2.1 Neurones Flashcards Preview

NSN > 2.1 Neurones > Flashcards

Flashcards in 2.1 Neurones Deck (72):
1

What do glia do?

Support, nourish and insulate neurones

Also remove waste

2

Name 3 types of glial cells

Astrocytes

Oligodendrocytes

Microglia

3

What do astrocytes do? (4 points)

Provide structural support to neurones

Provide nutrition

Remove neurotransmitters

Helps form blood brain barrier

4

Why do neurones need astrocytes to provide them with energy?

Neurones do not store or produce glycogen

Astrocytes can store glycogen

5

What kind of molecules do astrocytes supply neurones with for the energy purposes?

Lactate

Glucose

6

What do astrocytes use to transport energy molecules to neurones?

Glucose lactate shuttle

7

What role do astrocytes play in terms of neurotransmitters?

Uptake transports to keep extracellular NT conc. low

8

Why is it important to remove glutamate from the synaptic cleft and terminate the response after a while?

Too much glutamate can be toxic to neurones

9

What is the buffer function of astrocytes and why is it needed?

Astrocytes take up excess K+

High levels of neuronal activity can lead to increased K+ conc. in brain ECF

10

What do oligodendrocytes do?

Myelinate axos in the CNS

11

What are the cells that are responsible for myelination in the CNS and PNS?

CNS - oligodendrocytes

PNS - Schwann Cells

12

What is the difference in myelination between Schwann cells and oligodendrocytes?

Oligodendrocytes - wrap around multiple neurones

Schwann Cells - wrap around a single neuron

13

What is the function of microglia?

Immunocompetent cells

Part of immune system in brain

14

How do microglia respond to foreign material?

Recognise --> activation --> Phagocytosis

15

What kind of cell are microglia?

Antigen presenting cells

16

How do brain capillaries differ from other capillaries?

Tight junction between endothelial cells

17

What surrounds brain capillaries?

End feet of astrocytes

Basement membrane

18

What is the function of the blood brain barrier?

Limits diffusion of substances

From blood to Brain ECF

19

How do substances get past the BBB?

Transported across

20

Why is it important that the CNS is immune privileged?

Because the skull is rigid

Inflammation would cause an increased ICP

21

What are the four main sections in a typical neuron?

Cell soma

Dendrites

Axon

Terminals

22

What must happen in a presynaptic neuron for neurotransmitter to be released?

Depolarisation

Voltage gated calcium channels open

Ca2+ floods in

23

Name the three chemical classes of neurotransmitters in the CNS?

Amino acids

Biogenic amines

Peptides

24

Name the major excitartory neurotransmitter

Glutamate

25

What kind of neurotransmitter is glutamate?

Excitatory amino acid

26

Name two inhibitory amino acid neurotransmitters

GABA

Glycine

27

What are the two types of glutamate receptors?

Ionotropic

Metabotropic

28

What are the two ionotropic glutamate receptors we need to know?

AMPA receptors

NMDA receptors

29

What type of protein is an ionotropic glutamate receptor?

Ion channel

30

What do ionotropic glutamate receptors let through?

Sodium and potassium ions

31

What does the activation of ionotropic glutamate receptors lead to?

Depolarisation

Increased excitability

32

What kind of protein is a metabotropic glutamate receptor?

GPCR

33

What excitatory neurotransmitters do to the postsynaptic cell and how do they achieve this?

Cause depolarisation

Act on ligand gated ion channels

34

What kind of depolarisation do excitatory neurotransmitters cause and what can this lead to?

Excitatory postsynaptic potential (EPSP)

Action Potentials

35

What are NMDA receptors permeable to?

Na+

K+

Ca2+

36

What are AMPA receptors permeable to?

Na+

K+

37

In what do process do glutamate receptors play a role in?

Learning and memory

38

What is long term potentiation?

Persistent strengthening of synapses based on recent patters of activity

39

What step is important for induction of Long term potentiation and how is this achieved?

Ca2+ entry through NMDA receptors

Strong, high frequency stimulation

40

What can happen if too much calcium enters through NMDA receptors?

Excitotoxicity

41

What is the main inhibitory transmitter in the brain?

GABA

42

What are the two inhibitory neurotransmitters in the brain?

GABA

Glycine

43

What protein forms part of both GABA and glycine receptors?

Integral Cl- channels

44

What is the effect of opening the Cl- channels of GABA and glycine receptors?

Hyperpolarisation

45

What kind of depolarisation does the activation of GABA and glycine receptors cause?

Inhibitory post synaptic potential

IPSP

46

What is the effect of inhibitory post synaptic potentials (IPSP)?

Decreased action potential firing

47

Besides GABA, what else can bind to GABA receptors?

Barbituates

Benzodiazepines

48

What kind of action do barbituates and benzodiazepines have?

Anxiolytic

Sedative

49

What are barbituates sometime used for?

Anti-epileptic

50

What are benzodiazepines used for?

Anxiety

Insomnia

Epilepsy

51

What do inhibitory interneurones in the spinal cord released?

Glycine

52

Give an example of when glycine is released in a reflex? Go through all of the steps in order to elicit this

Tap patella tendon
Quadriceps stretch
Detected by spindle
Afferents --> spinal cord
(Glutamatergic)
Efferents --> Quadriceps motor
(Acetylcholine)
Interneurones release glycine onto reciprocal muscles

53

What is the neurotransmitter at neuromuscular junctions?

Acetylcholine

54

What does acetylcholine bind to in the brain and what is (predominantly) the effect?

Nicotinic receptors

Muscarinic receptors

Excitatory

55

From where do the cholinergic pathways in the brain arise from?

Nucleus basalis

56

What are the cholinergic pathways of the brain involved in?

Arousal

Learning and memory

Motor control

57

What is degeneration of the cholinergic neurones in the nucleus basalis assocaited with?

Alzheimer's disease

58

What is the degeneration of dopaminergic pathways associated with?

Parkinson's

59

How can Parkinson's be treated?

Levodopa

60

Besides Parkinson's, what other condition is associated with dopamine dysfunction?

Schizophrenia

61

What is though to be the problem in Schizophrenia?

Too much dopamine release

62

Where do anti-psychotics act?

Dopamine (D2) receptor antagonists

63

What do you also give to someone who is already receiving levodopa?

Carbidopa

64

Why do you give someone receiving levodopa, carbidopa as well?

So L-DOPA (levodopa) isn't converted to dopamine in the peripheries and is transported across the BBB

dopamine cannot pass through BBB

65

What is levodopa also known as?

L-DOPA

66

What does noradrenaline act upon in the brain?

GPCR Alpha and beta adrenoceptors

67

Where do noradrengergic pathways arise from in the brain?

Locus ceruleus

68

When does the activity of noradrenergic neurones in the brain increase?

During behavioural arousal

69

What do amphetamines do and how do they achieve this?

Increases wakefullness

Increases the release of NA and dopamine

70

What is a deficiency of NA in the brain associated with?

Depression

71

What are the functions of the serotonergic pathways in the CNS?

Sleep/wakefullness

Mood

72

What do serotonin selective reuptake inhibitors treat?

Depression

Anxiety disorders