Physiology 1 Final Exam

Physiology Exam Review

Membrane Depolarization

• Receptor potential: a type of graded potential that develops in sensory receptors in response to adequate stimuli
• Local response: a type of graded potential that develops in response to local stimulation of a sensory receptor

Action Potential Generation

• An action potential is initiated in the soma-axon hillock
• The action potential is propagated along the axon to the terminal
• The action potential is an all-or-nothing response, meaning it always runs its course to completion

Anterior Pituitary Hormones

• Adrenocorticotropic hormone (ACTH) regulates nonendocrine target cells
• Thyroid-stimulating hormone (TSH) regulates thyroid function
• Prolactin regulates lactation
• Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) regulate reproductive function

Muscle Physiology

• T tubules contain sarcoplasmic reticulum, which stores calcium ions
• Neuromuscular transmission occurs at the motor endplate
• The contractile response of skeletal muscle is triggered by a rise in intracellular calcium ions

Synaptic Transmission

• Neurotransmitter is stored and released from axon terminals
• The release of neurotransmitter is dependent on the influx of calcium ions into the terminal
• The action of a neurotransmitter is determined by the type of receptor it binds to

Resting Membrane Potential

• The resting membrane potential is dependent on the permeability of the cell membrane to potassium ions
• The resting membrane potential is typically around -70mV

Smooth Muscle Contraction

• Smooth muscle contraction is triggered by a rise in intracellular calcium ions
• Smooth muscle contraction is slower and more sustained than skeletal muscle contraction

Fertilization

• Fertilization normally occurs in the ampulla of the fallopian tube

Hormone Regulation

• Growth hormone preferentially metabolizes fats
• Parathyroid hormone regulates calcium and phosphate levels in the blood

Skeletal Muscle

• Skeletal muscle is made up of individual fibers containing sarcomeres
• The contractile response of skeletal muscle is triggered by a rise in intracellular calcium ions

Neuronal Transmission

• The sodium pump is responsible for maintaining the transmembrane concentration difference of sodium and potassium ions
• Neurotransmitter release is dependent on the influx of calcium ions into the terminal

Adrenal Medulla

• The adrenal medulla receives synaptic input from preganglionic sympathetic neurons### Synthesis of Acetylcholinesterase
• Synthesis of acetylcholinesterase is not directly related to the synaptic terminal
• Hyperpolarization of the synaptic terminal is not related to synthesis of acetylcholinesterase
• Fusion of synaptic vesicles with the postsynaptic membrane is not related to synthesis of acetylcholinesterase
• Opening of ligand-gated calcium ion channels and influx of calcium into the synaptic terminal are not related to synthesis of acetylcholinesterase

Endocrine Glands

• Adrenal medulla is under direct nervous control
• Thyroid, parathyroid, and adrenal cortex are not under direct nervous control

Nerve Signaling

• Nerve cells propagate signals along their axons by means of action potentials
• Electrotonic potentials, local response, postsynaptic potentials, and receptor potentials are not the primary means of signal propagation

Myxedema

• Somnolence is a likely finding in a patient with myxedema
• Palpitations, increased respiratory rate, increased cardiac output, and weight loss are not typical findings in myxedema

Milk Production

• Prolactin stimulates milk production by the breast
• It takes place in myoepithelial cells, begins during the last month of pregnancy, and is responsive to changes in demand for milk from the breast

Anticholinesteratic Drug

• Anticholinesteratic drug inhibits acetylcholinesterase
• It does not inhibit acetylcholine synthesis, block acetylcholine axoplasmic transport, break down released acetylcholine, or block the action of acetylcholine on cholinergic receptors

Action Potential

• Movement of Na+ into the cell is primarily responsible for the depolarization during an action potential
• Movement of Na+ out of the cell, movement of K+ into the cell, movement of K+ out of the cell, and inhibition of the Na+, K+-ATPase are not primarily responsible for the depolarization during an action potential

Refractoriness

• A new action potential cannot be elicited in an excitable fiber as long as the membrane is still depolarized from the preceding action potential, known as refractoriness
• Safety factor, all or none principle, accommodation, and adaptation are not referring to this concept

