps of an Action potential Graphs and know each step (HW review) ​ Details of the AP: threshold, AP propagation, Explain how action potentials are generated and propagated along neurons. AP: -​ a brief change in membrane potential with a change in voltage of 100 mV (-70 mV to +30 mV) -​ generated by a stimulus (neurotransmitter) and influx of Na+ -​ involves opening of specific voltage gated channels -​ each Na+ channel has two voltage-sensitive gates -​ activation gate: -​ closed at rest; open with depolarization allowing Na+ to enter cell -​ inactivation gate: -​ open at rest; block channel once it is open to prevent more Na+ from entering cell -​ each K+ channel has one voltage-sensitive gate -​ closed at rest -​ opens slowly with depolarization -​ threshold needs to reach at -55 - -50 mV to create AP -​ Na+ permeability increases -​ Na+ influx exceeds K+ efflux -​ "Propagation of action potential" refers to the process where an electrical signal, called an action potential, travels along the length of a neuron (nerve cell), essentially "spreading" the signal like a wave from one point of the cell membrane to the next, allowing for the transmission of information within the nervous system; it's essentially how a nerve impulse moves along a neuron ​ Define absolute and relative refractory periods. ​ Define saltatory conduction and contrast it to continuous conduction. ​ Stimulus intensity is based on ? -​ strong stimuli generates nerve impulses more often in a given time interval than do weak stimuli -​ stimuli intensity is coded for by the number of impulse per second, rather than increases in the strength of the individuals AP  ​ Conduction velocity - factors affecting this Axon diameter: -​ the larger the axons diameter, the faster the impulse is conducted -​ offers less resistance to the flow of impulses within the current Degree of myelination: -​ the more myelination, the faster the impulse is conducted ​ Fiber types A,B,C The Synapse ​ Define synapse. chemical synapses by structure and -​ Synapse: a junction between two presynaptic and postsynaptic neurons -​ Chemical synapse: chemical messenger is transmitted across the junction separating the two neurons -​ found in most synapses between neurons and all synapses between neurons and other cells -​ cells are not in direct contact -​ AP may or may not be propagated to postsynaptic cell depending on the amount of neurotransmitter released (which determines the strength of the AP), sensitivity of postsynaptic cell, types of synapse, and type of neurotransmitter ​ Synaptic transmission 6 steps by the way they transmit information. ​ Distinguish between excitatory and inhibitory postsynaptic potentials. EPSP,IPSP -​ Excitatory Postsynaptic Potential (EPSP): graded depolarization of postsynaptic membrane -​ “gathers” the charge at the postsynaptic cell body and “sends it” to the axon hillock to generate an AP -​ graded in magnitude -​ no threshold -​ summate -​ has no refractory period -​ one single EPSP cannot induce an AP, needs to add together (summate) -​ Inhibitory Postsynaptic Potential (IPSP): graded hyperpolarization of postsynaptic membrane -​ makes membrane more permeable to K+ and CI- -​ gradual influx of CI- occurs due to binding of neurotransmitter with an inhibitory effect -​ inner membrane becomes more negative (as low as -90mV) -​ less likely for an AP -​ small in magnitude -​ makes membrane less excitable -​ suppresses continuation of impulse along axon -​ important in moderation/control of response -​ summate Behavior occurs when neurons are released from inhibition = when EPSP overrides IPSP Summation: To trigger an AP (The combination of multiple impulses can create a response, such as an action potential.) -​ Spatial summation: The combined effect of multiple simultaneous inputs from different synapses. -​ Temporal summation: The combined effect of repeated inputs from the same synapse. Inhibition: a neuron that receives many IPSP -​ is inhibited from producing an action potential -​ because the stimulation needed to reach threshold is increased  ​ Describe how synaptic events are integrated and modified. Summation by the postsynaptic neuron: -​ one single EPSP cannot induce an AP, needs to add together (summate) -​ mst neurons receive both excitatory and inhibitory inputs from thousands of other neurons ​ ​​ - only if EPSP predominates and brings to threshold will an AP be generated -​ Spatial and Temporal summation Synaptic potentiation: -​ repeated use of synapse increases ability of presynaptic cell to excite postsynaptic neuron -​ Ca2+ concentration increases presynaptic terminal, causing releases of more neurotransmitters -​ leads to more EPSP in postsynaptic neuron -​ potentiation can cause Ca2+ voltage gates to open on postsynaptic neuron -​ Ca2+ activates kinase enzymes, leading