skeletal muscle metabolism Flashcards
Muscle metabolism.
production of ATP in muscle fibres.
Sarcoplasmic ATP only lasts a few seconds.
3 sources of ATP production within muscle
creatine phosphate
anaerobic glycolysis
aerobic respiration
Creatine phosphate
where is it unique to?
provides what kind of effort and how many seconds?
which preference is it when contraction begins?
unique to muscle fibres
contract maximally for 15 seconds / 100m sprint
1st preference
Anaerobic glycolysis
when occurs?
when happens to glucose to generate ATP?
oxygen required?
what kind of effort?
when muscle activity continues but supply of creatine depletes
glycolysis
no oxygen
maximally for 2 mins (200m)
aerobic respiration
oxygen?
what kind of effort?
how does it happen?
in presence of oxygen pyretic acid (formed by glycolysis) enters mitochondria to generate ATP, water and heat = aerobic respiration
90% of ATP provided is activity lasts more than 10 mins (marathon)
Can mitochondria use fatty acids and amino acids too?
yes
Muscle fatigue.
what does it mean?
list 5 factors that contribute
inability to contract after prolonged activity.
build up of lactic acid
insufficient oxygen or glycogen
decline of Ca2+ within sarcoplasm
deflation of creatine phosphate
central fatigue is feeling of tiredness and desire to stop (protective mechanism)
muscle fibre classification.
what 3 structural characteristics?
what 3 functional characteristics?
myoglobin, mitochondria and capillaries
contraction and relaxation speeds
resistance to fatigue
what 3 categories is muscle fibre classification?
slow oxidative
fast oxidative - glycolytic
fast glycolytic
slow oxidative / slow twitch
structure
how is it’s ATP generated?
resistance to fatigue?
red in colour (lots of mitochondria, myoglobin and blood vessels)
ATP generated via aerobic respiration. slow speed contraction. maintain posture and endurance activities
high resistance to fatigue
fast oxidative - glycolytic (fast twitch A)
structure
how ATP generated ?
resistance to fatigue
red - pink in colour (lots of mitochondria, myoglobin and blood vessels)
both aerobic respiration and anaerobic glycolysis
walking and sprinting
faster speed of contraction
intermediate resistance to fatigue
fast glycolytic (fast twitch B)
structure
how generated ATP?
fatigue resistance
white in colour
Anaerobic glycolysis
rapid, intense movements of short duration (weight lifting)
low resistance to fatigue
Motor unit
what is it?
how does it work?
axon of somatic motor neuron branches and forms NMJ with many different muscle fibres
consists of 1 somatic moron neuron + all skeletal muscle fibres it stimulates
all fibres contract in unison
strength of contraction depends on size of motor unit and number activated
muscle tone
definition
involuntary, weak contraction of a small number of motor units. alternately active and inactive
types of muscle actions
isometric
isotonic (concentric nd eccentric)
Oxygen debt definition
added oxygen, her and above the resting oxygen consumption that is taken into the bod after exercise
