Tissues 6 - Nerve

Question 1

What are the cerebral hemispheres 4 functional regions?

Answer 1

Frontal, parietal, temporal and occipital lobes.

Question 2

What are the gyri and suici?

Answer 2

In the cerebral hemisphere, the gyri are ridges and the suici are valleys.

Question 3

What 3 components does the brain stem consist of?

Answer 3

The midbrain, pins and medulla (in descending order)

Question 4

What is the positioning of the cerebellum?

Answer 4

Hindbrain structure attached to the brain stem.

Question 5

What is the role of the cerebellum?

Answer 5

Motor coordination, balance and posture.

Question 6

Where does the spinal chord extend from?

Answer 6

The medulla

Question 7

What are the two basic functions of the spinal cord?

Answer 7

Conduit for neural transmission, co-ordinates some reflex actions.

Question 8

List the 4 main types of neurones.

Answer 8

Unipolar, psueudo-unipolar, bipolar, multipolar

Question 9

Describe the structure of unipolar neurones.

Answer 9

There is 1 axonal projection from the cell body.

Question 10

Describe the structure of the pseudo-unipolar neurones.

Answer 10

There is a single axonal projection that branches to divide into two sections.

Question 11

Describe the structure of the bipolar neurones

Answer 11

There are two projections from the cell body, an axon and a dendron

Question 12

Describe the structure of multipolar neurones

Answer 12

There are numerous projections from the cell body

Question 13

How else may the cell body be referred to?

Answer 13

Soma or peikaryon

Question 14

What is the structure of the cell body?

Answer 14

The cell body contains nucleus and ribosomes, as well as neurofilaments (structure and transport).

Question 15

What is the structure of the axon?

Answer 15

Origionates from the soma at the axon hillock, and may branch into colaterals. Often covered in myelin.

Question 16

Describe the structure of dendrites

Answer 16

Dendeites are highly branched cell bodies, which are not covered in myelin.

Question 17

What are astrocytes?

Answer 17

Astrocytes are star shaped cells, the most abundent type in the CNS, which can proliferate.

Question 18

What is the function of astrocytes?

Answer 18

Astrocytes are faculative macrophages (involved in immunity). They are structural cells, involved in cell repair and neurotransmitter release and reuptake.

Question 19

What are ogliodendrocytes?

Answer 19

Ogliodendrocytes are the cells that myelinate the cells of the CNS. They have numerous projections, so can myelinate many neurones at once.

Question 20

What are Schwann cells?

Answer 20

Cells that myelinate neurones in the PNS. One cell myelinates one axon.

Question 21

What are microglial cells?

Answer 21

Specialised cells that act as macrophages in the CNS.

Question 22

What are ependymal cells?

Answer 22

Epithelial cells that line fluid filled ventricles, which regulate the production and movement of cerebrospinal fluid.

Question 23

What are neuroglial cells?

Answer 23

Cells in the nervous system that are not neurones

Question 24

What is the distribution of ions in the resting cell¬ and what is the resulting membrane potential?

Answer 24

Inside vs Outside: Na+ < & K+ > & Ca2+ < & Cl-

Question 25

Describe briefly how an action potential is generated.

Answer 25

• VGSC open
• Na+ in (depolarisation) VGKC open
• K+ out (repolarisation)
• Na+K+ATPase restores ion gradients
• 3Na+ + ATP out (resting configuration)
• 2K+ enters (active configuration)
• Pump returns to resting configuration.

Question 26

Describe briefly saltatory conduction.

Answer 26

• Myelin prevents the action potential spreading as it has a high resitance and low capacitance.
• Action potential jumps between the nodes of ranvier

Question 27

Describe what happens to a neurone at the axon terminal.

Answer 27

Action potential opens Ca2+ channels. Calcium ions flood in, and this causes vesicle exocytosis.

Question 28

What happens to neurotransmitters in the synapse?

Answer 28

Neurotransmitters activate receptors, are recycled by transporter proteins, or are metabolised by enzymes in the synaptic cleft.