Exam 6: The Muscular System

Using the figure above, identify the parts of the sarcomere. A) sarcomere B) actin filament C) myosin filament D) Z-line 14) Label A represents a(n) ________. 15) Label B represents a(n) ________ 16) Label C represents a(n) ________. 17) Label D represents a(n) ________.

Cardiac muscle differs from skeletal muscle in that

In which one of the following would one expect to find motor units made up of only a few muscle cells?

Slow-twitch fibers contain many mitochondria and are well supplied with blood vessels, and can make ATP as they need it.

Muscle cells are located in every organ in the body except the stomach and are essential for any activity that requires movement.

When an electrical impulse traveling along a motor neuron arrives at a neuromuscular junction

Contraction of a skeletal muscle cell is initiated by the

A muscle is arranged in bundles of muscle fibers, called ________.

Which sequence lists the structures from largest, most inclusive, to smallest?

In the absence of ATP, a contracted muscle can't relax.

In skeletal muscle, potassium ions are stored in the sarcoplasmic reticulum.

Muscle cells produce lactic acid when they have an inadequate supply of

Since contraction of the hamstrings causes the knee to bend and contraction of the quadriceps causes the knee to extend, these muscles are said to be ________.

In order for a muscle contraction to occur, cross-bridges must form between which one of the following structures within a muscle cell?

According to the sliding filament mechanism, during a muscle contraction, myosin pulls actin filaments toward the center of a sarcomere, causing the entire sarcomere to shorten.

As the rate of stimulation of motor units of a muscle increases, muscle force increases. This process is known as ________.

The portion of a myofibril from one Z-line to the next is a(n) ________.

The process of activating more motor units when more force must be exerted is called ________.

A complete cycle of contraction and relaxation of muscle cells due to stimulation by a motor neuron is called a muscle ________.

Muscle contraction accounts for over 75% of the heat generated by the body.