Muscle System

What is the primary function of muscles?

Generate movement, force, and heat.

The gene myostatin controls what aspect of muscles?

Muscle growth.

What happens with a defective myostatin gene?

It does not control muscle growth, leading to excess muscle growth and a 'super strong kid'.

What type of muscle is striated and voluntary?

Skeletal muscle.

Which muscle type is uninucleate and involuntary?

Smooth muscle.

What is the structure that allows action potential to reach the interior of a muscle cell?

T tubule.

What are the main contractile proteins in muscle fibers?

Actin and myosin.

What is the primary energy source for muscle contraction?

ATP.

What is the sliding filament theory?

The sarcomere shortens because actin is pulled inward.

What is rigor mortis?

Stiffening of the body after death due to lack of ATP, causing muscles to remain contracted.

How does muscular dystrophy get inherited?

It is X chromosome linked, more common in males due to their single X chromosome.

What type of muscle surrounds blood vessels and internal organs?

Smooth muscle.

What neurotransmitter is involved in muscle contraction?

Acetylcholine.

What muscle fibers are fast-twitch and what are their characteristics?

Fast-twitch fibers are white, with less myoglobin and less mitochondria, and are fast in speed.

Define a motor unit.

A motor neuron plus the muscle fibers innervated by the axon terminals of the motor neuron.

What condition is characterized by nerve damage affecting facial muscles?

Bell’s Palsy.