Muscle Phys II Flashcards
How does the phosphagen system work and how much energy does it provide
Uses creatine phosphate to regenerate atp quick (direct phosphorylation (provides energy for the first 8-10 sec)
Anaerobic glycolosis- what is created and how long does it provide energy for
Pyruvate converted to lactic acid due to lack of O2
-Provides energy for about 30-60 sec of exertion
Oxidative phosphoylation- how much atp does it produce
95% of atp during rest and light-mod activity
ETC- how much atp does it produce and what is required for it to work
90% of the ATP used by the body for functions
Requires vit B2, iron, copper
What is oxygen debt used for (3)
- replenishing o2 resevers
- Help get rid of lactic acid
- Used in ox phosphorylation to produce atp (by converting creatine to creatine phosphate, amp to atp)
Type 1/slow oxidative- myoglobin content, capillary count, mito count, glycogen stores
myoglobin content, high
capillary count, high
mito count, high
glycogen stores, low
Type IIa/ Fast oxidative- myoglobin content, capillary count, mito count, glycogen stores
myoglobin content, high
capillary count, high
mito count, high
glycogen stores, medium
Type IIb/ Fast glycolitic- myoglobin content, capillary count, mito count, glycogen stores
myoglobin content, Low
capillary count, Low
mito count, Low
glycogen stores, High
What is the avg mm distribution of mm fibres
55-65% type 1
30-35 type IIa
15% type IIb
What are some mm adaptations to endurance training
more myoglobin, mito
angiogenesis
smaller mm fibres (smaller distance for o2 and glucose to diffuse
What are some mm adaptations to power training
hypertrophy of type II
increase in muscle length + # of sarcomeres
What mm fibres can change in more endurace training
fast cant change to slow but.
can result in a shift of type IIb to IIa
What are the 3 types of motor units
S- slow
FR- fast, resistent to fatigue
FF- fast, fatiguable
what types of mm have small and large motor units
mm that control fine movements have small mm units (for better control, low threshold)
mm that control large mvmts have large mm units (higher threshold)
How does recruitment of mm units occur
smaller fibres will be recruited first and as the strength of the signal increases the progressivel larger fibres will be recruited
what does a simple twitch result in
Result of a single stim of a mm, leading to contraction of all fibres in a motor unit (response to a single threshold stim)
what is a incomplete tetnus due to
the result of multiple stim leading to a repeated wave of summations
What is fused/complete tetnus (how much stronger is it than a simple twitch)
a sustained and smooth max contraction in which multiple stim occur close in time
(3-4x stronger than a simple twitch)
What is the Frank Starling Law
Strength of mm contraction that is directly proprotionate t the initial length of the mm
What is L-max
the optimal sarcomere length where max number of cross bridges are formed
Why does muscular fatigue occur (5)
- Depletion of energy stores
- Lack of o2 leading to atp deficit
- Accumulation of lactic acid (inhibits enzymes)
- Accumulation of K in the ECF (disturbed excitability)
- ROS (decreased Ca sensitivity)
Why does neuromuscular fatigue occur + why
due to increased release of Ach at NMJ
-this type of fatigue occurs during fast/powerful activities
Why does central fatigue occur + why (2)
When the CNS no longer adequetly activates the motor neurons supplying mm
-Hypoglycemia + acidosis (from lactic build up)