Lecture 2

Question 1

Strcuture and function of denditres and cell body (neuron)

Answer 1

Dendrites: Branch-like structures that receive information from other neurons.
Cell body: Holds the memory of the functions of the neuron. Responsible for the creation of transmitter molecules (selectively released).

Question 2

Structure and function of axon and myelin sheath

Answer 2

Axon: Long extension from cells body and through it electrical impulse pass
Myelin sheath: Tight group of glial and schwaan cells that insulate the nerve cell.

Question 3

Function of the nodes of ranvier | terminal buttons and synapse

Answer 3

Nodes of Ranvier: Also aid in speed up neural impulses, though they are not myelinated on axon.
Terminal Buttons: Involved in releasing neurotransmitters into the synapse.

Question 4

How is a message transmitted from neuron to neuron/s?

Answer 4

cell sends electrical charge through axon towards pre-synaptic terminal and stimulates it. This will trigger the release of neurotransmitters from the presynaptic terminal, past the synaptic cleft in to the post synaptic terminal.

Question 5

What is polarisation of a neuron?

Answer 5

Refers to the resting potential of neuron - i.e not firing.
- Na+ and Cl- found outside cell membrane whereas k+ is found inside. Slightly permeable to k+ ions so a polarised neuron = -70millivolts relative to the outside. Some Na+ able to cross membrane at rest but the ratio is kept that -70 millivolts.

Question 6

What type of ions contribute to polarisation and depolarisation?

Answer 6

Positively charged ions make the receiving neuron less polarised.
If positively charged ions flow out of neuron or negatively charged ions flow in = polarisation.

Question 7

What are excitatory post synaptic potentials?

Answer 7

A depolarising post synaptic potential (fires action potential) - EPSP

Question 8

What are inhibitory postsynaptic potentials?

Answer 8

When positively charged ions flow out of neuron or negatively charged ions flow in = hyperpolarisation = IPSP

Question 9

What is an action potential?

Answer 9

Electrical current as a result of the depolarisation of neuron. Neuron will then open na+ and k+ gates to push positively charged ions out to polarise (70 millivolts)

Question 10

How is involved in the process of axonal conduction?

Answer 10

Speed in action potential can vary from 0.2 metres p/sec to 120 metres p/sec, depends on myelination and nodes of ranvier (salutatory conduction). Action potential propagates and jumps from one node to next

Question 11

How does a neuron generate signals

Answer 11

Through the release of neurotransmitters stimulated semipermeable receptors on post synaptic neuron.

Question 12

Acetylcholine (function and malfunction)

Answer 12

function: memory, movement
malfunction: alzheimer’s disease

Question 13

Norepinephrine (function and malfunction)

Answer 13

function, mood, sleep, learning

malfunction: depression

Question 14

Serotonin

Answer 14

function: mood, appetite, impulsivity
malfunction: depression

Question 15

Dopamine

Answer 15

function: movement, reward
malfunction: Parkinson’s disease, schizophrenia

Question 16

GABA

Answer 16

function: sleep, movement
malfunction: anxiety, huntington’s disease, epilepsy

Question 17

Glutamate

Answer 17

function: memory
malfunction: Damage after cardiovascular event

Question 18

Distinguish between an agonist and antagonist

Answer 18

Agonist: That which facilitates the effects of a particular neurotransmitter (receptor
Antagonist: That which blocks inhibits the effects of a particular neurotransmitter (receptor blocker)

Question 19

Example of agonist drug and it’s effects

Answer 19

Cocaine: potent catecholamine agonist. Increases the activity of both dopamine and norepinephrine by blocking their reuptake.