Human Anatomy (3)

What do ball-and-socket joints do?

Allow for rotational movement

What do hinge joints do?

Permit motion in one plane

What do pivot joints do?

Enable rotation around a single axis

What do gliding joints do?

Allow bones to glide past one another

What do saddle joints do?

Permit movement in two planes

What do condyloid joints do?

Allow angular movement but NO rotation

What is the cardiac muscle?

Involuntary muscle found in the heart.

What does the cardiac muscle do?

Contracts rhythmically to pump blood.

What does skeletal muscle do?

Performs voluntary muscle contractions attached to bones for movement.

How does the skeletal muscle fatigue?

Fatigues MORE QUICKLY than other types of muscles.

What is smooth muscle?

Muscle that allows vasoconstriction and vasodilation found in walls of hollow organs.

What is the "all or none" principle?

When a muscle receives the stimulus to contract, it will contract fully or not at all.

What does a motor unit consist of?

A motor neuron and the muscle fibers it innervates.

The motor unit is essential for:

Muscle contraction

What are myofibrils?

Contractile components of a muscle cell

What are myofibrils composed of?

Sarcomeres which contain actin and myosin filaments

What is a sarcomere?

functional unit of muscle cell contraction

What does a sarcomere do?

Shortens during contraction to produce force