2 anatomy and physiology of nervous system Flashcards
where in the neurone does input come from
through the dendrite
do the nodes of ranvier have high conc of sodium channels
yes
steps of neuronal function
- neurotransmitter acts on receptors in dendritic spines
- depolarisation
- action potential generation and propagation
- neurotransmitter release
what is the resting membrane potential
-70mV
is the cell membrane more permeable to sodium or potassium
potassium
what happens when increased amounts of K+ enter cell
(development of resting potential)
the membrane potential drops, electrical force causes K+ to leave and Na+ to enter
resting potential develops
what activates sodium channels
change in voltage
when is an action potential created
when charge drops from -70mV to -55mV
what happens as potassium flows out the cell
makes inside the cell more negative (repolarisation)
do channels have the same refractory period
no, it changes depending on their function
what do afferent neurones do
carry signals away from sensory receptors and to the CNS
what do efferent neurones do
carry signals from CNS to effectors (muscles and glands)
where is the sympathetic ganglia
close to the spinal cord
where is the parasympathetic ganglia
close or within target organs
what is the neurotransmitter for the ganglia
acetylcholine for the sympathetic and parasympathetic
acts on nicotinic receptors
how are nerve plexuses in GI tract linked to cns and activated
through afferent fibres
activated by stretch and chemical stimulation
what are the main cell types of the CNS
neurones, astrocytes, microglia, oligodendrocytes
what myelinates the neurones
CNS - oligodendrocytes
PNS - Schwann cells
where are neurotransmitters released from
axon terminals
what does post synaptic input stimulate in the gut
gut motility and secretory activity
what do sympathetic nerves cause in the gut
presynaptic inhibition of postsynaptic induced contraction
what is the pathway connecting the brain to the PNS etc
the spinal cord
where does the spine receive peripheral input from
the dorsal horn
where does the spinal cord receive efferent input from
the ventral horn
