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ESA4 - Nervous System > Glia & Neurones > Flashcards

Flashcards in Glia & Neurones Deck (17):
1

Give some examples of glial cells

Astrocytes, oligodendrocytes, microglia

2

What are the roles of astrocytes?

Nourish neurones, remove neurotransmitters, maintain ionic environment and help to form blood brain barrier

3

How do astrocytes help provide energy for neurones?

Glucose-lactate shuttle

Astrocytes take up glucose from the blood, convert it to lactate, release it and thus provide an energy substrate to neurons

Astrocytes are the only cells in the brain which can synthesise glycogen and thus can serve as an energy reservoir

4

How do astrocytes help to remove neurotransmitters?

They have transporters for transmitters such as glutamate which helps to keep the extracellular concentration low

5

How do astrocytes hel to buffer K+ in brain ECF?

Express high density of K+ channels

When neurons are active, they release K+ increasing the local extracellular concentration. Because astrocytes are highly permeable to potassium, they rapidly clear the excess accumulation in the extracellular space

6

What do oligodendrocytes to?

Myelinate axons in CNS

7

How do oligodendrocytes and schwann cells differ?

Oligodendrocytes = CNS, myelinate multiple axons
Schwann cells = PNS, can myelinate only one axon

8

What do microglia do?

Immunocompetent cells - become activate when they recognise foreign material and phagocytose

9

How is the blood brain barrier formed?

Tight junctions between endothelial cells, basement membrane surrounding capillary, end feet of astrocyte processes

10

Describe how neurotransmitters are released

Depolarisation in the presynaptic terminal opens voltage gated Ca2+ channels - Ca2+ enters terminal

Vesicles fuse and release transmitter

Neurotransmitter diffuses across synaptic cleft and binds to receptors on postsynaptic membrane

11

Give some examples of amino acid neurotransmitters

Glutamate, GABA, glycine

12

Give some examples of biogenic amine neurotransmitters

Acetylcholine, dopamine, serotonin, noradrenalin

13

What is the main excitatory neurotransmitter?

Glutamate

14

What is the main inhibitory neurotransmitter?

GABA

15

What are AMPA receptors permeable to?

Na+/K+

16

What are NMDA receptors permeable to?

Na/K+ and Ca2+

17

What do excitatory neurotransmitters cause?

Depolarisation of the postsynaptic cell by acting on ligand gated ion channels

Depolarisation causes more AP, increasing firing of neurons