Physiology

Question 1

What is the role of dendrites?

Answer 1

recieve information from other neurones and convey graded electrical signals to the soma

Question 2

What is the role of the soma/cell body?

Answer 2

integrates incoming signals that are conducted passively to the axon hillock

Question 3

What is the role of the axon?

Answer 3

conducts output signals as APs to the presynaptic terminal

Question 4

What are the 4 different types of neurons?

Answer 4

unipolar
multipolar
bipolar
pseudounipolar

Question 5

Describe unipolar neurons?

Answer 5

one neurite - normally peripheral autonomic neurones

Question 6

Describe pseudounipolar neurons?

Answer 6

one neurite that bifurcates - i.e. dorsal route ganglion

Question 7

Describe bipolar neurons?

Answer 7

two neurites - pass info from one group to an other

i.e. rentinal bipolar neuron

Question 8

Describe multipolar neurons?

Answer 8

three or more neurites

i.e. lower motor neuron

Question 9

What is a projection neuron?

Answer 9

goes from the dorsal horn of the spinal cord to the brain structures eg cortex

Question 10

What is a local interneuron?

Answer 10

between neurons in the CNS

Question 11

What type of membrane resistance and axial resistance of the axoplasm do you want for a high AP length?

Answer 11

high membrane resistance (high myelination)

low axial resistance of the axoplasm (i.e. large diameter)

Question 12

What produces myelin in the PNS?

Answer 12

Schwann cells

Question 13

What produces myelin in the CNS?

Answer 13

oligodendrocytes

Question 14

What is the most frequent excitory transmitter in the CNS?

Answer 14

glutamate

Question 15

What does glutamate generate in the CNS?

Answer 15

excitory postsynaptic potential

Question 16

What is the most frequent inhibitory transmitter in the CNS?

Answer 16

GABA

Question 17

What does GABA generate in the CNS?

Answer 17

inhibitory postsynaptic potential

Question 18

What does glutamate cause an influx of? and is it hyperpolarising or depolarising?

Answer 18

sodium

depolarising

Question 19

What does GABA cause an influx of? and is it hyperpolarising or depolarising?

Answer 19

chlorine

hyperpolarising

Question 20

Describe the action of an inotropic receptor?

Answer 20

direct gating - so receptor itself is a gated channel

rapid process

Question 21

Describe the action of an metabotropic receptor?

Answer 21

indirect gating - recepor signals to a channel to make it open
slow process

Question 22

Give an example of an inotrophic receptor?

Answer 22

ACh receptor

Question 23

Give an example of a metabotrophic receptor?

Answer 23

G protein coupled receptors

Question 24

What is the order of dominance of the spinal tracts?

Answer 24

corticospinal > rubrospinal > reticulospinal

Question 25

What does the progression of decorticate positioning to decerebrate positioning indicate?

Answer 25

uncal or tonsillar brain herniation

Question 26

What does decorticate positioning come from?

Answer 26

lesions above the red nucleus - so no coricospinal tract influence - only rubrospinal

Question 27

What does decerebrate positioning come from?

Answer 27

lesions below the red nucleus - cuts out rubrospinal tract and leads to only reticulospinal action