Cellular Neurophysiology

Question 1

neurons

Answer 1

info processing nerve cells

Question 2

characteristics of neurons

Answer 2

elongated
separated by synapses
in a network
electrically active
lots of them

Question 3

function of glia

Answer 3

support neurons physically and chemically
regulates blood flow and supply of nutrients to neurons
guides development
guides neural migration and produces chemicals to stop it

Question 4

what do some glial cells contain

Answer 4

insulating myelin

Question 5

what does the cell body contain

Answer 5

the cell nucleus

Question 6

synonym for cell body

Answer 6

soma

Question 7

dendrites

Answer 7

short network of thin projections from neuron cell body
RECEIVES signals from other neurons

Question 8

axons

Answer 8

long projection from cell body
impulse travels down axon to axon terminals
SENDS signals to other neurons

Question 9

what are axons covered in

Answer 9

myelin sheath - a fatty substance that serves as insulation for nerve impulses travelling along the axon

Question 10

each myelin wrapper is a projection from…

Answer 10

a glial support cell

Question 11

myelination

Answer 11

speeds up nerve conduction
happens over development
has functional consequences if disrupted

Question 12

what makes up the white matter in the brain

Answer 12

axons
composed of axonal fibre tracts connecting different brain areas

Question 13

what makes up the grey matter in the brain

Answer 13

cell bodies and dendrites

Question 14

what creates the white colour of white matter in the brain

Answer 14

comes from fatty myelin sheaths around the axon

Question 15

how can fibre tracts in the brain be traced

Answer 15

chemical methods or diffusion MRI imaging

Question 16

at resting state what is the voltage of the cell

Answer 16

roughly -70mV
the cell is more negative on the inside than the outside because of different concentrations of negative and positive ions

Question 17

when does an actional potential occur

Answer 17

when the inside of the cell reaches threshold (-55mV roughly)

Question 18

what voltage is threshold for an action potential to occur

Answer 18

roughly -55mV

Question 19

what pump maintains resting potential of the cell membrane

Answer 19

sodium-potassium pump

Question 20

what is saltatory conduction

Answer 20

where the action potential jumps between the gaps in the myelin sheath known as nodes of ranvier

Question 21

how do glial cells communicate

Answer 21

chemically

Question 22

what is moved in and out due to the sodium potassium pump

Answer 22

3Na+ out for every 2K+ in

Question 23

what powers the sodium potassium pump

Answer 23

energy produced from ATP -> ADP + Pi + energy

Question 24

how is ADP formed for the sodium potassium pump to work

Answer 24

ATP -> ADP + Pi (inorganic phosphate) + energy
hydrolysis of ATP (adding a molecule of H20) creates ADP + an inorganic phosphate + energy
the energy is used to pump 3Na+ out and 2K+ in to the membrane

Question 25

ligand gated ion channels

Answer 25

neurotransmitter gated ion channels
activated by the binding of a specific molecule (ligand)
a ligand can be a neurotransmitter, hormone, drug, etc

Question 26

depolarisation

Answer 26

occurs when threshold is reached (-55mV)
sodium ion channels open and sodium ions enter the neuron
makes the voltage increase

Question 27

repolarisation

Answer 27

occurs when roughly +30mV is reached
sodium ion channels close and potassium ion channels open and potassium ions enter the neuron
causes the voltage to decrease as the membrane is more permeable to potassium ions so they diffuse out of the neuron down the concentration gradient

Question 28

hyperpolarisation and refractory period

Answer 28

potassium ion channels are delayed to close so the voltage goes below resting potential (below -70mV)
known as the refractory period as voltage goes below resting potential and then increases again to restore -70mV

Question 29

what causes a neuron to fire

Answer 29

stimulation of a neuron with electric current can cause it to fire

Question 30

more electricity = …

Answer 30

more electricity = more action potentials

Question 31

describe process of synaptic transmission of neurotransmitters

Answer 31

presynaptic neuron excited by action potential
vesicles containing neurotransmitters bind to presynaptic membrane to release neurotransmitters
neurotransmitters released into synapse and diffuse across it
neurotransmitters bind to post synaptic receptors
this works via lock and key mechanism
this changes the polarisation of the cell
chemical activity either causes AP in next neuron or not