Synapse & Neuromuscular Junction Flashcards
How do cells communicate electrically?
Gap junctions allow movement of ions
How do cells communicate chemically?
Synapses, hormones, cytokines, etc
How many synapses can there be on a single neuron?
~10,000
What is an axo-dendritic synapse?
Axon of a neuron connects with the dendrite of another
What is an axo-somatic synapse?
Axon of a neuron connects with a cell body
What is an axo-axonic synapse?
Axon of one neuron connects with the axon of another
Why are action potentials in muscle cells broader?
Ca2+ entering for contraction as well as depolarisation (excitation-contraction coupling)
What is the range of current measured during sub-threshold muscle stimulation?
10nA
What is the range of voltage measured during sub-threshold muscle stimulation?
10mV
How long does a single muscle depolarisation (sub-threshold) last for?
2ms
What can inhibit the reuptake of serotonin?
Selective Serotonin Reuptake Inhibitors/SSRI
How long does a muscle action potential last?
10ms
What enzyme degrades ACh?
Acetylcholine-esterase
What does the term “high safety factor” mean?
More neurotransmitter released than required to reach threshold to ensure an action potential is triggered
What are miniature end plate potentials?
Depolarisations smaller than end plate potentials that occur due to the release of a single presynaptic vesicle
(Random sub-threshold events)
What is an end plate potential?
Depolarisation of muscle fibre
Can be sub or supra-threshold
What ion coordinates miniature end plate potentials?
Ca2+
Results in excitatory post-synaptic potentials
What do IPSPs do?
Inhibitory post-synaptic potentials inhibit some action potentials
If the membrane becomes permeable to an ion what will happen?
Ion will move down its electrochemical gradient
Driving the Vm towards its own equilibrium potential
How should you alter the charge of the cell to stop Na+ entering?
Make it more positive (repulsion)
How should you alter the charge of the cell to stop K+ leaving?
Make it more negative (attract K+ back)
What gives rise to the membrane potential?
Separation of ions
