Muscle Physiology 1-2 Flashcards
What are the 4 specific properties of muscle
- Contractility
- Excitability
- Extensibility
- Elasticity
The ability to contract or shorten
Contractility
the capacity to receive and respond to stimulus
excitability
the ability to be streched
Extensibility
The ability to return to original shape after being streched
Elasticity
What are the 3 types of muscle
- Skeletal
- Smooth
- Cardiac
List the levels of organization of skeletal muscle from outside in.
- Epimysium
- Fascicle
- Perimysium
- Endomysium
- sarcolema
- Muscle fibers
What are the 2 types of muscle fibers?
- Red/Type I/ Slow twich
2. White/ Type II/ Fast twitch
The basic contractile unit of striated muscle fibers
Sarcomeres
What are the 2 types of myofilaments?
- Actin (thin)
2. Myosin (thick)
Specialized ER found in muscle cells
Sarcoplasmic reticulum (SR)
What is the function of SR?
Regulate Calcium storage, release, and reuptake
T/F. the SR is bigger in Red muscle
F. Larger in White muscle
T/F. Red muscle has more mitochondria than white.
T
Allow the PM of the muscle fiber to carry the depolarization of the AP to the interior of the fiber
T-Tubules
Junction between a nerve fiber and muscle cell
Neuromuscular junction
The diffusion potential level across a memb. that exactly opposes the net diffusion of a particular ion through the memb.
Nerst potential
What are the 3 forces that cause diffusion of molecules and ions through a CM?
- Net diffusion rate
- Nerst Potential
- Pressure diff.
What is the resting potential fo nerve fibers when not transmitting signals?
-70mV
What are the 3 factors that determine resting potential?
- diffusion of K through the nerve cell memb.
- diffusion of Na through the nerve cell memb.
- Contribution of the Na/K pump
What allows K to diffuse out of the cell?
K leak channels
What allows Na to diffuse out of cell?
Na leak channels
T/F. the memb. is far less permeable to Na than K.
T
What is the most important contributor to resting potential?
K diffusion
How many ions of sodium and potassium does the Na/K pump pump in and out of the cell?
2K ions in
3Na ions out
how are nerve signals transmitted?
AP
Rapid changes in the memb. potential that spread rapidly along the nerve fiber memb.
AP
What are the 3 stages of an AP?
- Resting
- depolarizing
- repolarizing
Moment before AP begins
Resting stage
Stage of AP where a threshold for the initiation of the AP has been achieved.
Depolarization state
During depolarization is the memb. potential rising in the positive or negative direction?
positive
How does the massive Na influx occur?
Voltage-Gated sodium channels
Stage of AP after the memb. becomes highly permeable to Na ions, and the Na channels begin to close
Repolarization
What channels open during the repolarization stage?
voltage gated K channels
Re-establishment of the normal negative resting potential
Repolarization
What is the Refractory period?
A new AP cannot occur in an excitable fiber as long as the memb. is still depolarized from the preceding AP
the period during which an second AP cannot be elicited
Absolute Refractory Period
