Muscle physiology Flashcards
two main types of muscle
striated muscle
smooth muscle
what type of muscle do skeletal and cardiac muscle belong to?
striated
what is an example of smooth muscle?
line circulatory vessels
what is skeletal muscle?
a type of striated muscle, controlled by the voluntary (somatic) nervous system
aids locomotion
what is cardiac muscle?
a type of striated, myogenic muscle, controlled by the autonomic nervous system (involuntary)
tendon
a large piece of connective tissue
myomere
blocks of muscle along side of body
role on titin
anchors myosin to the z line
how can muscle tension be increased?
muscle fibre stimulated again, before it completely relaxed = tetanus
motor unit
a group of muscle fibres that get all their signals from same single motor neuron
asynchronous recruitment
not all muscle fibres recruited at once, but AT RANDOM - can delay fatigue
how can muscle fatigue be delayed?
asynchronous recruitment
what is the ‘endurance’ muscle fibre?
type 1, dark fibre (=lots of myoglobin) - marathon runner dominant, slow oxidative
what is the ‘sprinter’ muscle fibre?
type 2b/2a, light fibre, fast glycolytic/fast oxidative
how is muscle force regulated?
electricl signals dictate muscle force
contractile response lags behind action potential
structural & biochemical features of skeletal muscle which aids O2 delivery
weaving muscle capillaries
increased pH because of CO2 released leads to offload of O2 as lower affinity of haemoglobin to O2
neurogenic contraction
signal comes from outside of muscle
smooth muscle contraction
made up of alpha actin
no overlap of thick or thin filaments
availability of myosin to actin is regulated by myosin light chain
upon excitation…
Ca2+ binds to calmodulin
Ca2+ and calmodulin complex activates myosin light chain kinase
myosin light chain kinase phosphorylates myosin light chain
NOW myosin head is free to bind to alpha actin
