Cells of the nervous system

Question 1

What is a neurone?

Answer 1

excitable cell that integrates and relays information in a circuit

Question 2

What are Glia?

Answer 2

Supporting cells that maintain homeostasis and assists neurone function

Question 3

What is Nissl staining?

Answer 3

Distinguish neurones from glia, all cell nuclei are stained, and neurones have nissl bodies - from rough RER and ribosomes

Question 4

What is the soma?

Answer 4

cell body of a neurone. It contains the nucleus, ribosomes, rough ER, Golgi apparatus and densely packed mitochondria.

Question 5

What is a golgi stain used for?

Answer 5

highlights the architecture of neurones better, only a percentage of neurones are stained at random. This stain allows you to see all of the 4 major compartments of a neurone – the soma, dendrites, axons and pre synaptic terminals

Question 6

Microtubules

Answer 6

run longitudinally down dendrites and axons, hollow tubes made of tubulin polymers

Question 7

Microfilaments

Answer 7

made of actin, run longitudinally and are membrane associated

Question 8

Neurofilaments

Answer 8

long protein molecules wound together - strong

Question 9

Axon Hillok

Answer 9

widest part of the axon, joined to the soma

Question 10

Axon initial segment

Answer 10

First generation site of action potentials

Question 11

Axon collaterals

Answer 11

Branches of the axon

Question 12

Axon terminal

Answer 12

The end of the axon.

Question 13

What is the length and diameter of an axon?

Answer 13

length - 1mm to 1m,

diameter - 1μm to 25μm.

Question 14

Immunohistochemistry

Answer 14

Used to find sodium channels in the axon

2 antibodies used, 1st binds to target ion channel, 2nd fluouresces and binds to first antibody - tags channel

Question 15

Specialisation of presynaptic axon terminal

Answer 15

no microtubules, synaptic vesicles, lots of mitochondria, specific proteins

Question 16

Unipolar neurons

Answer 16

Highly specialised, typically sensory, single extension from cell body, for example dorsal root ganglion

Question 17

Bipolar neurons

Answer 17

a neurone with only two extensions—an axon and a dendrite—that run from opposite sides of the cell body. Cells of this type are found primarily in the retina

Question 18

Multipolar neuron

Answer 18

High levels of convergence, a single axon and many dendrites (and dendritic branches), allowing for the integration of information from other neurons

Question 19

Pyrimidal neurons

Answer 19

neurons have distinct apical and basal dendritic trees with a pyramidal soma,

Question 20

Stellate neurons

Answer 20

Star shaped dendritic tree

Question 21

Astrocytes

Answer 21

Glial cells, glycogen stores of the brain, metabolise glycogen and supply lactate, endfeet take up glucose

Buffer extracellular K+

Part of blood brain barrier

Couple neuronal activity to blood supply

Question 22

Tripartite synapse

Answer 22

presynaptic neuron, post synaptic neuron and astrocytes

astrocytes can take in neurotransmitters that are present in synaptic cleft and recycle back to presynaptic terminal

Question 23

Synaptic pruning

Answer 23

Microglia remove unused synapses by phagocytosis

Question 24

Microglia

Answer 24

Control and remove tissue debris, allowing neuron growth

Question 25

Oligodendrocytes

Answer 25

Form myelin sheaths of CNS axons

Question 26

Schwann cells

Answer 26

Form myelin sheaths of PNS

One schwann cell provides one myelin segment to a single axon

Question 27

Function of myelin

Answer 27

Creates nodes of Ranvier (gaps in sheath) so saltatory conduction can occur

Limits flow of charge out of the axon through membrane - lateral resistance