Excitation-Contraction Coupling

• Excitation-contraction coupling in skeletal muscle involves increase in the permeability of the muscle fiber to Na+, binding of Ca++ to calmodulin, conformational change in the dihydropyridine receptor, depolarization of the transverse tubule (T tubule) membrane, and ATP hydrolysis
• Increase in the permeability of the muscle fiber to Na+, binding of Ca++ to calmodulin, and ATP hydrolysis are not involved in excitation-contraction coupling in smooth muscle

Hormones

• Growth hormone exerts the least effect on growth
• Testosterone, T4, insulin, and vasopressin have a more significant effect on growth

Insulin Secretion

• Amino acids and glucose are likely to produce the greatest increase in insulin secretion
• Amino acids, amino acids and somatostatin, and glucose and somatostatin are less likely to increase insulin secretion

Autonomic Nervous System

• Sympathetic division of autonomic nervous system prepares the body for activity ("flight or fight")
• Parasympathetic division promotes restorative function of body ("rest and digest"), plays an important part in the regulation of the motility and secretory activity of the digestive system, and plays an important part in the trophic function of skeletal muscles

Action Potential in Skeletal Muscle

• Action potential in skeletal muscle causes the immediate uptake of Ca++ into the lateral sacs of the sarcoplasmic reticulum and spreads inward to all parts of the muscle via the T tubules
• It has a prolonged plateau phase, is longer than the action potential of cardiac muscle, and is essential for contraction

Presynaptic Inhibition

• Presynaptic inhibition occurs at the synaptic terminals before the signal ever reaches the synapse
• Postsynaptic inhibition, recurrent inhibition, and others are different types of inhibition

Muscle Contraction

• Increasing the frequency of stimulation causes the force of skeletal muscle contraction to be increased due to an increase in the number of cross-bridges binding to actin
• Increase in intracellular Ca++ concentration, duration of the active state, and activity of myosin ATPase are not directly responsible for the increased force of contraction

Cellular Signaling

• Cells respond to chemical signals by initiating an appropriate physiological response, known as transduction
• Conduction, transmission, inhibition, and transformation are different processes

Muscle Regulation

• Troponin-tropomyosin complex is activated by calcium ions
• Sodium, potassium, and chloride ions do not activate the troponin-tropomyosin complex

Hormone Binding

• Cortisol is largely bound to plasma proteins
• Thyroxine, antidiuretic hormone, estradiol, and progesterone are not largely bound to plasma proteins

Myelination

• Myelination increases the velocity of nerve impulses along the axon
• Increase in the nonselective diffusion of ions across the axon membrane, decrease in the velocity of nerve impulses along the axon, increase in the energy required to maintain ion gradients across the membrane, and generation of action potentials only at the nodes of Ranvier are not consequences of myelination

Cellular Communication

• Paracrine regulation refers to the secretion of chemicals into the extracellular fluid that act on cells in the same tissue
• Neural, endocrine, neuroendocrine, and autocrine regulation are different types of regulation

Cellular Contact

• Electric synapse operates by transmitting the electric current generated by the action potential to the neighbor cell via gap-junctions
• Chemical synapse, tight-junction, neuromuscular junction, and syncytium are different types of cellular contacts

Smooth Muscle

• Visceral smooth muscle differs from skeletal muscle in that it can contract in response to stretch
• Visceral smooth muscle contains actin filaments, can generate about the same maximal force of contraction, and the rate of cross-bridge cycling is approximately the same as in skeletal muscle

Ion Transport

• Movement of Na+ ions into a nerve cell during the upstroke of an action potential is an example of facilitated diffusion
• Simple diffusion, primary active transport, co-transport, and counter-transport are different types of transport

Synaptic Transmission

• Inhibitory synapse is a type of synapse where the activity of the presynaptic neuron leads to a decrease of the activity of the postsynaptic cell
• Axo-somatic synapse, axo-dendritic synapse, axo-axonal synapse, and excitatory synapse are different types of synapses

Action Potential Characteristics

• The all-or-none principle states that a stimulus that is below the threshold will not elicit an action potential, while a stimulus that is above the threshold will do so, and each action potential has approximately the same magnitude and duration irrespective of the strength of the stimulus
• Safety factor, refractoriness, accommodation, and transmission are different concepts

Parathyroid Hormone

• Decrease in extracellular calcium ion activity below the normal value stimulates the secretion of parathyroid hormone
• Calcitonin, respiratory acidosis, and PTH-releasing hormone from the hypothalamus do not stimulate the secretion of parathyroid hormone