muscle contraction quiz Flashcards
impulse comes down axon of neuron due to a stimulus received
1
When impulse reaches axonal terminals vesicles located there release a neurotransmitter called acetylcholine
2
ACh goes across the synaptic cleft and binds to ACh binding sites on the sarcolemma
3
Binding of ACh causes sodium channels to open so membrane is permeable to sodium ions
4
Sodium ions rush into the cell from the interstitial lfuid and causes a positive charge inside the cell causing an action potential
5
Action potential causes calcium ions to be released from the sarcoplasmic reticulum
6
Calcium binds to binding site on actin
7
Once calcium binds- myosin head binds to to actin too. Pulls actin towards center of sarcomere to cause a contraction
8
When action potential ends, calcium releases from actin, myosin heads release from actin, potassium gets pumped outside to bring electrical potential back to normal
9
later, sodium and potassium pump used to get sodium back outside and potassium back insside
10
Contraction - can start again
11
Irritability
Ability to receive and respond to stimuli
Contractility
Ability to shorten if stimulated
Motor unit
One neuron and all the skeletal muscle cells it stimulated
Neuromuscular junction
Where axon of a neuron and sarcolemma meet
