Module B-07 Flashcards Preview

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Flashcards in Module B-07 Deck (54)
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1

Which are the 3 extracellular fluid compartments and the volume of each?

1)Plasma
2)Interstitial fluid
3)CSF

2

Where is majority of fluid of body found ?

Intracellular 60%

3

Where is CSF found?

1)Intraventricular (23ml)
2)Subarachnoid space (67-117 ml)

4

volume of CSF

90-140ml

5

4 functions of CSF

1) Maintains Extracellular environment
2)Removes metabolites from CNS
3)regulated cerebral blood flow and pulomonary ventilation
4)Cushions brain

6

How does CSF influence cerebral blood flow and pulmonary ventilation?

Owing to changes in its pH

7

What is present in high levels in CSF compared to plasma?

Cl-, Mg++ and Na+ (only slightly higher)

8

What is present in low levels in CSF compared to palsma

protein, glucose, K+ ,Ca++

9

At what levels is lumbar puncture done

L3/L4 or L4/L5

10

What is relevance of a lumbar puncture?

1) analysis of CSF
2) measurement of intracranial pressure

11

4 adverse effects of Elevated intracranial pressure (ICP)

1) Nausea
2) Bradycardia
3) Systemic hypertension
4) Papilledema

12

What does the Monroe-Kellie Doctrine state?

An increase in volume of one component (e.g., brain, blood, or cerebrospinal fluid) will elevate pressure (ICP) or decrease the volume of one of the other elements.

13

What are the 3 components of the Blood Brain Barrier

1)Endothelial cells,
2)Astrocytic endfeet
3)Capillary basement membranes

14

What are 2 characteristics of capillaries of the brain

lack fenestrations and have tight junctions to prevent paracellular flow (only Transcellular flow takes place)

15

What can pass through the BBB?

Small hydrophobic molecules, blood gases, small uncharged polar molecules,urea and glycerol

16

The higher the Oil/water partition coefficient the ____ (less/more) effective the transfer of the solute across the BBB

more

17

What are 2 substances moved by facilitated diffusion across the BBB

L-DOPA and Glucose

18

Ratio of solubility in oil versus water predicts

transcellular transfer of solutes into CNS

19

What transporter is used in BBB endothelial cells for glucose transport?

GLUT-1

20

What transporter is used in BBB endothelial cells for L-DOPA transport?

Neutral amino acid carrier

21

How does glycine cross the BBB (brain to blood)

Na+-dependent cotransporter ( secondary active transport)

22

What can cause the tight junctions of BBB to become leaky?

1)Hypertension (high blood pressure)
2) Hyperosmolality
3) Trauma, ischemia, inflammation or pressure
4) Infection

23

How does hyperosmolarity cause leaky endothelium

hypertonic infusions shrink endothelial cells and disable tight junction but this is reversible

24

Clinical use of hyperosmolarity with BBB

may permit delivery of lipid-insoluble drugs to
the CNS

25

What differs circumventricular organs from rest of CNS

lack tight junctions in capillaries and thus lack
the BBB

26

Name the Circumventricular organs

1)Area postrema
2) Median eminence
3) Neurohypophysis
4)Organum vasculosum
5)Pineal body
6) Subcommissural organ
7)Subfornical organ

27

What cells line the ventricles

Ependymal cells (group1)

28

What cells form the choroid plexuses?

Secretory Ependymal cells (group 2 )

29

where does CSF circulate?

the ventricles, the spinal canal and the entire
subarachnoid space

30

Where does CSF come from?

1) Choroid plexus (70%)
2)specialized secretory ependymal cells of the subcommisural organ (30%)