Question

In: Anatomy and Physiology

Question 1. which if the following does not occur during the "Excitation" of a skeletal muscle?...

Question 1. which if the following does not occur during the "Excitation" of a skeletal muscle?

A. The myosin head binding site on actin is exposed

B. ATPase on myosin heads split ATP

C. The passive force of contraction increases

D. The cell membrane depolarizes

Question 2. Which if the following does not occur during skeletal muscle contraction?

A. titin fibers compress

B. Actin and myosin shorten

C. sacromeres shorten

Question 3. Which of the following describes the relationship between the type of metabolism used by skeletal msucle fiber and its resistance to fatigue?

A. muscle fibers that habe a high glycolytic ability do not fatgue

B. muscle fibers with a high oxidative capacity have a high resistance to fatigue

C. Muscle fibers with a low oxidative capacity are resistant to fatgue

Question 4. The strength of a muscle contraction is determined all of the following except?

A. The number of muscle fibers in a motor unit that contract

B. the frequncy of a stimuli applied to a muscle

C.the number of motor units recruited

Question 5. what can you conclude about postural muscles?

A. These muscles contain slow twitch muscles can sustain contraction while resisting fatigue

B. These muscles contain fast oxidative muscle fiber that have a low resistance to fatigue

C. These muscles contain fast twitch muscle fibers that can correct posture changes rapidly

Expert Solution

Answer 5. Option (A) is the correct option. Postural muscles - as the name suggest these muscle play an important role in maintaining posture for long time. The postural muscles have slow twitch muscles fibres which provide them strength for longer time and prevent them from getting fatigue.

But, Fast oxidative muscle fibres are those which consume more energy so that they can contract rapidly and are easily fatigued.

But, Fast twitch muscle fibres can be easily fatigued as they contract fast so they are not good for maintaining Posture.

Hence option b,c are incorrect and are not qualities of postural muscles.

Answer 4. The strength of muscle contraction depends on

- The number of muscles contracting

- The speed of contraction of muscle

- frequency &strength of stimulus

- what amount of stretching has been occurred.

Which means option A&B are used to measure the strength of muscle.

Hence option (c) is correct answer.

Answer 3. Option. C Describes the relation between relation between type of metabolism used by the skeletal muscle fiber and its resistance to fatigue because the low oxidative capacity mucle fibres have good supply of oxygen like skeletal muscles & have slow twitch muscle fibres due to which they don't get fatigue easily.

But fast oxidative and glycolytic muscle fibres fatigue easily.

Answer 2. Option B as myosin length does not shorten while muscle contraction.

Answer . 1 option (C) is the correct answer as myosin binding site on the actin globular does get exposed,membrane depolarization occurs to enter Ca++ ions , Atp splits on myosin head.

Sydney Mullin answered 1 year ago

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