Musculoskeletal System Flashcards
1
Q
Sarcomere?
A
- contractile unit of the fibers of skeletal muscle
- contains thin actin and thick myosin filaments
2
Q
What is the length of a sarcomere?
A
z line to z line
3
Q
Initiation of contraction?
A
depolarization of a neuron leads to an action potential
4
Q
Sarcomere shortening?
A
- sarcoplasmic reticulum releases Ca 2+
- Ca 2+ binds to troponin on the actin filament
- Tropomyosin shifts, exposing myosin binding sites
- Myosin binds, ATPase activity allows myosin to pull thin filaments towards the center of the H zone, and then ATP causes dissociation
5
Q
Relaxation?
A
Ca 2+ is pumped back into the sarcoplasmic reticulum
6
Q
Osteoblast?
A
builds bone
7
Q
Osteoclast?
A
breaks down bone
8
Q
Reformation of bone?
A
inorganic ions are absorbed from the blood for use in bone
9
Q
Degradation (resorption) of bone?
A
inorganic ions are released into the blood
