Steps of Skeletal Muscle Contraction

Questions and Answers

What happens in the second step of skeletal muscle contraction?

Ach binds to Ach receptor on muscle cell.

What occurs during the fifth step of skeletal muscle contraction?

Calcium is released from the sarcoplasmic reticulum.

What is the action in the ninth step of skeletal muscle contraction?

ATP binds myosin heads and heads release the actin filaments.

What occurs in the fourth step of skeletal muscle contraction?

Action potential travels down the sarcolemma and enters the t-tubules. Signup and view all the answers

What happens in the first step of skeletal muscle contraction?

Somatic motor neuron releases Ach (neurotransmitter). Signup and view all the answers

What is the sixth step of skeletal muscle contraction?

Calcium binds to troponin on the thin filament and it moves, then tropomyosin moves. Signup and view all the answers

Describe the seventh step of skeletal muscle contraction.

ATP binds to myosin heads on a thick filament, and the heads cock back and bind to the actin molecules on the thin filament. Signup and view all the answers

What takes place in the tenth step of skeletal muscle contraction?

Calcium is pumped back into the sarcoplasmic reticulum. Signup and view all the answers

What action is performed in step eight of skeletal muscle contraction?

Myosin heads ratchet and pull the thin filaments toward the M-line (middle of the sarcomere). Signup and view all the answers

What happens in the third step of skeletal muscle contraction?

Ion channel opens and positively charged sodium ions rush across the membrane. Signup and view all the answers

Study Notes

Steps of Skeletal Muscle Contraction

Somatic motor neuron releases acetylcholine (ACh), a neurotransmitter, initiating the contraction process.
ACh binds to ACh receptors on the muscle cell membrane, triggering subsequent reactions.
An action potential is generated and travels down the sarcolemma, then enters t-tubules, facilitating muscle fiber activation.
Ion channels open, allowing positively charged sodium ions to rush into the muscle cell, further propagating the action potential.
Calcium ions are released from the sarcoplasmic reticulum, a crucial step for muscle contraction.
Calcium binds to troponin on the thin filaments, causing a conformational change that moves tropomyosin, exposing binding sites for myosin.
ATP binds to myosin heads on thick filaments, which cocks the heads back and allows them to bind to actin molecules on thin filaments.
Myosin heads ratchet, pulling thin filaments toward the M-line (the center of the sarcomere), resulting in muscle contraction.
As the contraction cycle progresses, ATP binds to the myosin heads again, causing them to release the actin filaments.
Calcium ions are pumped back into the sarcoplasmic reticulum, which is essential for muscle relaxation post-contraction.

Description

This quiz focuses on the sequential steps involved in skeletal muscle contraction. Each step highlights key processes such as the binding of Ach to its receptor, the role of calcium, and the interaction of ATP with myosin heads. Review these essential concepts to enhance your understanding of muscle physiology.