Physiology of muscle

Question 1

Describe the major physiological functions served by skeletal muscle

Answer 1

Execute body movement
Establish & maintain posture
Accomplished by shortening or lengthening distance between points of muscle attachment to bone

Question 2

What are the cellular and sub-cellular structures involved in muscle function?

Answer 2

Contractility
Excitability
Extensibility
Elasticity
Muscle type

Question 3

What is contractility?

Answer 3

ability of a muscle to shorten, accompanied by mechanical force generation:
role in movement

Question 4

What is excitability?

Answer 4

capacity of muscle to respond to stimuli that regulate its state of contraction

Question 5

What is extensibility?

Answer 5

ability to be passively stretched beyond a normal “resting length”

Question 6

What is elasticity?

Answer 6

ability of a muscle to recoil toward original resting length after being stretched

Question 7

What are the passive, elastic elements?

Answer 7

Tendons

Question 8

What are the mechanisms by which the force of contraction of a skeletal muscle may be varied?

Answer 8

Engaging varying numbers of motor units

Alteration in the frequency of stimulation

The length of the muscle prior to arrival of a stimulus to contract

Question 9

What are the causes of muscle atrophy, under either homeostatic or pathologic conditions?

Answer 9

May result from either depressed protein synthesis, enhanced proteolysis, or both.