Chapter 10 (Muscular Tissue III)

Question 1

Nerve and Blood Supply (Skeletal Muscle Tissue)

Answer 1

Neurons that stimulate skeletal muscle to contract are somatic motor neurons
The axon of a somatic motor neuron typically branches many times
Each muscle fiber is in close contact with one or more capillaries

Question 2

Skeletal Muscle Nerve Supply

Answer 2

Somatic Motor neuron

Sarcolemma

Question 3

Skeletal Muscle Growth and Development

Answer 3

Skeletal muscle fibers form in the embryo by fusion of myoblasts
Cells are therefore multinucleated
The number of skeletal muscle fibers is set before you are born
Most of these cells last a lifetime
Muscle growth occurs by hypertrophy, an enlargement of existing muscle fibers
Testosterone and human growth hormone stimulate hypertrophy
Satellite cells retain the capacity to regenerate damaged muscle fibers

Question 4

Skeletal Muscle Tissue Microanatomy

Answer 4

Sarcolemma, Transverse (T tubules), Sarcoplasm, Myofibrils, Filaments, Sarcomeres, Sarcoplasmic reticulum (SR), Terminal Cisterns

Question 5

Sarcolemma

Answer 5

The plasma membrane of a muscle cell

Question 6

Transverse (T tubules)

Answer 6

Tunnel in the plasma membrane

Muscle action potentials travel through the T tubules

Question 7

Sarcoplasm (Cytoplasm of a muscle fiber)

Answer 7

Sarcoplasm includes glycogen used for synthesis of ATP and a red-colored protein called myoglobin which binds oxygen molecules
Myoglobin releases oxygen when it is needed for ATP production

Question 8

Myofibrils

Answer 8

Thread-like structures which have a contractile function

Question 9

Filaments

Answer 9

Lie in the myofibrils
Function in the contractile process
Two types of filaments (Thick and Thin)
There are two thin filaments for every thick filament

Question 10

Sarcomeres

Answer 10

Compartments of arranged filaments

Basic functional unit of a myofibril

Question 11

Sarcoplasmic reticulum (SR)

Answer 11

Membranous sacs which encircles each myofibril
Stores calcium ions (Ca++)
Release of Ca++ triggers muscle contraction

Question 12

Terminal Cisterns

Answer 12

Dilated end sacs of the sarcoplasmic reticulum that lie adjacent to the transverse tubules
A triad consists of a transverse tubule and the two cisterns that lie on either side of it