Glia

Question 1

What do glia do ?

Answer 1

support the network of neurones . Nourish, insulate and remove waste products

Question 2

What do astrocytes do?

Answer 2

the most abundant glia  :
Structural support 
Nutrition 
Remove neurotransmitters 
maintain ionic environment 
help form BBB

Question 3

What provides immune response in neurones ?

Answer 3

Microglia

Question 4

What are oligodendrocytes ?

Answer 4

provide insulation to neurones

Question 5

How do astrocytes provide energy for neurones ?

Answer 5

neurones cant store/produce glycogen

Astrocytes produce and shuttle it with glucose to the neurone

Question 6

How do astrocytes interact with neurotransmitters?

Answer 6

help keep ExCellular conc of neurotransmitters (glutamate) low via intake from transmitters

Question 7

What do astrocytes help maintain in terms of ions levels?

Answer 7

buffer the conc of K+ . k+ increased in high neuronal activity and astrocytes take in K+.

Question 8

What myelinates neurones in the CNS? what about the PNS?

Answer 8

CNS = Oligodendrocytes 
PNS = Schwann

Question 9

How do microglia cells work?

Answer 9

recognise foreign material , expand and phagocytose

Question 10

what are the 2 functions of the BBB?

Answer 10

Limit diffusion from blood to brain ECF

Maintain environment of neurones

Question 11

What 3 functions do brain capillaries have ?

Answer 11

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

Question 12

What is transported across the BBB?

Answer 12

Glucose, amino acids and potassium

Question 13

How is the CNS immune privileged ?

Answer 13

Rigid skull = not much volume increase
does not undergo rapid rejection of allografts
Microglia = antigen presenting cells
T cells can enter the CNS but inhibits the inflammatory T-cell response

Question 14

What are the 4 main sections of the neurone ?

Answer 14

Cell soma (body)
Dendrites
Axon
Terminals (Pre/postsynaptic)

Question 15

how is neurotransmitter released ?

Answer 15

Depolarisation in terminal = opening of VGCC . Ca2+ entry making vesicles fuse and release transmitter
diffuse across synaptic cleft and bind to receptor in postsynaptic membrane

Question 16

what are the 3 types of neurotransmitters and name an example of each type.

Answer 16

Amino acid = Glutamate, GABA, glycine
Biogenic amino = ACh , NA, Dopamine, serotonin and histamine
Peptides = CCK, Somatostatin

Question 17

what are the excitatory and inhibitory amino acid neurotransmitters ?

Answer 17

Excitatory = Glutamate
Inhibitory = Glycine , GABA

Question 18

What are the ionotropic glutamate receptors and what do they do?

Answer 18

AMPA - Na+/K+
Kainate - Na+/k+
NMDA - Na/k/Ca
allow the following ions to be permeable which depolarises = increases excitabilty

Question 19

What do glutamatergic Metabotropic receptors do?

Answer 19

G- coupled protein receptor-
IP3 and Ca2+ increase
inhibition of adenylate cyclase = decrease cAMP

Question 20

What do excitatory neurotransmitters do ?

Answer 20

depolarisation = EPSP leads to more APs

Question 21

What do AMPA receptors do ?

Answer 21

Initiate the fast depolarisation fro influx of Na+ when glutamate attaches . Allow NMDA receptors to activate

Question 22

What do NMDA receptors do and how are they activated?

Answer 22

NDMA activation requires Glutamate and depolarised post synaptic neurone
Allow Ca2+ entry and causes induction of LTP = important role in learning and memory

Question 23

How can AMPA receptors be affected from NDMA receptors ?

Answer 23

AMPS can up regulate when there is high activation of NMDA receptors

Question 24

What happens when too glutamate is produced?

Answer 24

Too much Ca2+ entry via NMDA so leads to excitotoxity

Question 25

What is the difference between GABA and glycine ?

Answer 25

GABA inhibits in brain

Glycine in brainstem and spinal cord

Question 26

How do GABAa and glycine receptors work?

Answer 26

Integrated Cl- ion channels open when bounded by neurotransmitter . Influx of Cl- = IPSP = decreased APs

Question 27

What drugs bind to GABA receptors and enhance the response ?

Answer 27

Barbiturates

Benzodiazepines

Question 28

What does glycine do in the spinal cord and brainstem ?

Answer 28

released by inhibitory interneurones to slow down APs

Question 29

Where is ACh used ?

Answer 29

ANS e.g. postganglinoic parasympathetic
Central brain - nictoninc and mus receptors
enhance release of other neurotransmitters

Question 30

Where in the brain is ACh used?

Answer 30

originates from basal forebrain / brainstem
diffuse projections to cortex
local interneurones in CStr

Question 31

What does ACh do in the brain?

What is a common condition of ACh neurone degeneration ?

Answer 31

arousal, learning , memory and motor control
degeneration = Alzheimer’s
Cholinesterase inhibitors used to alleviate symptoms

Question 32

What are the 3 dopaminergic pathways ?

Answer 32

Nigrostriatal pathway = Motor control
Mesolimbic = mood , arousal and reward
Mesocortical = same as above

Question 33

what is a theory for the pathology of schizophrenia ?

Answer 33

Dopamine release too high , seen in amphetamine users

Question 34

What does Carbidopa do ?

Answer 34

Inhibits AADC so L-DOPA is not converted to Dopamine

Question 35

How is dopamine transported to brain?

Answer 35

past BBB via LNAA and converted to dopamine from L-DOPA via AADC

Question 36

how do NA pathways in the CNS work?

Answer 36

Cell bodies in brainstem (Locus Cerlus) and there is diffuse release to cortex, hypothalamus and cerebellum

Question 37

What does NA do in CNS?

Answer 37

increase hood and state of arousal - amphetamines release NA and dopamine

Question 38

What do serotonergic pathways in the CNS do? What are SSRIs used for?

Answer 38

increase mood/ sleep

depression and anxiety