How nerves work Flashcards
What are the 3 main sub-divisions of the nervous system?
Brain
Spinal Cord
Peripheral nerves
What does the soma of a nerve contain?
The nucleus
What are dendrites of nerves used for?
An important route for information from other neurones
What does the axon of a nerve do?
Takes the AP elsewhere
What are the neurones typical resting membrane potential?
Around -70mV
What does the axon hillock do?
Triggers the action potential
What do the afferent neurones carry?
Sensory information
What do oligodendrocytes form in the CNS?
Glia
What do neurones exist to send?
Electrical signals
What do action potentials transmit?
Signals over long distances
What decides when an AP should be fired?
Graded potentials
What does the resting membrane potential rely on?
The permeability of the membrane to K+ ions
If the RMP is reduced, what is the cell doing?
Depolarising
If more K channels were to open, what would happen to the cell?
It would hyperpolarise
Where are endplate potentials found?
The NMJ
Why can graded potentials only work very locally?
They are decremental
What is required for long distance transmission?
Action Potentials
To hyperpolarise a postsynaptic potential, what channels can be opened?
K or Cl
Give 2 examples of IPSPs
GABA and glycine
Ligand-gated ion channels can produce what?
Postsynaptic potentials
Voltage-gated ion channels can produce what?
Depolarisation of the membrane potential
Action potentials are only fired when?
When the threshold is reached
What are action potentials mediated by?
Voltage-gated channels
Where does myelin originate from?
Schwan cells
Oligodendrocytes
Myelination allows what?
Nerve impulses to move quicker
Name the most known de-myelinating disease
Multiple sclerosis
Where is the AP triggered to contract muscle?
Sarcolemma
What is primarily opened following an AP in the motor neurone?
Voltage-gated Ca2+ channels in presynaptic terminal
Where does ACh diffuse across in the NMJ?
The synaptic cleft
What does tetrodotoxin block in the NMJ?
Na+ channels
Action potential
What do anticholinesterases block in the NMJ?
ACh breakdown
What is ACh inactivated by?
Breakdown
The NMJ is always a what cell?
Motorneurone-muscle cell
What is the collective name for the parasympathetic and sympathetic nervous systems?
Autonomic nervous system
