Chapter 8 1c Excitation Flashcards
What are the four stages of muscle physiology?
excitation
excitation-contraction coupling
contraction
relaxation
What is the purpose of excitation in muscle contractions?
muscle is stimulated
What is the coupling (E-C) period of muscle contraction?
a short period between the signal and when the muscle starts contracting
What happens during the contraction phase of muscle contraction?
when the muscle shortens and contracts when the actin and myosin grab onto each other and pull
Is a cell more negatively charged inside or outside the cell?
inside
What is the resting membrane potential?
stored potential energy
what does it mean for a cell to be isotonic?
it has the same concentration inside and outside
what is a connection between two electrically excitable cells?
synapse
what is the synapse called that occurs where a nerve fiber connects with its target muscle?
neuromuscular junction (NMJ)
Name the pink highlighted region
synaptic knob
name the pink highlighted region
synaptic vessicle
what does the synaptic vessicle carry?
a neurotransmitter called Acetylcholine
what is the abbreviation for acetycholine?
ACh
what is another name for the synaptic knob?
terminal
what is ACh and what does it do?
neurotransmitter that stimulates muscle cells
what part of the muscle cell is highlighted in pink?
sarcolemma
what is the name for the region containing the sarcolemma where the muscle connects to the nerve?
motor end plate
what are the pink highlighted regions on the motor end plate called?
junctional folds
what is located along the junctional folds of the neuromuscular junction?
ACh receptors
what is the pink highlighted region between the motor neuron and the muscle cell?
synaptic cleft
What is the nerve impulse?
the quick flip in positive and negative charges
What is another name for the nerve impulse?
action potential
what is the process in the neuromuscular junction from nerve impulse to muscle action potential?
- action potential (nerve impulse) comes down the neuron
- calcium channels open due to the nerve voltage
- calcium goes down concentration gradient into the synaptic knob
- calcium triggers the synaptic vessicles to release ACh through exocytosis
- calcium enters synaptic cleft
- ACh binds to ACh receptors
- sodium comes in, which changes the charge from positive to negative, and that creates a muscle action potential
- muscle action potential spreads all throughout the muscle cell
are the calcium channels voltage-gated in a neuromuscular junction event?
yes
What is the resting membrane potential?
the negative potential energy inside of the cell before the nerve impulse hits
what happens to the cell charge when the sodium channels open and what is it called?
we go from negative to positive
depolarization
after the cell charge goes past zero and becomes positive, what happens?
sodium channels start to close and potassium channels open
what is it called when the potassium exits the cell after the sodium creates a positive charge?
repolarization
