Physiology- Muscle Flashcards
muscle (19 cards)
Determinants of Muscle Strength:
a) number of fibers recruited b) frequency of fiber stimulation c) initial length of fiber at rest
Pennation of muscle fibers allows:
more fibers in the same volume
Muscles that are better at velocity have (long/short) fiber lengths, and (bigger/smaller) pennation angles.
a) long fibers
b) smaller pennation angle
A large amount of force can be generated from a (large/small) angle of pennation
a large angle of pennation
A sprinter will have more of which fiber type?
a) slow type I
b) fast type IIA
c) fast type IIX
b) fast type IIA
c) fast type IIX
General phases of Muscle repair:
1) Destruction/degeneration phase
2) Inflammatory phase
3) Regeneration phase
4) Remodeling phase
Destruction phase of muscle repair is marked by an influx of:
Macrophages to clean up damage and release chemoattractants (recruit neutrophils and monocytes)
Fibrosis occurs ____ after injury
2-3 weeks
Sarcopenia is:
an age-associated loss of muscle mass
Regeneration phase:
a) ____ migrate to the area to begin repairing damage muscle
b) ____ begin producing a connective tissue scar
a) satellite cells
b) fibroblasts
The regenerative capacity of injured skeletal muscle is often constrained by the formation of:
fibrotic tissue
-leads to chronic injury
Fibrosis is a pathology characterized by accumulation of excess _____
ECM
-increased endomysium and perimysium
Frailty is considered meeting 3 or more of the following criteria:
1) recent weight loss
2) self reported exhaustion
3) weakness (<20% age predicted grip strength)
4) slow walking speed
5) decreased physical activity
Cachexia is different from sarcopenia because:
Cachexia is reduced caloric intake, ↑cytokine and inflammatory marker levels.
Sarcopenia is the loss of satellite cells that help rebuild muscle.
Differences in smooth muscle compared to skeletal muscle:
1) no striations in smooth muscle
2) ratio of thin:thick filaments much higher in smooth muscle
3) involuntary
4) autonomic system regulation
5) graded contraction (not all-or-none)
In smooth muscle, long actin filaments attach to ____
dense bodies
function like Z-disks, arrangement allows smooth muscle to contract even when greatly stretched
Single-unit smooth muscle is found in a)_____,
b)____ link cells to neighboring cells allowing them to behave as a unit
a) uterus, GI tract, bladder
b) gap junctions link these pacemaker cells together (they have intrinsic innervation and autonomic innervation)
How does more Ca2+ affect smooth muscle contraction
More calcium = stronger contraction
