Unit 3, Lecture 4

Front

What is the actin represented by in muscle fibers?

Back

C

Front

What is the gap between the motor neuron and the muscle fiber at the neuromuscular junction called?

Back

Synaptic cleft

Front

What are the thick myofilaments in muscle fibers called?

Back

Myosin

Front

What is the plasma membrane of a muscle fiber called?

Back

Sarcolemma

Front

How are contractions generated in muscle fibers?

Back

By the sliding of thin filaments past thick filaments.

Front

What is the role of acetylcholine in muscle contraction?

Back

It is a neurotransmitter that transmits signals from motor neurons to muscle fibers.

Front

What is the function of the sarcoplasmic reticulum in muscle cells?

Back

It stores calcium ions and releases them during muscle contraction.

Front

What is a sarcomere?

Back

The basic contractile unit of muscle fibers, defined by the area between two Z lines.

Front

What is tropomyosin's role in muscle contraction?

Back

It blocks the binding sites on actin filaments, preventing contraction until calcium ions bind to troponin.

Front

What is the function of troponin in muscle contraction?

Back

It binds calcium ions and causes tropomyosin to move, exposing binding sites on actin.