lecture 2 part 2
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lecture 2 part 2

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Questions and Answers

Which characteristic of skeletal muscle makes up approximately 40% of body mass?

Protein storage and metabolism

What is one of the functions of skeletal muscle besides generating force through contraction?

Insulation against cold

How does the intrinsic muscle structure influence muscle force output?

By affecting the amount of tension the muscle can generate

What is the primary function of the motor neuron in relation to skeletal muscle?

<p>Generating electrical impulses for muscle contraction</p> Signup and view all the answers

How does the neuromuscular junction contribute to excitation-contraction coupling in skeletal muscle?

<p>By transmitting signals from the motor neuron to the muscle fiber</p> Signup and view all the answers

What is the term used to describe the invaginations of the sarcolemma at regular intervals in the skeletal muscle structure?

<p>T-tubules</p> Signup and view all the answers

Which of the following is not a component of the close interaction in the skeletal muscle structure?

<p>Myofibrils</p> Signup and view all the answers

Which muscle architecture has a greater overall force capacity due to a larger Physiological CSA?

<p>Multipennate muscle</p> Signup and view all the answers

What does the correction factor cosβ account for in the force applied to the tendon in muscles?

<p>Angle of attachment to tendon</p> Signup and view all the answers

Which component contributes to the physical proximity in the skeletal muscle structure by providing calcium regulatory sites for contraction?

<p>Sarcoplasmic reticulum</p> Signup and view all the answers

What is the term used to describe muscles that have fibers running at an oblique angle to the tendon?

<p>Pennated muscles</p> Signup and view all the answers

What is the function of tropomyosin in muscle contraction?

<p>Regulates the exposure of the myosin binding site for crossbridge cycling</p> Signup and view all the answers

Which structure in the sarcomere serves as an anchor for regulatory proteins?

<p>Z line</p> Signup and view all the answers

What is the primary function of titin in muscle structure?

<p>Anchors thin filaments to the Z-line</p> Signup and view all the answers

Which component is considered the functional unit of skeletal muscle?

<p>Sarcomere</p> Signup and view all the answers

What is the role of troponin in muscle contraction?

<p>Regulates the exposure of the myosin binding site for crossbridge cycling</p> Signup and view all the answers

Where do regulatory proteins troponin and tropomyosin primarily act within the sarcomere?

<p><em>Z line</em></p> Signup and view all the answers

What is the relationship between pennation angle and P-CSA in muscles?

<p>Greater pennation angle leads to greater P-CSA</p> Signup and view all the answers

What is the trade-off associated with having a greater pennation angle in muscles?

<p>Smaller fascicle length</p> Signup and view all the answers

How does muscle fibre type composition affect muscle contraction?

<p>Faster contraction speed with a higher proportion of fast-twitch fibres</p> Signup and view all the answers

What is the primary determinant of muscle force output according to the text?

<p>Cross-sectional area (CSA)</p> Signup and view all the answers

How are muscle fibre types classified in humans according to the text?

<p>I, IIA, and IIX</p> Signup and view all the answers

How does a change in muscle length impact fibre length?

<p>Greater change in fibre length than muscle length</p> Signup and view all the answers

Why do variations in muscle shapes and architecture, such as fusiform, non-pennate, and multipennate muscles exist?

<p>To optimize muscle function based on different force and shortening requirements.</p> Signup and view all the answers

How does the small loss of force per fiber in muscles with greater pennation angle translate into an advantage?

<p>It results in a significant increase in packing density and overall greater force potential.</p> Signup and view all the answers

What is the primary function of the motor neuron in relation to skeletal muscle?

<p>The primary function of the motor neuron is to transmit neural signals from the central nervous system to the muscle fibers, initiating muscle contraction.</p> Signup and view all the answers

What is the role of regulatory proteins troponin and tropomyosin in the sarcomere?

<p>Regulate the exposure of the myosin binding site for crossbridge cycling in response to calcium.</p> Signup and view all the answers

How do thick and thin filaments interact to generate force in the sarcomere?

<p>Through the crossbridge force generation mechanism.</p> Signup and view all the answers

What is the significance of the Z line in the sarcomere structure?

<p>It serves as an anchor for many regulatory proteins, notably thin filaments.</p> Signup and view all the answers

What is the primary function of titin in the muscle structure?

<p>Titin serves as an anchor, linking the thick filaments to the Z-line and providing elasticity to the sarcomere.</p> Signup and view all the answers

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