week 4: neurophysiology

Question 1

neurons

Answer 1

basic functional units of the nervous system

Question 2

glial cells

Answer 2

nourish, protect and physically support neurons

Question 3

what are the glial cells critical for

Answer 3

brain development

Question 4

oligodendrocyte glial cell

Answer 4

covers the axons of neurons with myelin

Question 5

parts of the neuron

Answer 5

dendrites
soma (cell body)
axon
terminal buttons
myelin

Question 6

dendrites function

Answer 6

receives messages from other neurons

transmit the information they received to the soma

Question 7

the soma function

Answer 7

controls the cells metabolism and maintenance

collates/collects messages from other neurons

Question 8

the axons function

Answer 8

carries messages away from the soma towards other neurons

these messages are called action potentials

Question 9

terminal buttons function

Answer 9

secrete neurotransmitters which affect the activity of other cells with which the neuron communicates

Question 10

myelin function

Answer 10

insulates some axons to promote efficient transmissions of action potentials
aids in increasing speed of the axon potential along the axon

Question 11

cell membrane structure

Answer 11

lipid bilayer

embedded with protein molecules which form pores/channels that control movement of material in and out of the cell

Question 12

cell membranes role

Answer 12

separates the intracellular and extracellular fluid

molecules are exchanged via the protein channels

Question 13

are the protein channels of a cell open or closed at rest?

Answer 13

a cell at rest protein channels are closed

Question 14

resting membrane potential

Answer 14

-70mV

derives from the difference in chemical composition inside and outside the cell at rest

Question 15

chemicals that result a RMP

Answer 15

concentrations of potassium ions (K+) chloride ions (CI-) negatively charged protein ions and sodium ions (Na+)

Question 16

what is an action potential?

Answer 16

a brief reversal in the resting charge of the neuron

Question 17

what causes an action potential?

Answer 17

triggered by an exchange of ions across the neuron membrane

Question 18

when does an action potential happen?

Answer 18

when the neuron membrane is depolarised and once it reaches the depolarisation threshold (-55mV) the neuron will fire an action potential. if the neuron doesn’t reach -55mV the action potential wont fire

Question 19

what is depolarisation?

Answer 19

when the RMP moves towards 0mV

Question 20

how does sodium and potassium ions move during the action potential?

Answer 20

sodium channels open and the sodium enters the cell which reverses the membrane potential. Potassium channels then open potassium leaves the cell restoring the membrane potential. Ion transporters pump sodium and potassium ions back to their locations.

Question 21

where is sodium and potassium ion located?

Answer 21

potassium ions is located within the cell

sodium ions is located outside the cell

Question 22

how is the speed of propagation of the action potential determined?

Answer 22

diameter of axon

presence/absence of myelin sheath

Question 23

myelin sheath

Answer 23

electric insulator

current can only flow across the membrane at the myelin breaks (nodes of ranvier)

Question 24

synaptic transmission

Answer 24

when an action potential reaches the terminal buttons it causes the release of specialised chemicals (neurotransmitters) that travel across the synaptic cleft and are received by other neurons dendrites

Question 25

what is the space that separates neurons called?

Answer 25

synaptic cleft

Question 26

types of neurotransmitters?

Answer 26

dopamine
serotonin
endorphins

Question 27

what is reuptake?

Answer 27

when the whole neurotransmitter molecule is taken back into the axon terminal of the neuron that released it

Question 28

what is diffusion?

Answer 28

when the neurotransmitter drifts away out of the synaptic cleft where it can no longer act on a receptor

Question 29

what is deactivation/degradation?

Answer 29

a specific enzyme changes the structure of the neurotransmitter so it is not recognised by the receptor