1.1 Cells of the NS

Question 1

What are the two cells found in the brain?

Answer 1

Neurons and Neuroglia

Question 2

What different structures do neurons have to other types of body cells?

Answer 2

• Axon
• Dendrite
• Synapse

Question 3

What is the axon in a neuron?

Answer 3

Output side of the cell.
That can travel distances ranging from distances ranging from microns to metres.
The axonal membrane ‘excitable.’

Question 4

What is the dendrite in a neuron?

Answer 4

Input side of the cell.
It is highly branched with a number of processes extended from it.
They receive most of the excitatory input.
They contain filaments and are dynamic.

Question 5

What is the synapse on a neuron?

Answer 5

Point of specialised contact between two neurons.

Question 6

What similarities do neurons have to regular cells?

Answer 6

• Nucleus
• Rough ER
• Smooth ER
• Golgi complex
• Mitochondria
• Lysosomes
• Cytoskeleton

Question 7

What is a nucleus?

Answer 7

Site at which a cells DNA is stored.

Question 8

What is a rough ER?

Answer 8

Synthesises proteins

Question 9

What is smooth ER?

Answer 9

Synthesises fat

Question 10

What is mitochondria?

Answer 10

Powerhouse of the cell

Question 11

What are lysosomes?

Answer 11

Waste disposal system

Question 12

What is cytoskeleton?

Answer 12

Maintains cells shape and provides ‘rails’ for transport

Question 13

What are the 3 ways that neurons can be classified?

Answer 13

1. According to the number of processes
2. According to the length of the axon
3. According to the shape of a cell

Question 14

How are neurons classified in terms of the numbers of processes they have?

Answer 14

Bipolar: 1 dendrite
Multipolar: 1+ dendrite

Question 15

How are neurons classified in terms of their length?

Answer 15

Golgi type 1: long axon and is large
Golgi type 2: short axon

Question 16

How are neurons classified in terms of their shape?

Answer 16

Ovoid (egg shape)
Fusiform (spindle like shape)
Triangular

Question 17

How can neuroglia be described?

Answer 17

Nerve glue

Question 18

What are the types of neuroglia found in the CNS?

Answer 18

1. Oligodendrocytes
2. Astrocytes
3. Microglia

Question 19

What is the type of neuroglia found in the PNS?

Answer 19

Schwann cells

Question 20

What do oligodendrocytes make?

Answer 20

-Form myelin

Question 21

What is myelin? What is are myelinated segments and unmyelinated segments known as?

Answer 21

• single sheet of membrane, wrapped tightly around axonal segment
• myelinated segments are known as internodes
• unmyelinated segments are known as nodes of ranvier

Question 22

What shape are astrocytes?

Answer 22

Star

Question 23

How much of the brain volume do astrocytes make up?

Answer 23

20-50%

Question 24

What connect astrocytes? What do they cover?

Answer 24

They are connected by gap junctions
They cover capillaries

Question 25

How do astrocytes 'fence' in neurons

Answer 25

- make a cuff around the nodes of ranvier - ensheathing synapses and dendrites - projecting processes to cell somas

Question 26

What are astrocytes function?

Answer 26

1. induce/maintain tight junctions in endothelial cells that form BBB 2. uptake of neurotransmitters 3. neurovascular coupling

Question 27

What are microglia?

Answer 27

Small rod shaped stomas which have numerous processes extended out symmetrically

Question 28

What are microglia's function?

Answer 28

They are representatives of the immune system in the brain, as the brain is 'immunologically privileged site.' This is because the BBB restricts access id immune cells from the blood.