Muscle Physiology Flashcards
Types of muscle tissue
Skeletal-striated, facilitates movement, voluntary
Cardiac- mono-nucleated, striated, involuntary
Smooth-non striated. Found in organ walls
Capillaries
Tiny blood vessels with very thin walls.
Allow for the dissuasion of oxygen into muscles and cells
Aid in removal of waste.
Myofibrils
Each cylindrically shaped muscle fiber within the muscle belly. Contain myofiliments: actin/ myosin.
Sarcoplasmic reticulum
T tubules
Tubular calcium storing network.
t Tubules: run from the sarcolemma
Motor Unit
Used to describe a given motor neuron and all the muscle fibers it innervates
Sliding filament theory
Action potential travels down the T-tubules and stimulates the SR>calcium is released from the SR, acting as a key to unlock the bond between the thin actin contractile filament and troponin>troponin molecule moves away from binding sites to allow myosin to attach to actin forming crossbridges> ATP is split at the actin/myosin attachment site and energy is release, allowing the muscle fiber to contract and produce force .
All or non principle
Muscle fiber is either in a state of producing maximum tension or not producing any tension at all.
Synchronized firing:
Employed during high output demands involving fast twitch fibers and warranting significant total fiber recruitment.
Asynchronous firing:
Employed during endurance exercises involving slow twitch fibers to allow for prolonged work.
Force production
Dependent on adaptation that occur to:
Muscle fibers>increase in size
Nervous system> increase in total fiber recruitment, improved firing rates, improved firing synchronicity
Protective organelles
Muscle spindles-react to rapid stretching and limit over stretching and damage to muscle.
GTO-sensory receptors, if tension becomes too great they inhibit/ reduce motor neuron activity and thereby reduce the force of musculature contraction.
Fatigue
The inability to produce force despite continued neural stimulation.
CNS
PNS
Short term fatigue
Exhaustion of ATP/ CP reserves Reduction in muscle pH Insufficient oxygen supply Compromised enzyme activity Tubular system disturbances
Long term fatigue
Depletion of storage glycogen Blood glucose Damaging to SR Significant dehydration Depletion of electrolyte ions
Muscle cell recovery is dependent on…
Replenishment of intracellular energy supply
By-product removal
Delivery of O2