to more effective response to subsequent stimuli -​ Long term potentiation: learning and memory Presynaptic Inhibition: -​ occurs when the release of excitatory neurotransmitters by one neuron is inhibited by the activity of another neuron via an axoaxonal synapse -​ less neurotransmitter is released and bound, forming smaller EPSP -​ decreases the excitatory stimulation of the postsynaptic neuron -​ temporarily turns off specific synapses ​ ​ How synaptic delay and fatigue affect speed of transmission Synaptic Delay: -​ time needed for neurotransmitter to be released, diffuse across synapse, and bind to receptors -​ Transmission of AP down axon can be very quick, but synapse slows transmission to postsynaptic neuron down significantly (isn’t very noticeable because it still is very fast) Synaptic Fatigue: -​ occurs when a neurotransmitter cannot recycle fast enough to meet demands of intense stimuli -​ synapse inactive until ACh is replenished -​ “excessive firing of a nerve” ​ EPSP, IPSP summation of these to generate an AP (Or not!!) and why -​ whichever has the most within the neuron! (more EPSP = AP , more IPSP = no AP) -​ if there's equal amount, they nearly cancel each other out Neurotransmitters and Their Receptors Define neurotransmitter and name several classes of neurotransmitters -​ 80 plus chemical substances that provide communication between cells -​ some of these are actually NT and others are neuromodulators -​ the most commons neurotransmitter in PNS is acetylcholine which is an excitatory NT -​ same neurotransmitter is always released at a specific synapse -​ can either stimulate or inhibit a response NT Classes: -​ Excitatory neurotransmitters -​ cause depolarization of postsynaptic membranes -​ promote AP -​ Inhibitory neurotransmitters -​ cause hyperpolarization of postsynaptic membrane -​ suppress AP -​ Direct action of neurotransmitter -​ neurotransmitter binds to membrane receptor and channels open -​ Indirect action of neurotransmitter -​ neurotransmitter causes the production of a second messenger which will ultimately lead to opening of channels KNOW THE MAIN EXCITATORY NTs and their effect at the synapse Ach and Glutamate and The 2 MAIN Inhibitory NTs and their effect at the synapse GABA and ? Excitatory: Acetylcholine: -​ ACh is released by all neurons that stimulate skeletal muscles and by many neurons of the autonomic nervous system -​ ACh releasing neurons are also found in the CNS -​ diffuses across the synaptic cleft and binds to special receptors on the postsynaptic or the postjunctional membrane -​ triggers the firing of motor neurons and affecting voluntary movements -​ stimulates postsynaptic cell, leading to signal transmission Glutamate -​ glutamate acts as an excitatory neurotransmitter, meaning when released from the presynaptic neuron, it binds to receptors on the postsynaptic neuron, causing it to become more likely to fire an action potential by depolarizing the membrane, essentially strengthening the signal between the two neurons Inhibitory: GABA: -​ decreases the likelihood of a postsynaptic neuron firing an action potential be hyperpolarizing the cell membrane, effectively calming neural activity when it binds to its receptors on the postsynaptic neuron; this occurs primarily by allowing chloride ions to flow into the cell, making the inside more negative. -​ has a “calming” effect Glycine: -​ meaning it suppresses neuronal firing by binding to glycine receptors on the postsynaptic membrane, which then opens chloride channels, causing the neuron to hyperpolarize and become less likely to fire an action potential; -​ this effect is particularly prominent in the spinal cord and brainstem. Know** Excitatory Cholinergic effect =direct AP → know targets -​ nerve signal opens voltage gated calcium channels in synaptic knob -​ triggers release of ACh which crosses synapse -​ ACh receptors trigger opening of Na+ channels producing local potential (postsynaptic potential) -​ when reaches -55mV, triggers AP in postsynaptic neuron Excitatory Adrenergic effect = 2nd Messenger (cAMP) indirect → know targets -​ is NE (norepinephrine) -​ receptor is an integral membrane protein associated with a G protein, which activates adenylate cyclase, which converts ATP to cAMP -​ cAMP can… -​ bind to ion gate inside of membrane (depolarization) -​ activate cytoplasmic enzymes -​ induce genetic transcription and production of new enzymes -​ advantage in enzymatic amplification Inhibitory GABA-ergic effect → Hyperpolarize -​ nerve signal triggers release of GABA which crosses synapse -​ GABA receptors trigger opening of CI- channels producing hyperpolarization -​ postsynaptic neuron now less likely to reach threshold Basic Concepts of Neural Integration Know the common patterns of neuronal organization and processing. As shown in class