Nervous system

Question 1

What are the three classifications of neurons?

Answer 1

Afferent: sensory, visceral
Efferent: Autonomic, somatic, parasympathetic, sympathetic
Interneuron

Question 2

Describe the structure of axon?
Axon hillock
soma
Dendrite
axon

Answer 2

Axon hillock: Where initiation spike happens
Soma: cell body
Dendrite: extension of cell body
Axon: to effector

Question 3

At rest, what is the inside of the neuron like?

Answer 3

RMP (resting membrane potential)= The inside is more negative compared to the outside.
3 sodium leaks out, 2 K+ leaks in.
All voltage gated channels are closed.

Question 4

What are the three different types of gates?

Answer 4

Non gated channels (Leak channels): sets RMP
Voltage gated: generates action potentials
Ligand (Chemical): potential changes at synapses.

Question 5

Describe action potentials etc?

Answer 5

1. At rest: 3 na out, 2 k in.
2. Depolarisation: Na+ conduction gates open and membrane is depolarised. Na+ floods in.
3. Due to the change in voltage, all Na+ voltage gated channels open.
4. Na+ channels close after action potential, K+ opens.
5. Most gates are closed, K+ still open, this causes hyperpolarisation.
6. K+ voltage gated channels close and so leak channels rest the RMP.

Question 6

How are the CNS protected?

Answer 6

Cranium
Meninges
Cerebrospinal fluid
Blood-brain barrier

Question 7

What do the meninges do?

Answer 7

Wrap, protect and nourish the CNS
There are 3 membranes: Dura mater, Arachnoid mater (Highly vascularised), Pia mater.

Question 8

What does cerebropsinal fluid do?

Answer 8

Produced by choroid plexus.
Shock absorbing
Exchange of materials between neural cells