Neuromuscular Physiology Flashcards
Basic neuron anatomy (6)
Dendrites Soma Axon hillock Axon Axon Terminal Synaptic clefts (gaps)
What do dendrites do?
pick up signals from other neurons
what is the soma?
the cell body
where are action potentials generated?
at axon hillocks
What 2 types of transport make up axoplasmic transport
Anterograde
Retrograde
What protein does anterograde transport use and where does it go
Kinesin
towards axon tip
What protein does retrograde transport use and where does it go
Dynein
back to cell body
What is axoplasmic transport?
microtubules made of tubulin running along axon
Where are electrical synapses found?
in the Heart
What are electrical synapses and what do they do
Gap junctions - bidirectional
allow ions and small molecule to pass through
What are chemical synapses and how do they work
synaptic vesicles pass neurotransmitters across the cleft
How does exocytosis of synaptic vesicles happen
Ca+ influx activates snare proteins on the outside of vesicles and within cell membrane
the snare proteins combine with each other pulling the vesicle towards the membrane
What are the 2 types of snare proteins
V-snare (vesicle) - Synaptotagmin, Synaptobrevin
T-Snare (membrance) - Snap-25, Syntaxin
What happens when muscle AP is trigger
travels down T-tubles opening Ca2+ release channels in SR
- Ca2+ into sarcoplasm
What does Ca2+ do once in sarcoplasm
binds to troponin exposing myosin binding sites allowing myosin heads to bind and power stroke to commence
what happens to Ca2+ after the power stroke
it is actively pumped out of sarcoplasm to restore low resting levels
What are the 4 neurotransmitter groups
Cholinergic Neurons
Catecholaminergic
Serotonergic
Amino Acidergic Neurons
Where are cholinergic neurons found?
all motor neurons in spinal cord and brain stem
- use acetylcholine
How is acetylcholine synthesised
Acetyl-CoA + Choline (Choline Acetyltransferase) = Acetylcholine
What are catecholaminergic neurotransmitters
Dopamine, norepinephrine, epinephrine
all stem from tyrosine
What does the neurotransmitter serotonin do?
happiness, sleep, digestive regulation
it’s regulation is related to exercise & light exposure
How does low serotonin levels effect dopamine
dopamine will be over produced
What does glutamate do ?
related to memory, learning
found in brain
what does GABA do?
calming neurotransmitter
related to anti-anxiety medication
How does cocaine effect neurotransmitters
Blocks re-uptake transport meaning neurotransmitter remains in the synaptic cleft
What does botox do?
cleaves snare proteins preventing vesicles binding to membrane
How does a dynamometer work?
measures force/strength in newtons or newton meters
what does electromyography do?
measures electrical changes in the potential of a muscle
from surface or intramuscular electrodes
How can areas of the brain be stimulated
magnetic stimulation
legs have a smaller area but arms is bigger giving more fine motor control
How is electrical stimulation used
insert electrical stimulation device into nerves of interest to send signals
What is the MWAVE
a response to electrical stimulation
- a compound muscle action potential
what is a Motor evoked potential (MEP) and how is to different to an MWAVE
Magnetic or electrical stimulation elicited through motor cortex travel than direct to muscle/nerve
What 3 things can be measured with neurotransmission
Excitability (M-wave area/amplitude)
Contractility (twitch force, peak time)
Voluntary Activation (1- (sTw/pTw)) *100
