Muscles

Question 1

Properties of skeletal muscle:

Excitability

Answer 1

Muscles have the capacity to respond to nerve stimulation, and contract when needed.

Question 2

Properties of skeletal muscle:

Contractility

Answer 2

Muscles can contract, or shorten. They change in length during the contraction. They can shorten up to 50% of resting length.

Question 3

Properties of skeletal muscle:

Extensibility

Answer 3

Muscles can stretch, or lengthen. Contraction of one muscle often causes extension of another.

Question 4

Properties of skeletal muscle:

Elasticity

Answer 4

A muscle will “spring” back into its original length after being stretched.

Question 5

What are the functions of skeletal muscle?

Answer 5

• Movement of body: skeletal muscles attach to bones via tendons
• posture maintenance: deep slow twitch muscle fibers subconsciously contract to keep the body upright
• heat production: shivering when it’s cold outside

Question 6

What are the structural layers of a skeletal muscle?

Answer 6

From inside to outside:
-Muscle cell(myofiber), surrounded by
Endomysium(connective tissue)

-Fascicle(a bundle of myofibers), surrounded by perimysium( connective tissue)

-Muscle( the whole muscle, a bundle of fascicles), surrounded by
Epimysium

Question 7

What are the parts of a muscle cell?

Answer 7

Sarcolemma= cell membrane of a muscle cell
Sarcoplasm=cytoplasm of a muscle cell
T-tubule= tubular invagination of sarcolemma that conducts never impulses deep into the muscle cell 
Sarcoplasmic reticulum(SR)=smooth ER that stores calcium 
Terminal cisterna-the enlarges ends of the SR that border the T-tubule 
Triad= 2 terminal cisterna + the T-tubule that runs between them. The triad setup is important for stimulating the release of calcium from the SR by an incoming nerve impulse down the T-tubule 
Synapse= site of communication between a neuron and: 1) another neuron 2) a muscle 3) a gland