NBSS: (neuroscience) blood-CNS barriers, homeostasis and regulation

Question 1

describe E. goldmanns first and second experiments

Answer 1

therefore based off where they were injected, goldman hypthesised that there must be a barrier of some sort between blood and CNS

Question 2

in the 1960s using electron microscopy and molecular tracers such as horseradish peroxidase, what was proved to be the barrier between the blood and CNS?

Answer 2

brain capillaries

Question 3

how many arteries supply the brain with blood?

Answer 3

4

Question 4

what are the 2 types of arteries that supply the brain with blood

Answer 4

2 carotid arteries, 2 vertebral arteries

Question 5

where do the carotid and vertebral arteries merge?

Answer 5

circle of willis at the base of the brain

Question 6

what emerges off of the circle of willis

Answer 6

plial arteries

Question 7

what 4 vessels do plial arteries subdivide into

Answer 7

penetrating arteries
penetrating arterioles
intracerebral arterioles
capillaries

Question 8

what are 2 key characteristics of brain capillary network

Answer 8

• complexity
• high density of vessels

Question 9

what is the capillary wall of brain capillary cell formed of

Answer 9

a SINGLE endothelial cell joined by tight and adherent junctions at the paracellular cleft

Question 10

what other components make up the neurovascular unit other than the brain capillary endothelial cells

Answer 10

microglia
oligodendrocytes
astrocytes
pericytes
basement membrane
glycocalyx

Question 11

what is a key component of astrocytes

Answer 11

glial fabrillary acidic protein

Question 12

how do astrocytes communicate with eachother

Answer 12

via end feet

Question 13

what are 2 key parts of astrocytes

Answer 13

perivascular sheet
glia-limitans (end feet)

Question 14

functions of astrocytes

Answer 14

Question 15

whats the difference in permeation across blood brain barrier in:
simple diffusion
passive diffusion
transporters influx
transporters efflux
endocytosis

Answer 15

Question 16

in cerebral capillaries, the paracellular movement of molecules is restricted by what

Answer 16

intracellular junction complexes

Question 17

what is the intracellular junction complex composed of

Answer 17

adherens junctions
tight junctions

Question 18

what is the difference in restriction between adherens junctions
tight junctions

Answer 18

adherens = NON restrictive
tight = RESTRICTIVE

Question 19

what are the 3 functions of the cerebral capillary endothelium

Answer 19

1. PHYSICAL BARRIER - continuous strand of tight junctions
2. TRANSPORT/ SELECTIVE BARRIER - high level of transporters, reduced number of vesicles
3. METABOLIC BARRIERS - enzyme systems

Question 20

describe the lipophicility of heroin and its subsequent effects when taken

Answer 20

Question 21

which molecule has a greater ability to cross the blood brain barrier than you’d predict

Answer 21

D glucose

Question 22

what are 2 types of SLC transporters

Answer 22

• facilitated diffusion transporters
• secondary active transporters

Question 23

what is the structure of p-glycoprotein

Answer 23

2 repeating units

joined by linka group

12 transmembrane domains

the 2 possible drug bunding domains are found between transmembrane. 5/6 and 11/12

Question 24

3 types of endocytotic mechanisms

Answer 24

NON SELECTIVE
1. fluid phase endocytosis
vesicle forms and anything within the vicinity of fluid is trapped and the vesicle fuses with membrane and transfers it across

SELECTIVE
2. receptor-mediated endocytosis
- insulin and transferring bind to its specific receptor, enveloped in vesicle and transferred and released
3. absorptive transcytosis
- positively charged molecule interacts with negatively charged glycocalyx, the positively charged molecule then engulfed in vesicle, its transferred and released

Question 25

what 2 things form the blood CSF barrier

Answer 25

• choroid plexus (4 types)
• arachnoid membrane

Question 26

3 functions of choroid plexus

Answer 26

• produces CSF
• synthesises polypeptides
• contributes to regulating brain ISF

Question 27

what causes alzheimers disease

Answer 27

alzheimers disease toxin is amyloid β, the removal process is damaged