Contraction Of A Muscle Flashcards
Ability to shorten when an adequate stimulus is shortened
Contractility
Ability of muscle cells to be stretched
Extensibility
Ability to recoil and resume resting length after stretching
Elasticity
Stimulates skeletal muscles to contract
Motor neuron
What is a motor unit
One motor neuron and all the skeletal muscle cells stimulated by that neuron
A long, thread like extension of the neuron
Axon
When does the axon branch into axon terminal
The axon reaches the muscle and it forms a junction with the Sacrolemma
Where the axon terminal meets the sarcolemma
Neuromuscular joint
What is the neurotransmitter chemical
Acetylcholine
What is the synaptic cleft
Between the nerve and muscle
What is the nerve and muscle area between them filled with
Interstitial fluid
Chemical released by nerve upon arrival of nerve impulse and the axon terminal
Neurotransmitter
First step
Action potential reaches the axon terminal of the motor neuron
Second step
Calcium channels open and calcium Ions enter the axon terminal
3rd step
Because the calcium ions enter it causes some synaptic vesicles to release their contents (acetylcholine) by exocytosis
4th step
Acetylcholine diffuses across the synaptic cleft and binds to receptors in the sarcolemma
Ability to receive and respond to a stimulus
excitability
6th step
ACh effects our ended by it’s breakdown in the synaptic cleft by the enzyme acetylcholinesterastase
The sliding filament Theory of muscle contraction
Activation by nerve causes myosin heads to attach to binding sites on the thin filament
myosin heads then bind to the next site of thin filaments and then pull them towards the center of the sarcomere
Different degrees of skeletal muscle shortening
Graded responses
What produces graded responses
The frequency of muscle stimulation and the number of muscle cells being stimulated
Single brief jerky contraction
Twitch
What is a summing of contractions
Contraction is immediately followed by another
Does a muscle go completely back to resting position in summing of contractions
Oh no do to more frequent stimulations
What is unfused tetanus
Some relaxation occurs between contractions
Which has nerve stimuli arrive at the faster rate unfused tetanus or something of contractions
Unfused tetanus
What is fuse tetanus
No evidence of relaxation before the following construction
Why is there no relaxation between contractions infused tetanus
The frequency of stipulations is so high
What determines muscle force
Number of fiber stimulated
When do muscles stop contracting
run out of energy
Initially muscles use what energy
Stored ATP
What happened to ATP to release energy
Bonds are broken
Much energy comes from stored in ATP
4-6 seconds
Phosphorylation
Add a creatine phosphate to ADP to regenerate ATP
I’m how long does it take CP supplies to be exhausted
15 seconds
What is aerobic respiration
Loukos is broken down to carbon dioxide water and releases energy
How much energy is released in aerobic respiration
32 ATP
What is anaerobic glycolysis
Reaction that breaks down glucose without oxygen
In anaerobic glycolysis glucose is broken down into what
Pyruvic acid and produces about two ATP
Pyruvic acid is transferred into
Lactic acid
What produces muscle fatigue
Lactic acid
What is a common cause for muscle fatigue
Oxygen debt
What is needed to get rid of lactic acid
Oxygen
Myofilaments are able to slide past each other during contractions
Able to shorten and move
Isotonic
Tension in the muscle increases and no movement
Isometric
Which type of exercise results and stronger more flexible muscles with greater resistance to fatigue
Aerobic exercise
Type of exercise increases muscle size and strength
Resistance exercise
5th step
channels to open that allows both sodium to enter the muscle and potassium to leave
Depolarization also occurs which is the electrical impulse that comes from more sodium entering then potassium leaving, which causes action potential
