Neurones and Glia

Question 1

What are the reticular theory and neuron doctrine

Answer 1

Reticular theory - neurones fused together to form continuous reticulum or network

neurone doctrine - neurones weren’t continous but communicated via neurone to neurone contact

Question 2

How can neural tissue be seen and distinguished

Answer 2

nissil stain - cresyl violet stains nuclei and nissl bodies (RER) of neurone

golgi stain - silver chromate solution which stains neurons and their projections and cell bodies

Question 3

3 components of a prototypical neurone

Answer 3

cell body (soma)

axons - conducts AP / electrical impulses

Dendrites - recieve synaptic impulse,

Question 4

3 components of the axon

Answer 4

axon hilock - tapers away from soma to form initial segment of the axon

axon proper - axon branch to form axon collaterals (recurrent collateral is when axon bracnches returns to communicate with the same axon)

axon terminal - site at which the axon meets other neurones at a synapse

Question 5

which cells can myelinate axons

Answer 5

glial cells

myelin insulate axons

gaps within the myelin sheath are nodes of ranvir which are enriched with Na+ ion channels to boost AP transmission

Question 6

what are dendritic spines

Answer 6

specialised structures that are sensitive to type and amount of synaptic activity

important in neural communication

abnormal numbers leads to Alzheimer, schiz

Question 7

4 types of glial cells

Answer 7

astrocytes - star-shaped, numerous in extraceullar space, regulate chemical content of extracellular space between neurones, actively remove neurotransmitters from the cleft for normal function

microglia - phagocyte-like, remove nueronal and glial debris, ramified (active) to ameboid (scavenger). remove unnecessary synapases

ependymal cells - lining of ventricular sytem of brain and spinal cord, physical barrier separating brain tissue from CSF, osmoregulation

oligodendrocytes/schwann - provide myelin sheath, insulation and speed up nerve propagation (efficient AP), oligo = several axons in CNS & schwann = single axon in PNS

Question 8

4 types of glial cells

Answer 8

astrocytes - star-shaped, numerous in extraceullar space, regulate chemical content of extracellular space between neurones, actively remove neurotransmitters from the cleft for normal function

microglia - phagocyte-like, remove nueronal and glial debris, ramified (active) to ameboid (scavenger). remove unnecessary synapases

ependymal cells - lining of ventricular sytem of brain and spinal cord, physical barrier separating brain tissue from CSF, osmoregulation

oligodendrocytes/schwann - provide myelin sheath, insulation and speed up nerve propagation (efficient AP), oligo = several axons in CNS & schwann = single axon in PNS