Exam 12: A: Physiology of the Muscular System

A motor neuron plus the muscle fibers to which it attaches is called a motor unit.

Maintaining muscle tone is one of the few examples of a positive feedback mechanism in the body.

A muscle using anaerobic respiration would lower the pH of the blood passing through the muscle.

Isometric contraction is a contraction in which the tone or tension within a muscle remains the same but the length of the muscle changes.

When troponin and calcium combine,it causes actin to shift and allows the myosin to form cross-bridges.

In visceral smooth muscle,gap junctions join individual smooth muscle fibers into large,continuous sheets.

A satellite cell can fuse with myocytes during strength training to make larger muscle fibers.

Because of the elasticity of the muscle fiber,as soon as the contraction stops,the sarcomere goes back to its pre-contraction length.

Treppe is a steep increase in the strength of contractions that can be seen in a series of twitch contractions.

The thin myofilament is myosin,whereas the thick myofilament is actin.

Myosin heads release from the actin molecule when ATP attaches to it.

Actin,troponin,and tropomyosin are present on the thick myofilament.

ATP is made up of adenine,ribose sugar,and three phosphate groups.

Recruitment is the term used to describe the addition of more motor units to allow a muscle to increase its strength of contraction.

Eccentric muscle contractions actually result in the lengthening of the muscle.

As resistance increases,the number of motor units needed to overcome that resistance has to increase.

The following are characteristics that allow muscles to function as they do: excitability,contractility,extensibility,and regulation.

Fibrillation is a tetanic contraction of cardiac muscle.

The result of endurance training is more blood vessels,not more muscle cells.

Cardiac muscle is similar to skeletal muscle in that both form strong,electrically coupled junctions with other fibers.