W9 Physiology of Muscles Flashcards
(28 cards)
what are the steps to sliding filament model for muscle contraction
- myosin cross bridge attached to actin myofilament
- the myosin head bends and pulls along actin filament
- more ATP causes myosin head to detach
- myosin head will rebind and attach to actin after ATP splits into ADP + pi
what is the A band of sarcomere
myosin
what is the I band of sarcomere
actin
what is the H zone of sarcomere
area of contraction of both actin and myosin
what tension results in muscle stretch
passive tension
what does active tension represent
recycling of cross bridge
how to calculate total tension of sarcomere from tension graph
sum of active and passive tension
what happens during isotonic contraction
- muscles expand in length
- induces muscle movement
what happens during isometic contraction
- muscles dont extend in length
- no movement
How does the same muscle reach different levels of tension and velocity?
diff num of motor units
summation of action potentials
what can motor neurons control in regards to muscle fibres
1 motor for many muscle fibres but only 1 muscle fibre per 1 motor
what is a motor unit
motor neuron and muscle fibre
how are motor units innervated
innervated by a single neuron
what muscle has 100s of fibres
soleus
what is temporal summation
multiple signals from the same presynaptic neuron
what is spatial summation
signals from multiple presynaptic neurons at the same time
when is each summation used
spatial = distanced
temporal = close
what do darker fibres have more of
mitochondria and aerobic respiration
what does oxidative phosphorylation allow for
aerobic metabolism
is slow oxidative fibre darker or fast oxidative
slow
what enzyme depletes ATP from muscles
apyrase
what does the amount of active tension rely on
length of sarcomere
what is the physiological reasons for muscle fatigue
local increase of phosphate
leakages of Ca2+
depletion of glycogen
what are slow twitch (type 1) fibres for and do
endurance
long periods activity and low tensions
