1) Which of these would increase the tension generated in a skeletal muscle? A)
ID: 169907 • Letter: 1
Question
1) Which of these would increase the tension generated in a skeletal muscle?
A) stretching the muscle to very long lengths
B) increasing the frequency of firing in alpha motor neurons innervating the muscle
C) resting the muscle for several weeks
D)switching off fast-glycolytic motor units and activating an equal number of slow-oxidative motor units
E)increasing the amplitude of action potentials in the alpha motor neurons that innervate the muscle
2) John is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest. Jim is a marathon runner who specializes in long, steady runs. Compared to John's muscles, how are Jim's most likely to differ?
A) Jim's muscles will have more glycogen stored in his type IIb muscle fibers.
B) Jim's type IIb fibers will be larger in diameter.
C)Jim's muscles will have less myoglobin in his type I muscle fibers.
D) Jim's muscles will have more mitochondria in his type I and IIa muscle fibers.
E) Jim will have a greater proportion of type II muscle fibers and a lower proportion of type I fibers than John
3) Which of the following statements regarding contraction in skeletal and smooth muscle is TRUE?
A) In skeletal muscle, calcium initiates contraction by binding to troponin, while in smooth muscle calcium initiates contraction by binding directly to myosin.
B) In skeletal muscle, calcium ions bind to a regulatory protein on thin filaments; in smooth muscle, calcium ions bind to a regulatory protein on thick filaments.
C) In skeletal muscle, calcium initiates contraction by binding to troponin, while in smooth muscle calcium initiates contraction by binding to calmodulin.
D)In skeletal muscle, calcium initiates contraction by binding to myosin light-chain kinase, while in smooth muscle calcium initiates contraction by binding directly to tropomyosin.
E) All of the choices are true.
4) Which of the following statements is TRUE with regard to the motor control hierarchy?
A)Neurons of the middle level of the hierarchy integrate afferent information with signals from higher center command neurons to create a motor program--a pattern of neural activity required to properly perform a desired movement.
B)Reflexes that include local-level receptors and muscle fibers cannot occur without input from the higher centers of the motor control hierarchy.
C) The highest level of the hierarchy of motor control includes the frontal lobe cortex, the primary motor cortex, muscle sensory receptors, and the basal nuclei.
D) The highest level of the hierarchy of motor control is composed entirely of areas of cerebral cortex, and its main purpose is to create a conscious plan to move that depends on the initial position of the parts of the body in space. E) The local level of the motor control hierarchy includes the premotor and primary motor regions of the cerebral cortex, as well as the alpha motor neurons and muscle fibers themselves.
5) Which of the following normally occurs when a doctor's reflex hammer taps a patient's patellar tendon?
A) Golgi tendon organs in the patellar tendon stimulate the contraction of extrafusal fibers of extensor muscles.
B) Alpha motor neurons stimulate contraction of intrafusal fibers in extensor muscles.
C) Inhibitory interneurons reduce action potential firing in alpha motor neurons to extrafusal fibers of extensor muscles.
D) Alpha motor neurons stimulate contraction of extrafusal fibers in extensor muscles.
E) Alpha motor neurons that innervate ipsilateral flexor muscles are stimulated
These questions were pulled from a Biology/Physiology exam. PLEASE PLEASE PLEASE, Include an explanation of why the correct answer is a specefic one, I really appreciate that.
thanks
Explanation / Answer
1.A) stretching the muscle to very long lengths
because the more you stretch the more is the tension.
2.B) Jim's type IIb fibers will be larger in diameter
This happens in long stead runs that ib fibers become larger.
3.B) In skeletal muscle, calcium ions bind to a regulatory protein on thin filaments; in smooth muscle, calcium ions bind to a regulatory protein on thick filaments
4.C) The highest level of the hierarchy of motor control includes the frontal lobe cortex, the primary motor cortex, muscle sensory receptors, and the basal nuclei.
The remaining statements are false. Thisis true becaise the motor contains all the parts mentioned in this choice.
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