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Flashcards in Histology Deck (49):
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2 types nerve cells

Neurons
Neuroglia (glial cells)

1

Role neurons

Process, transmit info
Electrically excitable

2

Role of glial cells

Nourish, support protect neurons

3

Definition of a nerve

A bundle of 1 or more neurons

4

Neurons consist of

Cell body
Dendrites
Axon
Myelin sheath
Terminal endings

5

Neurons possess electrical excitability what does this mean

The ability to make action potential

6

Nerve stimulus definition

Anything able to trigger generation of action potential in a neuron
Can be internal/external

7

Neurons: cell bodies are known collectively as

Grey matter of NS

8

Collections of cell bodies are referred to as

Nuclei/centres in the CNS

ganglia in the PNS

9

Axons determine nerve length, vary from

<1mm CNS to 1m sciatic nerve

10

Function axon

Carries nerve impulses to another neuron away from body

11

Axon covered by a membrane called

The axolemma

12

The ends of axons are called

Axon terminals

13

Axon bundles are called

Tracts in CNS

Nerves in PNS

14

What makes up white matter of NS

Axons and dendrites

15

What are dendrites

'Little trees'
Receiving end of neuron

16

What is myelin sheath

Multi layered lipid & protein covering around the axons

17

Myelin sheath formed by what in embryo

Neuroglia/ glial cells

18

Myelin atom continues through childhood and peaks in

Adolescence

19

Covered axons are termed

Myelinated

20

3 functions myelin sheath

Insulates axon (covers axolemma)
Regeneration of axons in peripheral NS
Increases speed of nerve impulse conduction (by forming gaps)

21

Neuroglia also known as

Glia
Glial cells

22

Can neuroglia multiply & divide

Yes
Unlike neurons

23

Situation of neuroglia

Surround and bind neurons

24

Size/no neuroglia compared to neurons

Far smaller
3-50 times as many

25

What will glia do after trauma

Fill spaces left by damaged neurons

* malignant growth of tumours

26

4 functions of Glia

Surround neurons and hold them in place
Supply nutrients/oxygen to neurons
Insulate one neuron from another
Destroy pathogens, remove dead neurons

27

4 functions neuroglia

Surround Neurons, hold in place
Supply nutrients/oxygen to Neurons
Insulate one Neurons from another
Destroy pathogens and remove dead Neurons

28

Where are Schwann cells

PNS

29

Where are oligodendrocytes

CNS

30

4 types neuroglia in CNS

Astrocytes
Oligodendrocytes
Microglia
Ependymal cells

31

2 types neuroglia PNS

Neurolemmocytes (Schwann cells)
Satellite cells

32

Describe Astrocytes

Star shaped with breaching processes
In CNS

33

2 functions Astrocytes

Hold Neurons to their blood supply
Contribute to blood brain barrier

34

Describe oligodendrocytes

Smaller than Astrocytes
In CNS

35

Role of oligodendrocytes

Form, maintain myelin in CNS
Similar role to Schwann cells in PNS

36

Microglia derived from what

Monocytes migrate before birth

37

Where are microglia found

Near blood vessels in CNS
Also mobile in the brain

38

What do microglia do when brain is damaged

Multiply

39

What else do microglia do

Phagocytic - clean up

40

Describe ependymal cells
Where are they found

Endothelial and epithelial cells which line walls of
4 ventricles of the cerebrum
Central canal of spinal cord

CNS

41

What do ependymal cells make
How is it circulated

Cerebrospinal fluid CSF

Beat their cilia to circulate it

42

What do Schwann cells produce

Myelin sheaths around neurons in the PNS - specifically the Axons

43

Describe myeline sheath

Multi-layered lipid and protein covering

44

Role of myelin sheath

Insulates axon
Increased speed of nerve impulse conduction

45

Covered axons are termed

Myelinated

46

Dendrite connections and most myelination is finished by what age

3
Malnutrition in infancy causes irreversible damage

47

Gap between Schwann cells along a neuron called

Node of ranvier

48

Function of nodes of ranvier

Increase speed of nerve transmission