Physiology

Question 1

Define depolarisation

Answer 1

When the membrane potential becomes less negative

Question 2

Define hyperpolarisation

Answer 2

Membrane potential becomes more negative

Question 3

Define repolarisation

Answer 3

Membrane potential returns to resting potential after being depolarised

Question 4

In an AP what causes depolarisation?

Answer 4

Na+ influx

Question 5

In an AP what causes repolarisation?

Answer 5

K+ efflux

Question 6

___ influx happens before ___ efflux

Answer 6

Na+

K+

Question 7

What are the different states of the Na+ channels?

Answer 7

Closed state (generation of a new AP can happen) 
Open state
Inactivated state (generation of a new AP can't happen)

Question 8

An AP can be conducted over long distances without decaying true/false

Answer 8

True

Question 9

What is a graded potential?

Answer 9

A small change in the membrane potential

Question 10

An graded potential can be conducted over long distances without decaying true/false

Answer 10

False

the passive signals diminish as they spread from their site of intitiation

Question 11

What is the length constant?

Answer 11

λ= length constant

The distance that the current can travel before it diminishes to 0

Question 12

What does the distance over which a current spreads depend on?

Answer 12

Membrane resistance

Axial resistance

Question 13

What is membrane resistance?

Answer 13

Ability of the membrane to prevent leakage of current (should be high, minimal leakage)

Question 14

What is axial resistance?

Answer 14

Impedance of current inside the axons (should be small, minimal impedance of flow of ions within the axons)

Question 15

How do you increase membrane resistence?

Answer 15

Myelin sheath

Question 16

How do you decrease axial resistance?

Answer 16

Increase axon diameter

Question 17

_____ conduction is a factor in the propagation of the AP

Answer 17

Passive
(The passive spread of depolarisation to the adjacent distal region of the membrane slightly depolarises the new region causing opening of voltage-gated Na+ channels)

Question 18

How do you increase passive current spread (and thus increase AP velocity)?

Answer 18

Decrease axial resistance

Increase membrane resistance

Question 19

What is the method of conduction in myelinated axon called?

Answer 19

Saltatory conduction

Question 20

In myelinated axons what are the gaps in the myelin sheath called?

Answer 20

Nodes of Ranvier

Question 21

___ influx induces release of neurotransmitter from the presynaptic neuron

Answer 21

Ca2+

Question 22

Presynaptic neurons have _____ zones around which vesicles cluster

Answer 22

Active

Question 23

Postsynaptic neurons contain ______ ______ containing neurotransmitter receptors

Answer 23

Postsynaptic densities

Question 24

What are the 3 classifications of synapse based on morphology?

Answer 24

Axodendritic
Axosomatic
Axoaxonic

Question 25

What are the 2 classifications of synapse based on functionality?

Answer 25

Excitatory | Inhibitory

Question 26

At an excitatory synapse what neurotransmitter is commonly present?

Answer 26

Glutamate

Question 27

At an inhibitory synapse which neurotransmitters are commonly present?

Answer 27

GABA | Glycine

Question 28

What response does a excitatory synpase cause?

Answer 28

Excitatory postsynaptic potential (EPSP)

Question 29

What response does a inhibtory synpase cause?

Answer 29

Inhibitory postsynaptic potential (IPSP)

Question 30

In an EPSP there is influx of ___ ions

Answer 30

Na+

Question 31

In an IPSP there is an influx of ___

Answer 31

Cl-

Question 32

An EPSP ____ the membrane

Answer 32

Depolarises

Question 33

An IPSP ____ the membrane

Answer 33

Repolarises

Question 34

An IPSP can generate and AP (true/false)

Answer 34

False | makes the membrane potential more negative, EPSP can cause an AP in threshold is met

Question 35

What 2 types of synaptic integration is there?

Answer 35

Spatial | Temporal

Question 36

What is the difference between spatial summation and temporal summation

Answer 36

Spatial: 2 or more separate inputs arrive almost simultaneously from different presynaptic neurons Temporal: 2 or more APs arrive in rapid succession along a single presynpatic neuron

Question 37

What is net excitation?

Answer 37

The inputs from presynaptic neurons are combined and postsynaptic neurons compute whether there is going to be a net excitation (more than the resting potential) or a net inhibition (less than the resting potential) Threshold may be reached and an AP fired

Question 38

What receptors are involved in direct gating?

Answer 38

Ionotropic receptors

Question 39

What receptors are involved in indirect gating?

Answer 39

Metabotropic receptors

Question 40

In indirect/direct the gating of the channel is slower

Answer 40

Indirect

Question 41

What are the 4 functional region of a neuron?

Answer 41

Input Integrative Conductile Output

Question 42

What is the site of initiation of the "all or nothing" AP?

Answer 42

Axon hillock