Physiology 1021 Study Guide - Midterm Guide: Alpha Motor Neuron, Golgi Tendon Organ, Parasympathetic Nervous System

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1. The sympathetic nervous system:
(A) does not innervate salivary glands
(B) has its cell bodies within the sacral spinal cord
(C) has an important function in maintaining blood flow
(D) is predominantly activated immediately after a meal
2. The adrenal medulla:
(A) is innervated by preganglionic neurons of the parasympathetic nervous system
(B) releases catecholamines directly into circulation
(C) have specialized cells that release acetylcholine into blood vessels
(D) receives innervation from sacral preganglionic neurons
3. The stretch reflex:
(A) is activated in response to increasing muscle tension
(B) activated by Golgi tendon organs
(C) is activated by activation of muscle spindles
(D) mediated by 1b afferent fibres to the spinal cord
4. Reflex arcs involve all of the following EXCEPT:
(A) a synapse
(B) a receptor
(C) an efferent neuron
(D) the length of the nerve pathway
5. Gamma motor neurons innervate:
(A) extrafusal muscle fibers
(B) the myofibrils
(C) muscle spindles (intrafusal muscle fibres)
(D) smooth muscle cells
7. The following statements are correct EXCEPT:
(A) the dorsolateral corticospinal pathway is the main crossed descending motor pathway
(B) the ventromedial corticospinal pathway innervates alpha motor neurons bilaterally
(C) the motor cortex is found within the parietal lobe
(D) the motor cortex is separated from the somatosensory cortex by the central sulcus
8. The motor cortex has certain body parts
having a greater representation than others
on it. This is due to:
(A) a greater density of motor units found within those specific body parts
(B) larger motor units found within those specific body parts
(C) the overall size of the body part
(D) a higher number of muscle fibers innervated by alpha motor neurons in the body part
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9. Which of the following statements about the skeletal muscle is NOT CORRECT?
(A) each actin molecule has a binding site for myosin
(B) the head unit of a myosin molecule contains a binding site for actin and troponin
(C) troponin is attached to both actin and tropomyosin
(D) when the muscle is contracting, tropomyosin is not covering the myosin binding sites
10. Which of the following muscle structures is the smallest functional unit of a muscle cell?
(A) a single actin molecule
(B) a single myosin molecule
(C) a single myofibril
(D) the sarcomere
11. Which of the following is CORRECT concerning the events in excitation contraction
(A) the action potential spreads out from the neuromuscular junction and propagates over the
sarcoplasmic reticulum
(B) Ca2+, which is stored in T-tubules, is released by the action potential
(C) Ca2+ binds to tropomyosin and pulls troponin off the myosin binding sites
(D) myosin binds to actin forming a crossbridge and a powerstroke occurs
12. Which of the following events takes place at the neuromuscular junction?
(A) when K+ enters the axon terminal, it causes the release of acetylcholine
(B) acetylcholine will diffuse across the synaptic cleft and bind to voltage gated ion channels
which open and fire the action potential on the muscle cell
(C) the entry of Na+ into the end plate region of the muscle cells creates an end plate potential
(D) the acetylcholine is taken back up by the axon terminal and then broken down by the
enzyme choline acetate
14. Which of the following statements about action potentials and skeletal muscle twitches is
(A) the action potential in the motor neuron will cause an action potential on all the muscle cell
it contacts
(B) the action potential that initiates the muscle twitch always last longer than the muscle
contraction itself
(C) like action potentials, muscle twitches cannot be summed
(D) motor units are made up of several motor neurons attached to one skeletal muscle cell
15. Which of the following is NOT a direct function of ATP during muscle contraction
and relaxation?
(A) pumping Ca2+ back in the sarcoplasmic reticulum
(B) releasing Ca2+ from the sarcoplasmic reticulum
(C) energizing the myosin head for the powerstroke activity
(D) breaking the crossbridge between actin and myosin
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