Muscle Anatomy

Front

What happens to the Z lines during a sarcomere contraction?

Back

The Z lines get closer together.

Front

How many sarcomeres are typically found in a muscle fiber?

Back

A muscle fiber can contain hundreds to thousands of sarcomeres.

Front

What is a myofibril?

Back

A myofibril is a long, thread-like structure made up of sarcomeres, responsible for muscle contraction.

Front

What is the function of the sarcolemma?

Back

The sarcolemma is the cell membrane of a muscle fiber that helps maintain the cell's environment and transmits electrical signals.

Front

What is the role of the sarcoplasmic reticulum?

Back

The sarcoplasmic reticulum stores calcium ions, which are essential for muscle contraction.

Front

What are T-tubules?

Back

T-tubules are extensions of the sarcolemma that penetrate into the muscle fiber, facilitating the transmission of electrical impulses.

Front

What is a muscle fiber?

Back

A muscle fiber is a single muscle cell that can contract and is composed of myofibrils.

Front

What is the basic unit of muscle contraction?

Back

The basic unit of muscle contraction is the sarcomere.

Front

What is the significance of the A band in a sarcomere?

Back

The A band contains thick filaments (myosin) and is the region where muscle contraction occurs.

Front

What is the I band in a sarcomere?

Back

The I band is the region of a sarcomere that contains only thin filaments (actin) and is lighter in appearance.