Muscle Pt 4

Question 1

Timing of EC coupling refers to . . . ?

Answer 1

1. Delayed start times in AP’s between motor nuerons & muscle fibers
2. Delay between muscle fiber AP & contanction time (latent period)

2. Ca+ is being released and binds to troponin

Question 2

T/F Muscles need a steady supply of ATP to function

Answer 2

True = or else u get rigos mortis

Question 3

What 3 main functions is ATP needed for?

Answer 3

1. Myosin ATPase (contraction)
2. Ca+ ATPase: SERCA (relaxation)
3. Na+/K+ ATPase (after AP in muscle fiber)

Question 4

List 2 sources for ATP

Answer 4

1. Free/natural intracellular ATP (not in huge supply however)
2. ATP fromed from phosphocreatine (donates ATP when needed)
3. Glucose stored as glycogen –> glycogenolysis = gives the MOST ATP

Question 5

What is the most abundant source of ATP?

Answer 5

Glucose, which we store and glycogen = which undergoes glyvogenolysis to give ATP

Question 6

Glycogenolysis is termed __ metabolism, due to occuring in absence of oxygen

Answer 6

anaerobic metabolism due to oxygen absence

occures in sarcoplasm of muscle.
Anarobic metabolism = gives off little ATP

Question 7

If oxygen & mitochondria are present than, then its termed oxidative (__) metabolism, which produces A LOT of additional ATP

axidative (aerobic) metabolism = makes 30-32 ATP

Question 7

If oxygen & mitochondria are present than, then its termed oxidative (__) metabolism, which produces A LOT of additional ATP

Answer 7

axidative (aerobic) metabolism = makes 30-32 ATP

Question 8

Muscle Fatigue refers to . . .

Answer 8

decrease in muscle tention as a result of preveous contractile activity (reversible with rest)

Question 9

What are 2 types of fatigue?

Answer 9

1. Central fatigue (physciological cell fatigue)
2. Peripheral fatigue (physiological & chemical fatigue)

1. (feeling of tiredness and desire to cease activity) You feel to tired to do anything, but you mechanically can
2. (some muscle fibres arn’t contracted due to AP) You feel tired and you mechanicaly / chemicaly can’t activate = less likely

Question 10

Propose 2 therioes explainf pheripheral fatigue

Answer 10

1. Failed EC coupling @ T-tuble (increase in extracellular K+)
2. Accumulation of phospahte, acid, ADP
   - Decrease Ca+ release/reuptake rate by SR
   - Decrease activation of thin filaments (TnC) by Ca+
   - direct inhibition of the binding & power stroke motion of the myosin cross-bridges

Question 11

What are 2 ways we classify skeletal muscle

Answer 11

1. Max velocity of shortening (fast/slow)
2. Main pathway used to make ATP (oxidative/glycotlytic)

Question 12

Max velocity of shortening can be further classified into . . .

Answer 12

1. Slowt fibers = myosin with slow ATPase activity
2. Fast fibers = myosin with fast ATPase activity

Question 13

Mian pathway used to produce ATP by skeletal msucle can be firther classified into . . .

Answer 13

1. Oxidative fibers = many mitocondria = aerobic metabolism = need oxygen
2. Glycolitic fibers = few mitochondria + many glycogen = glycolytic enzymes = don’t need ocygen

Question 13

Mian pathway used to produce ATP by skeletal msucle can be firther classified into . . .

Answer 13

1. Oxidative fibers = many mitocondria = aerobic metabolism = need oxygen
2. Glycolitic fibers = few mitochondria + many glycogen = glycolytic enzymes = don’t need ocygen

Question 14

List 3 types of skeletal muscle fibers

Answer 14

1. Type 1= slow-oxidative (rely on oxygen & slow ATPase) = dark red
2. Type 2A= Fast oxidative-glycolytic (allows both arobic & glycolytic metabolsim & fast ATPase) = pink
3. Type 2X = fast glycolytic (rely on glycolysis and fast ATPase) =white/beige