Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

advanced neuro > lecture 3 astrocytes > Flashcards

lecture 3 astrocytes Flashcards

1
Q

astrocyes are most abundant macroglia constitute____of total brain volume

A

20-50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 identifiable types of astrocytes

A

1) Protoplasmic: (sheet-like; gray matter)
2) Fibrous: (stellate; white matter)
3) Radial: (thin unbranched; white matter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Protoplasmic located where and have what morphology

A

Gray matter astrocytes that
enfold cell bodies and processes
sheet-like; gray matter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Fibrous located where and have what morphology

A

stellate; white matter) scattered in of spinal cord and brain
• frequently form endfeet with capillaries
• run between myelinated fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Radial located where and have what morphology

A

(thin unbranched; white matter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

radial glia that are located in retnia

A

Müller Cells- elongated throughout the thickness of the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

radial glia that are located in cerebellum

A

Bergmann glia-Golgi epithelial cells –extend through the molecular layer to the cerebral cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

radial glia that are located in ependymal lining of ventricles (where cerebral spinal fluid is made)

A

Tanycytes: radial glia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

lamellipodium

A

is a cytoskeletal protein actin projection on the leading edge of the cell. It contains a quasi-two-dimensional actin mesh; the whole structure propels the cell across a substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

one way astrocytes help with neuron migration

A

Scaffolding, The neuron moves by release and reformation of the adhesion beneath the cell soma CONTACT DEPENDENT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what does Astrotactin 1 and 2

A

Neuron-glial adhesion molecules that mediates neuronal migration on glial fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how the function of Astrotactin 1 and 2 shown

A
  1. Antibodies to Astn1 can halt migration in vitro

2. Astrotactin null animals have delayed neuronal migration and behavioral defects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

_____ are the major motile structures involved in axon guidance and are located at the neurite tips.

A

Growth cones (GCs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Chemoattraction and Chemorepulsion in astrocytes is

A

a souluble factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Netrin is an example of a

A

Chemoattractant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

the landmark study by Banker, 1980

A

showed that you can culture neurons with astrocytes and astroccyte conditions media promotes neuron survial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

souluble factors released by astrocytes can

A

sustain growth and survival.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

astrocytes release ____ that are specific for subtypes of neurons

A

survial factors (ex BDNF, NGF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Axodendritic synapse

A

synapse on to dendrite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

axosomatic synapse

A

synapse on to cell body inhibitory inter neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

axoaxonic synapse

A

synapse on synapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

quantal contentis

A

the number of effective vesicles released in response to a nerve impulse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Astrocytes control the # of _______formed and

Participate in Synaptic Stability and ______

A

synapses,Maintenance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Astrocyte -Neurogenesis scaflolding main pts

A

Directing neuron migration via direct cell contact

Directing neuron migration via chemo-attraction and repulsion

25
Q

Astrocyte -Neurogenesis Survival main pts

A

Secretion of growth (survival) factors

26
Q

Astrocyte -Neurogenesis main pts Synaptogenesis

A

Control the # of synapses formed

Maintain neuronal synapses

27
Q

astrocytes Maintenance of Neuronal Homeostasis main ways (5) KNOW THIS

A 
K+ homeostasis 
pH regulation 
Neurotransmitter homeostasis (uptake and inactivation)
Redox balance  
and energy metoblism
28
Q

in a resting membrane potential k+

A

K+ is higher intracellularly and lower extracellularly

29
Q

during and action potential k+ is

A

K+ is lower intracellularly and higher extracellularly

30
Q

astrocytes help maintain K+ homeostatis mainly by

A

Na+/K+ ATPase—uptake in astrocytes 5-fold higher than in neurons

31
Q

astrocytes help maintain K+ homeostatis what is an channel assicated with this (important)

A

K+ channels (Kir4.1)

32
Q

astrocytes remove K+ from the ECM by

A

buffering K+ when put back into the ECM by astrocytes

siphoning K+ to the blood

33
Q

Kir4.1 expressed predominantly in brain

A

astrocytes and retinal Muller cell

34
Q

Kir4.1 allow large ______ at potentials negative to EK

and small, but significant, outward K+ currents at those positive to EK

A

inward K+ currents

35
Q

Why is maintaining extracellular K+ levels important?

A

Predispose the cell to hyper-excitability
Depolarization Block
(sizures

36
Q

Important as many cellular processes are pH dependent including

A

enzymes, NMDA receptor and affects redox state of a cell.

37
Q

Na+/H+ exchanger (1:1) : drives H+ out of cell by using energy of Na+ gradient

A

restores pHi normally and during acid loads

38
Q

) Cl-/HCO3- exchanger (1HCO3- out:1 Cl- in) Na+ -independent.

A

Primarily extrudes HCO3- restoring pHi during alkaline loads.

39
Q

Na+/Cl-/HCO3- (1Na+ in: 1HCO3- in: 1Cl- out): Na+ -dependent

A

Primarily drives HCO3- in during acid loads or following alkaline shifts extracellularly.

40
Q

Na+:HCO3- co-transporter (1:3) dominant mechanism for the steady state maintenance and restoration of pHi and pHe

A

acid shift extracellularly then HCO3- is extruded; if alkaline shift them HCO3- is taken up.

41
Q

in astrocytes PNT = Plasma Neurotransmitter Transporter function s

A

mainly to remove

neuron released glutamate.

42
Q

Physiological Functions of NT Uptake(3)

A

1) Help terminate synaptic transmission
2) Protect synapse from inappropriate activation by excess
transmitter (e.g., glutamate)
3) Provide transmitter precursors to neurons

43
Q

glutamate is an excitotoxin bcuz

A

is it builds up in EDM if over excites NMDA receptor

44
Q

The HCO3/CO2 buffer system is extremely important because

A

it can be rapidly readjusted in alkalosis and acidosis

45
Q

Oxidation is

A

the loss of electrons or an increase in oxidation state by a molecule, atom, or ion.

46
Q

Reduction is

A

the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion.

47
Q

Glutathione (GSN) major thiol-disulfide redox ___ of cells

A

buffer

48
Q

Glutathione (GSN) acts both

A

enzymatically and non-enzymatically.

49
Q

although ______ has more GSN per cells there are more ______ in the brain

A

microglia, astrocytes

50
Q

GSH helps with

A

redox reactions (helps remove radiacal O2 species), cell divison, antioxidant

51
Q

Thus, brain glucose varies directly with changes in

A

blood levels.

52
Q

is GSN increased or reduced in cultured neurons without neurons

A

reduced

53
Q

Glucose gains access to brain and into cells by specific carriers

A

(glucose transporters) -

54
Q

Astrocyte-Neuron ____Shuttle

A

Lactate

55
Q

Lactate produced locally within brain Crosses the blood brain barrier If given in vitro (experimental preps)

A

lactate consumed preferentially over glucose!

56
Q

EAAT- Excitatory Amino Acid Transporter (i.e., transports glutamate)- rely on Na+ gradient (does not require ATP for uptake but cell uses ATP to restore Na+ gradient). This type of pump is

A

s said to be electrogenic.

57
Q

GFAP- Intermediate filament protein -used as a marker to

A

distinguish astrocytes from other glial cells.

58
Q

Alexander’s Disease

A

Alexander’s Disease Caused my mutations in GFAP – glial fibrillary acid protein

advanced neuro (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions