Q&A Hero

Q: Local potentials are __________, whereas action potentials are __________. A. irreversible; reversible B. self-propagating; local C. graded; all or none D. nondecremental; decremental E. produced by voltage-regulated channels; produced by gated channels

Q: What occurs during hyperpolarization of a neuron membrane? A. Sodium ions are entering the cells B. Sodium ions are leaving the cell C. Potassium ions are entering the cell D. Potassium ions are leaving the cell E. Both sodium and potassium ions are leaving the cell

Q: During the absolute refractory period which of the following is true? A. If a neuron reaches threshold, the action potential goes to completion. B. The neuron fires at its maximum voltage if a stimulus depolarizes the neuron to threshold. C. The signal grows weaker with distance. D. It is possible to trigger a new action potential, but only with an unusually strong stimulus. E. No stimulus of any strength will trigger a new action potential.

Q: A traveling wave of excitation is known as a(n) __________. A. local potential B. graded potential C. action potential D. nerve signal E. depolarizing signal

Q: What would be the best explanation for why myelinated fibers conduct signals faster than unmyelinated fibers? A. There are no internodes in unmyelinated fibers. B. There are more internodes in unmyelinated fibers. C. Facilitated diffusion of sodium and potassium is faster in myelinated fibers. D. Active transport of sodium and potassium is faster in myelinated fibers. E. Diffusion of ions along the axoplasm is faster.

Q: Conduction of a nerve impulse would be the fastest in which of the following? A. A large diameter myelinated fiber B. A small diameter myelinated fiber C. A large unmyelinated fiber D. A small unmyelinated fiber E. A small fiber with multiple Schwann cells

Q: In order to regenerate, a peripheral nerve fiber must have which of the following? A. All dendrites intact B. At least half the length of the fiber intact C. At least the entire axon and neurilemma intact D. The soma and at least some neurilemma intact E. At least part of the soma intact

Q: Which of the following ions has the greatest influence on the resting membrane potential? A. Sodium B. Chloride C. Calcium D. Phosphate E. Potassium

Q: Where do most local potentials form in a neuron? A. The dendrites B. The somas C. The axon hillock D. The trigger zone E. The Schwann cells

Q: In a neuron, the opening of sodium gates typically leads to __________. A. repolarization of the plasma membrane B. hyperpolarization of the plasma membrane C. depolarization of the plasma membrane D. drifting of plasma membrane voltage toward a more negative value E. plasma membrane voltage returning to the resting membrane potential

Q: Which of the following will cause the plasma membrane to hyperpolarize when at its RMP? A. An inflow of sodium B. An inflow of potassium C. An inflow of calcium D. An inflow of chloride E. An outflow of chloride

Q: Local potentials are __________, meaning they vary in magnitude according to the strength of the stimulus. A. stabile B. graded C. self propagating D. excitatory E. inhibitory

Q: An inhibitory local potential causes which of the following? A. Depolarization of the plasma membrane B. Hyperpolarization of the plasma membrane C. Repolarization of the plasma membrane D. Neutralization of the plasma membrane E. Drifting of the membrane potential towards the resting membrane potential

Q: While a neuron membrane is depolarizing its __________. A. chloride gates are partially open B. chloride gates are fully open C. potassium gates are fully open D. sodium gates are partially open E. sodium gates are fully open

Q: Which glial cell is found wrapped around nerve fibers in the PNS? A. Oligodendrocytes B. Schwann cells C. Satellite cells D. Nodes of Ranvier E. Ependymal cells

Q: In which part of a neuron is the postsynaptic membrane usually found? A. Synaptic knob B. Axon C. Dendrite D. Perikaryon E. Axon collateral

Q: What is the primary site on a neuron for receiving signals from other neurons? A. The synaptic knobs B. The axons C. The axon collaterals D. The somas E. The dendrites

Q: Which cells form myelin in the spinal cord? A. Schwann cells B. Astrocytes C. Satellite cells D. Oligodendrocytes E. Microglia

Q: A myelin sheath is composed primarily of __________. A. lipids B. carbohydrates C. glycoproteins D. proteins E. polysaccharides

Q: Memories are formed by neural pathways of modified synapses.

Q: The __________ division carries signals to the smooth muscle in the large intestine. A. visceral sensory B. somatic sensory C. visceral motor D. somatic motor E. afferent

Q: The __________ division tends to prepare the body for action. A. sensory afferent B. motor afferent C. somatic motor D. parasympathetic E. sympathetic

Q: Which of the following are effectors? A. Receptors B. Stimuli C. Reflexes D. Glands E. Sense organs

Q: What is another name for the autonomic nervous system? A. Visceral sensory division B. Somatic sensory division C. Visceral motor division D. Somatic motor division E. Central nervous system

Q: Nerves are __________ of the nervous system. A. organs B. tissues C. organ systems D. organelles E. cells

Q: Some __________ neurons are specialized to detect stimuli, whereas __________ neurons send signals to the effectors of the nervous system. A. efferent; afferent B. afferent; efferent C. motor; sensory D. efferent; association E. afferent; association

Q: About 90% of the neurons in the nervous system are __________ neurons. A. sensory B. motor C. afferent D. efferent E. association

Q: What is the most common type of neuron? A. Multipolar B. Bipolar C. Unipolar D. Anaxonic E. Dendritic

Q: The term "nerve fiber" refers to a(n) __________. A. nerve cell B. organelle in nerve cells C. organ D. axon E. bundle of macromolecules in nerve cells

Q: Most metabolic and regulatory functions in a neuron happen where? A. The axon B. The soma C. The dendrites D. The axon hillock E. The Schwann cell

Q: Acetylcholine triggers the synthesis of the second messenger cAMP only in neurons of the PNS.

Q: Nitric oxide (NO) acts as a neuromodulator by altering synaptic function.

Q: Any two EPSPs will override one IPSP.

Q: The minimum stimulus needed to cause muscle contraction is called the __________. A. threshold B. latent period C. twitch D. motor unit E. innervation

Q: If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be __________. A. fatigue B. spasm C. incomplete tetanus D. complete tetanus E. flaccid paralysis

Q: Which of the following is true concerning isotonic eccentric contraction? A. The muscle shortens but tension remains constant. B. The muscle lengthens but tension remains constant. C. The muscle tenses and shortens. D. The muscle tenses but length remains unchanged. E. The muscle lengthens and tension declines.

Q: The nervous system employs exclusively electrical means to send messages, whereas the endocrine system communicates by means of chemical messengers.

Q: Most neurons have multiple dendrites.

Q: Neurons move material away from the soma by retrograde transport.

Q: Unipolar neurons have only a single process leading away from the soma.

Q: Oligodendrocytes serve the same purpose in the CNS that satellite cells do in the PNS.

Q: Ependymal cells line the inner cavities of the CNS.

Q: In the brain, neurons are more abundant than neuroglia.

Q: An action potential never occurs in dendrites. TRUE Gradable: automatic 9. When a neuron is stimulated, Na+ gates open and allow Na+ to exit the cell. FALSE Gradable: automatic

Q: In a myelinated fiber, only the initial segment in the trigger zone has voltage-regulated channels.

Q: Norepinephrine is a monoamine.

Q: Which of the following is an accurate comparison of skeletal muscle to smooth muscle? A. Smooth muscle contracts more slowly but relaxes more rapidly. B. Smooth muscle contracts more rapidly but relaxes more slowly. C. Smooth muscle contracts and relaxes more slowly. D. Smooth muscle consumes more ATP to maintain a given level of muscle tension. E. Smooth muscle depends on a nerve fiber to supply the calcium needed for contraction.

Q: In order for muscle to continue contracting during anaerobic fermentation, which of the following is essential? A. Cholinesterase inhibitors B. Protease C. Myokinase D. Acetylcholinesterase E. Acid phosphatase

Q: Some smooth muscle is autorhythmic.

Q: Which of the following marks the boundaries of a sarcomere? A. I bands B. H bands C. Z discs D. M lines E. A bands

Q: Which of the following is predominately made up of myosin? A. G actin B. F actin C. The thin filament D. The thick filament E. The elastic filament

Q: Which of the following contains overlapping thick and thin filaments? A. A band B. H band C. I band D. M line E. Z discs

Q: Which of the following is not a purpose of the excess postexercise oxygen consumption (EPOC) in muscle? A. To neutralize carbon dioxide buildup B. To replenish the phosphagen system C. To oxidize lactic acid D. To serve elevated metabolic rate E. To restore resting levels of ATP and CP

Q: Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source? A. Skeletal muscle B. Smooth muscle C. Cardiac muscle D. Skeletal and smooth muscle E. Smooth and cardiac muscle

Q: Which muscle(s) can contract without the need for nervous stimulation? A. Skeletal muscle only B. Smooth muscle only C. Cardiac muscle only D. Smooth and cardiac muscle E. Skeletal, smooth and cardiac muscle

Q: 80% of the lactic acid produced by skeletal muscle is converted to pyruvic acid by the __________. A. kidneys B. liver C. muscle tissue D. sarcoplasmic reticulum E. neuromuscular junction

Q: During muscle contraction, a single myosin head consumes ATP at a rate of about __________ ATP per second. A. 1 B. 3 C. 5 D. 7 E. 9

Q: Shortening a muscle while it maintains constant tension is called __________. A. complete tetanus B. incomplete tetanus C. an isokinetic contraction D. an isometric contraction E. an isotonic contraction

Q: Which fibers are primarily responsible for producing lactic acid? A. Type I slow oxidative fibers B. Type IIA intermediate glycolytic fibers C. Type IIB fast glycolytic fibers D. Type I slow-twitch fibers E. Red fibers

Q: Michael Jordan was arguably the best player in professional basketball history. Scientifically, one would expect him to have highly developed __________ fibers. A. red B. white C. intermediate D. fast twitch E. slow oxidative

Q: Where would you expect to find numerous gap junctions in muscular tissue? A. The sarcoplasmic reticulum of skeletal muscle B. The A bands of skeletal and cardiac muscle C. The sarcolemma of skeletal muscle D. The intercalated discs of cardiac muscle E. Multiunit smooth muscle

Q: Why is the contraction strength of smooth muscle relatively independent of its resting length? A. It gets nearly all of its Ca2+ from the extracellular fluid. B. It does not have intercalated discs. C. It does not have sarcomeres. D. It is regulated by a length-tension relationship. E. It is involuntary muscle.

Q: An isometric contraction does not change muscle length.

Q: A volleyball player depends on the gastrocnemius muscles for plantar flexion, whereas a marathon runner depends more on the soleus muscles for the same action. What characteristic of the soleus muscles makes this so? A. They have smaller mitochondria. B. They have more glycogen in them. C. They don't have as many blood capillaries per gram of tissue. D. They make more use of aerobic respiration. E. They break ATP down to ADP and Pi faster.

Q: Why does one continue to breathe heavy after rigorous physical activity has stopped? A. The diaphragm is waiting for its acetylcholine to run out. B. The body requires more oxygen to restore levels of ATP and creatine phosphate. C. The lungs can't stop breathing until the heart rate slows down. D. Myosin heads need more oxygen to fully detach from actin. E. The kidneys require oxygen to dispose of excess lactic acid.

Q: In skeletal muscle, the term that describes the alternating light and dark bands is ___________. A. strabismus B. striations C. tetanus D. myofibrils E. myoblasts

Q: The training regimen of a competitive weight lifter is designed partly to __________. A. convert certain parallel muscles into stronger pennate muscles B. increase the average number of myofibrils per muscle fiber C. convert white muscle tissue to red muscle D. increase the size of his motor units E. lower the threshold for muscle excitation

Q: All muscle types will respond to an electrical stimulus because all muscle cells are _________. A. excitable B. contractile C. striated D. involuntary E. isometric

Q: Skeletal muscle is called ___________, because it is usually subject to conscious control. A. excitable B. contractile C. striated D. voluntary E. isometric

Q: When a skeletal muscle lengthens, its __________ helps resist excessive stretching and subsequent injury to the muscle. A. thick filaments B. collagen C. actin D. troponin-tropomyosin complex E. varicosities

Q: Extensibility refers to the ability of a muscle to stretch.

Q: A dark band formed by parallel thick filaments that partly overlap the thin filaments is known as an H band.

Q: The sarcoplasmic reticulum is the smooth endoplasmic reticulum of a muscle fiber.

Q: Clinically, dystrophin is the most important noncontractile protein to occur in muscle fibers.

Q: The sliding filament theory of muscle contraction has emerged from research only in the last 10 to 15 years.

Q: A deficiency of acetylcholine receptors leads to muscle paralysis in myasthenia gravis.

Q: A skeletal muscle generates the greatest tension when it is __________. A. greatly stretched before being stimulated B. partially stretched before being stimulated C. fully relaxed before being stimulated D. well-rested and low in creatine phosphate E. high in lactic acid concentration

Q: When acetylcholinesterase outlasts the release of acetylcholine from the synaptic vesicles, the skeletal muscle __________. A. contracts B. gets stronger C. relaxes D. releases Ca++ E. opens its Na+ channels

Q: The transfer of phosphate from CP to ADP is catalyzed by __________. A. myokinase B. creatinine C. cAMP D. creatine kinase E. ATP

Q: What happens when acetylcholine stimulates its receptors in the neuromuscular junction? A. The release of Ca2+ from the sarcoplasmic reticulum decreases. B. The permeability of the sarcolemma to Na+ increases. C. The positive charge on the sarcolemma decreases. D. The threshold of the muscle fiber lowers. E. The inhibitory effect of acetylcholinesterase is overridden.