muscle, kidney, brain, adipose tissue Flashcards
structure of a muscle fiber
myofiber(red, white, intermed(heart) -> myofibril -> myofilaments -> myosin(thick), actin(thin)
myofibrils
contractile units + SR containing calcium
- contractile units = myofilaments
regulatory filaments
troponin, tropomyosin
(Troponin is attached to tropomyosin and lies within the groove between actin filaments in muscle tissue. In a relaxed muscle, tropomyosin blocks the attachment site for the myosin crossbridge, preventing contraction)
red muscle
high myoglobin content
many mitochondria
aerobic glycolysis
white muscle
creatine-phosphate as energy source (anaerobe), lactate is produced
energy source of fast(white) vs. slow(red) mm. contractio
fast: anaerobic glycolysis, creatine - P
slow: aerobic glycolysis, aerobic FA ox
fat is found where
subcutaneus
around organs: mechanical protection, heat insulation, energy production -> B-oxidation
how much energy fat burning vs. sugar burning
39kJ/g fat
17kJ/g glucose
pathways found in fat
lipolysis, B-ox, B-red, fat synthesis, FA synthesis, ketolysis, (glycolysis + TCA is less frequent - GLUT-4)
no. of fat cells
hyperplasia: more fat cells, younger age
hypertrophia: cells full of fat/FA -> bigger cells
brown adipose tissue
(thermogenin) uncouplers imp. for thermoregulation -> heat prod.
- no ATP prod as H⁺ is used for heat prod.
brain: mass and use of oxygen and glucose
2% body mass
20% of oxygen use
60% of glucose is used in the brain
blood brain barrier
endothelial cells of the caps - GLUT-1 is used
- large molecules cannot pass
- NH3 can pass and inhibit TCA with AKG
glucose dependance
no glycogen storage -> huge glucose need!
GLUT 1 and 3 is used in the brain, for uptake of what; energy use
- ketone bodies, some essential aa’s (both for energy!) some electrolytes
- no protein or FA can be taken up, except short chained unsaturated FA used for phospholipid, sphingolipid synthesis
