chapter 9 quiz

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What is the name of the membrane of skeletal muscles?

Epimysium

Endomysium

Sarcolemma (correct)

Perimysium

What protein filaments are responsible for muscle contraction?

Keratin and Collagen

Fibrin and Tropomyosin

Elactin and Fibronectin

Actin and Myosin (correct)

What is the purpose of T-Tubules in skeletal muscle cells?

To store calcium ions

To provide structural support to the cell

To conduct impulses for muscle contraction (correct)

To transport materials within the cell

Which component is responsible for the storage of calcium ions in muscle cells?

Sarcoplasmic reticulum Signup and view all the answers

What is the smallest functional unit of muscle fibers?

Sarcomeres Signup and view all the answers

Which proteins interact during muscular contraction within the myofibrils?

Myosin and Actin Signup and view all the answers

What principle states that all muscle fibers in a motor unit contract together when stimulated?

All or none Principle Signup and view all the answers

What is the main difference between hypertrophy and atrophy in muscles?

Hypertrophy increases the number of myofibrils, while atrophy results in the loss of intracellular contractile proteins. Signup and view all the answers

Which type of muscle fiber is characterized by a smaller diameter, many more mitochondria, and long sustained contractions?

Slow (Red) Fibers Signup and view all the answers

What is the primary reason why the majority of skeletal muscles are fast (white) fibers?

Due to their rapid response to stimulation Signup and view all the answers

What is the function of mitochondria in muscle fibers?

Generate energy for muscle contraction Signup and view all the answers

Which principle describes the recruitment of motor units from smallest to largest as force increases?

'Size principle' Principle Signup and view all the answers

What covers the active site preventing Actin-Myosin interaction?

Tropomyosin Signup and view all the answers

What holds tropomyosin in place and must move to initiate contraction?

Troponin Signup and view all the answers

Which proteins form cross-bridges when interacting with thin filaments during contraction?

F-actin and myosin Signup and view all the answers

What is the term for the change in size of the sarcomere during muscle contraction?

Z line shift Signup and view all the answers

What term is used to describe a single motor neuron and all the muscle fibers it controls?

Motor unit (MU) Signup and view all the answers

What determines the force generated during skeletal muscle contraction?

Number of motor units stimulated Signup and view all the answers