Physiology Flashcards
What is the role of dendrites?
recieve information from other neurones and convey graded electrical signals to the soma
What is the role of the soma/cell body?
integrates incoming signals that are conducted passively to the axon hillock
What is the role of the axon?
conducts output signals as APs to the presynaptic terminal
What are the 4 different types of neurons?
unipolar
multipolar
bipolar
pseudounipolar
Describe unipolar neurons?
one neurite - normally peripheral autonomic neurones
Describe pseudounipolar neurons?
one neurite that bifurcates - i.e. dorsal route ganglion
Describe bipolar neurons?
two neurites - pass info from one group to an other
i.e. rentinal bipolar neuron
Describe multipolar neurons?
three or more neurites
i.e. lower motor neuron
What is a projection neuron?
goes from the dorsal horn of the spinal cord to the brain structures eg cortex
What is a local interneuron?
between neurons in the CNS
What type of membrane resistance and axial resistance of the axoplasm do you want for a high AP length?
high membrane resistance (high myelination)
low axial resistance of the axoplasm (i.e. large diameter)
What produces myelin in the PNS?
Schwann cells
What produces myelin in the CNS?
oligodendrocytes
What is the most frequent excitory transmitter in the CNS?
glutamate
What does glutamate generate in the CNS?
excitory postsynaptic potential
What is the most frequent inhibitory transmitter in the CNS?
GABA
What does GABA generate in the CNS?
inhibitory postsynaptic potential
What does glutamate cause an influx of? and is it hyperpolarising or depolarising?
sodium
depolarising
What does GABA cause an influx of? and is it hyperpolarising or depolarising?
chlorine
hyperpolarising
Describe the action of an inotropic receptor?
direct gating - so receptor itself is a gated channel
rapid process
Describe the action of an metabotropic receptor?
indirect gating - recepor signals to a channel to make it open
slow process
Give an example of an inotrophic receptor?
ACh receptor
Give an example of a metabotrophic receptor?
G protein coupled receptors
What is the order of dominance of the spinal tracts?
corticospinal > rubrospinal > reticulospinal
What does the progression of decorticate positioning to decerebrate positioning indicate?
uncal or tonsillar brain herniation
What does decorticate positioning come from?
lesions above the red nucleus - so no coricospinal tract influence - only rubrospinal
What does decerebrate positioning come from?
lesions below the red nucleus - cuts out rubrospinal tract and leads to only reticulospinal action
