Membrane Potentials and Nerves Flashcards
What is the membrane Chanel status in the absolute refractory period?
Nearly all Na+ channels are inactive
How can action potentials be generated in the relative refractory period?
Na+ channels are recovering from inactivation so the membrane is excitable again if the stimulus is great enough.
If you increase the selective permeability to a certain ion of a membrane what happens?
The membrane potential moves toward that of the ion
Describe ion movement in action potential generation.
Sodium channels open and it influxes depolarising the membrane.
The influx of sodium through open channels makes them prone to deactivation.
The depolarised membrane opens potassium channels so it effluxes until they slowly close.
What are the 5 devising of the spine?
Mint Chocolate Taste Like Soap- a pneumonic to help
Medullary Cranial Thoracic Lumber Sacral
Which ion influxes into cells to generate an action potential?
Na+
How do sodium channels stop transporting sodium in an action potential?
Open sodium channels are prone to deactivation
What ion drives hyperpolarisation?
K+ slowly effluxes after the influx of sodium opens more K+ channels. The closing of these channels takes time and so the membrane potential tends to over shoot the resting potential
Adrenaline and noradrenaline are neurotransmitters at which junctions?
Sympathetic neuromuscular
Acetyl choline has two receptor types. Name them and list the locations in which they are found.
Nicotinic AChR are found at junctions between pre and post ganglion if nerve fibres in the entire autonomic nervous system (sympathetic and parasympathetic).
It is also seen as the neurotransmitter and the effector site for somatic nerves.
Muscarinic are found at the parasympathetic neuromuscular junctions.
Which is the fast and which is the slow acetyl choline receptor and why?
Nicotinic are fast because they have intrinsic ion channels.
Muscarinic are slow because they are a G protein coupled receptor.
Why is the resting potential closer to the equilibrium potential for K+ than Na+?
The membrane has higher permeability for potassium than sodium
List the 4 types and the locations of the parasympathetic receptors we have learnt about?
M1 - glands
M2- heart
M3- lungs, GI and glands
Nitrous Oxide- penis (secondary to acetyl choline) and the iris sphincter,
Sympathetic receptors include alpha 1 , beta 1 and beta 2, where are they found?
B1 heart
A1 eye
A1 B2 facultative
B2 lungs uterus and intestine
What does the sympathetic nervous system encourage the release of from the kidney?
Renin
