MSK- physiology Flashcards
Dark bands
Myosin
Light bands
Actin
Skeletal muscle features
Motor units, striated, voluntary control, neuromuscular junctions, no gap junctions
Purpose of skeletal muscle
Movement, posture, heat production, metabolism, respiratory movement
Motor unit
A single alpha motor neuron and all the skeletal muscle fibres it innervates
Power>precision
More fibres per motor unit
Myosin
Darker
Actin
Lighter
Sarcomeres
Functional unit of the muscle
Muscle tension sliding filaments theory
Sliding of actin filaments on my pin filaments
Calcium is released from where in skeletal muscle fibres when surface action potential spreads down what?
Lateral sacs of sarcoplasmic reticulum, t-tubules
Factors determining graduation of muscle tension
-No of muscle fibres contracting within muscle
-tension developed by each contracting muscle fibre
Tension developed by each contracting muscle fibre depends on
-frequency of stimulation and summation
- length of muscle fibre at onset of contraction
-thickness of muscle fibre
What happens when skeletal muscle is stimulated once
Twitch produced
What happens when muscle fibres are stimulated so rapidly there is no opportunity to relax at all between stimuli
Tetanus occurs
Optimum length of skeletal muscle is approximately the length of what
It’s resting length
Isotonic contraction
Muscle tension remains constant as muscle length changes (body movements and maintaining objects)
Isometric contraction
Muscle tension develops at constant muscle length (body posture etc)
Oxidative phosphorylation
Main source that supplies ATP when oxygen is present
Glycolysis
Main source that supplies ATP when oxygen is not present