Cellular Neurophysiology

Question 1

Action Potential (AP)

Answer 1

an electrical impulse that changes the permeability of a membrane

Question 2

Transport proteins

Answer 2

(channels/carrier) facilitates ion movement across the plasma membrane

Question 3

Chemical gradient (concentration gradient)

Answer 3

the energy provided by the difference in concentration across the plasma membrane

Question 4

Electrochemical gradient

Answer 4

the energy associated with moving charged molecules across a plasma membrane - when a membrane potential exist

Question 5

Nerst potential value

Answer 5

this tells us what the membrane potential is if one ion is in control

Question 6

Resting Membrane Potential (RMP)

Answer 6

charge difference across the plasma membrane

Question 7

Na+ / K+ ATPase

Answer 7

maintains the RMP by ensuring that K+ and Na+ does not reach equilibrium

Question 8

Local potentials

Answer 8

changes in membrane potential of a cell neuron occurring at and nearby the part of the cell that is stimulated

Question 9

axial resistance

Answer 9

How well a current can move through the cytoplasm

• bigger axon diameter, less axial resistance

Question 10

Depolarisation

Answer 10

The change from a negative resting potential to a positive resting potential which is caused by the opening of sodium channels

• moves towards zero, more positive

Question 11

Overshoot

Answer 11

anything that cause the membrane potential to pass across zero

Question 12

repolarisation

Answer 12

the change from a positive resting potential back to a negative resting potential which is caused by the opening of potassium channels

• move away zero, become mor negative

Question 13

Hyperpolarisation

Answer 13

An increase in the potential difference across a cell membrane, making it more negative than the resting membrane potential (>-70)

Question 14

polarisation

Answer 14

when the outside of the cell is zero and the inside of the cell is -70 its polarised

Question 15

threshold

Answer 15

Level of stimulation needed to trigger a neural impulse

Question 16

absolute refractory period

Answer 16

time during which another action potential is impossible; limits maximal firing rate

Question 17

relative refractory period

Answer 17

the period of time following an action potential, when it is possible, but difficult, for the neuron to fire a second action potential, due to the fact that the membrane is further from threshold potential (hyperpolarized)

Question 18

afterhyperpolarisation (undershoot phase)

Answer 18

the hyperpolarizing phase of a neurons action potential where the cells membrane potential falls below the normal resting potential

Question 19

regenerative

Answer 19

propagated without decreasing amplitude

Question 20

How is RMP altered if threshold is not reach?

Answer 20

it occurs by changing the permeability of the membrane to a particular ion

Question 21

conductance

Answer 21

the permeability and dricving force together

Question 22

Permeability

Answer 22

dictated by number of channels in the membrane and how many of them are open

Question 23

Activation gate

Answer 23

part of the voltage-gated Na+ channel that opens when the membrane voltage reaches threshold (value of depolarization)

Question 24

selectivity filter

Answer 24

the part of an ion channel structure that determines which ions it can transport

Question 25

inactivation gate

Answer 25

open at rest and closes relatively slowly after depolarization in a single step

Question 26

electrical signaling

Answer 26

action potential

Question 27

axon hillock

Answer 27

the only are where action potential is generated which is caused by the very high density of sodium voltage gated channels

Question 28

exocytosis

Answer 28

release of substances out a cell by the fusion of a vesicle with the membrane

Question 29

full fusion

Answer 29

vesicle collapses fully into the plasma membrane, retrieved through a clathrin-coated process

Question 30

Kiss and run fusion

Answer 30

when a vesicle forms a fusion pore but does not fully fuse with the cell membrane

Question 31

EPSP (excitatory postsynaptic potential)

Answer 31

a light depolarization of a postsynaptic cell, bringing the membrane potential of that cell closer to the threshold for an action potential

Question 32

IPSP (inhibitory postsynaptic potential)

Answer 32

synaptic potential that makes a postsynaptic neuron less likely to generate an action potential

Question 33

temporal summation

Answer 33

summation between EPSPs from the same input that occur close enough together in time

Question 34

Spatial summation

Answer 34

summation between events that occurs close enough together in space from different inputs - still requires them to be close in time

Question 35

endplate potential

Answer 35

the postsynaptic potential that occurs in the motor endplate in response to release of acetylcholine by the terminal button

Question 36

long term potentiation

Answer 36

an increase in a synapse's firing potential after brief, rapid stimulation. Believed to be a neural basis for learning and memory

Question 37

Neurotransmitters

Answer 37

chemical signals that initiate actions

Question 38

Glutamate

Answer 38

most prevalent excitatory neurotransmitters - glutamate release allows excitation of post synaptic membrane to occur

Question 39

GABA

Answer 39

most prevalent inhibitory neurotransmitter - GABA being release at the post synaptic cell will going to get inhibitory (IPSP)

Question 40

2 types of receptors

Answer 40

1) ionic receptors: ion channels opens which allows ion through 2) g protein

Question 41

acetyl cholinesterase

Answer 41

Acetyl cholinesterase turns acetylcholine into acetyl coA which is then reuptake into the vesicles and recycled

Question 42

synergy

Answer 42

an interaction between two different types of hormones which are combined together and this results in a greater effect than the sum of their separate effects

Question 43

hormone targeting

Answer 43

they bind with specific proteins receptors inside or in the surface of the cell and specifically change the cell's activities

Question 44

upregulation

Answer 44

how likely it is to bind hormones to its receptors is dependent on the balance between the synthesis and degration

Question 45

downregulation

Answer 45

degrade more of receptors than we synthesized, decrease number of receptors will decrease the sensitivity

Question 46

intracellular receptors

Answer 46

these are lipid soluble so they can cross across the membrane, but as they not water soluble they can not float freely in a solution. These are receptors that detects hormones.

Question 47

steroid hormone complex

Answer 47

activates primary responses in genes - inhibits transition and induces synthesis of gene

Question 48

Primary responses

Answer 48

turns on or shut off other responses and generate a whole lot of secondary gene transcription

Question 49

Ligand gated ion channel

Answer 49

an integral membrane protein that contains a pore which allows the regulated flow of selected ions across the plasma membrane

Question 50

ryanodine receptors

Answer 50

- a calcium channel - responsible for calcium release from the intracellular store during the excitation contraction coupling in both cardiac and skeletal muscle

Question 51

Kinase

Answer 51

- an enzyme which adds phosphates to other molecules - anything that contains a kinase will be able to phosphorylate proteins and turn on channels

Question 52

confirmational change

Answer 52

changing the charge in the amino acid will change the structure of the protein