EXAM Flashcards
What control is Skeletal Muscle under
voluntary control
structure of muscle fibre
parallel made of myofibrils, surrounded by CT
single muscle fibre= multinucleated + large mitochondria
structure of myofibrils
contractile + striated fibre
with thick (myosin) and thin (actin) filiments
Bands + zones lines of skeletal muscle
A band- thick and thin filments
I band- thin filments
H zone- proteins that hold thick filments
Z line -> Z line = sacromere
M line- middle
what is muscle growth
adding a sacomere to muscle fiber
cross-bridge def
extension from thick filment to thin filment (in A band)
What is a thick filment
- myosin : motor protein (ATP), which move along actin filments
What is a thin filment
- actin : tropomyosin and troponin
myosin interaction
dimer, joining is when the shaft wrap together
myosin head stick out: with actin binding site + myosin ATPase
actin
individual spherical actin that form a double helix
tropomyosin vs troponin
tropomyosin: thin + double helix acts a a regulatory mechaism by covering binding site from actin +mysin interactions
troponin: three polypeptide that connects to 1 tropomyosin, 1 actin and another Ca2+
twitch summation
muscle fiber is restimulated beofre complete relaxation so twitch 2 adds onto twitch 1
tentanic contration
muscle fibers are rapidly stimulated =multiple twitchs and no relaxation
cause tetanus- strongest single unit twitch can cause fatiguee
causes of muscle fatigue
- local accumulation of ADP + pi (interfere with cross-bridge)
- accumulation of K+ (less excitable muscles)
- accumulation of lactic acid (prevent glycolysis effecting excitation-contraction coupling)
- reduced gycogen stores (during excersize)
long distance run vs sprint (short distance)
long- more red muscle fibers (slow twitch fibers) have fast oxidative fibers w/ many mitochondria and myoglobin
sprint- more white muscle fibers (fast twitch) have fast glycolytic fibers
what is tone
degree of contraction of a single unit smooth muscle
