Muscle Metabolism Flashcards
1
Q
3 types of muscles are
A
- skeletal- myofibers
- cardiac- myocites
- smooth
2
Q
how do skeletal muscles develop
A
fusion of mesodermal cells (myoblasts and embryonic cells)
3
Q
what are the 2 kinds of myofilaments
A
- thin one called actin
- thick ones called myosin
4
Q
what forms the terminal cisternae?
A
the sarcoplasmic reticulum
5
Q
the SR is right in which Ca binding protein
A
- calsequestrin
6
Q
what is a triad made of?
A
1T tubule and 2 Terminal cisternae
7
Q
what is the contractile unit of skeletal muscle
A
the sarcomere
8
Q
what are the components of a thin filament?
A
- F actin:2 twisted rows (chains) made of polymers of F actin protomers (42 kDa each) that extend in opposite directions
from the Z-line. the active sites on F actin strands bind to myosin - Nebulin: provides structural support
- tropomyosin: stabalizes F actin
- troponins: −globular proteins of three major types: Tn-T (tropomyosin-binding), Tn-C (calcium-binding), Tn-I (inhibitory
subunits)
−Ca2+ binding to Tn-C, a calmodulin-like protein, induces changes in Tn-I which impair the interaction between
tropomyosin and actin, exposing the myosin-binding sites on F actin and allowing actin-myosin interactions - alpha and beta actinins: stabilization of f actin and anchor it the Z line
9
Q
what are the 2 ready to use energy reservoirs
A
- ATP
- CP: creatine phosphte
10
Q
what are the 2 ways that muscle cells produce ATP
A
- aerobic metabolism of FA in mitochondria
- anaerobic glycolysis in cytoplasm
11
Q
what is the function of AMPK
A
- activates metabolic breakdown
pathways that generate ATP while inhibiting biosynthetic pathways that use
ATP - a subunit contains a Ser/Thr protein kinase domain, and the g subunit
contains sites for allosteric activation by AMP and inhibition by ATP. - must be phosphorylated to become active
12
Q
AMPK promotes
A
FA oxidation and glucose uptake
13
Q
what are the 3 types of muscle fibers
A
- fast: fatigue quickly
- slow: contain myoglobin
- intermediate: slowest to fatigue
