Microscopic Skeletal Muscle Anatomy Flashcards
1
Q
Sarcomere
A
Contractile unit of skeletal
muscle
2
Q
Sarcoplasm
A
Cytoplasm of the muscle fiber
3
Q
Sarcoplasmic reticulum (SR)
A
- Specialized smooth endoplasmic reticulum
- Stores and releases calciumin to the sarcoplasm
- The expanded ends of the SR are called terminal cisternae
4
Q
Sarcolemma
A
Plasma membrane of the muscle fiber
5
Q
Transverse tubules (T-tubules)
A
Involutions of the sarcolemma into the sarcoplasm
6
Q
Myofibrils
A
- Rod-like structures that run the entire
length of the muscle fiber - Occupy 80% of the volume of a muscle fiber
7
Q
Myoglobin
A
- Protein that binds and stores oxygen
- Located in the sarcoplasm
- Pigmented red
8
Q
Inclusions
A
- Glycosomes – granules of stored glycogen
(provide glucose during muscle cell activity)
9
Q
Mitochondria
A
Perform aerobic respiration to produce energy for muscle activity
10
Q
Nucleus
A
Organelle within cell that contains chromosomes
11
Q
A band
A
- Region of thick filaments * Dark bands
12
Q
H zone
A
- Middle region of the A band (doesn’t overlap with the thin filaments)
13
Q
I band
A
- Region of thin filaments (doesn’t
overlap with the A band) - Light bands
14
Q
Z disc
A
- Anchors the thin filaments
- Define the boundaries between sarcomeres
15
Q
M line
A
- Anchors the thick filaments
- Bisects the sarcomere
16
Q
Axon terminals
A
Terminals of the motor neuron that make contact with the skeletal muscle
17
Q
Triad
A
Composed of a transverse tubule between two terminal cisternae
18
Q
Actin
A
Proteins that make up microfilaments
