Neuro Bb Barrier

Front 1

Autoregulation

Back 1

mechanism by which blood flow is maintained at a constant rate, despite changes in arterial BP

Front 2

Blood-brain barrier

Back 2

mechanism for selective control of movement from blood into internsitital space of brain

Front 3

Blood-CSF barrier

Back 3

mechanism for selective control of movement from blood into CSF

Front 4

brain receives what % of Cardiac Output?

Back 4

~15% (though it only makes up ~2% body weight)

Front 5

Average rate of cerebral flow

Back 5

50ml/100gm/min
Higher in Gray matter (70ml)
Lower in White matter (20ml)

Front 6

minimum CBF rate for gray matter is approximately:

Back 6

~15 ml/100g/min

before function begins to suffer

Front 7

what happens to brain arterioles at low pressures?

Back 7

these structures dilate, resulting in decreased vascular resistance and maintenance of CBF

Front 8

what happens to brain arterioles at high pressures?

Back 8

these structures constrict, increasing resistance and preventing excessive flow

Front 9

what allows arteriole response to high/low pressure?

Back 9

thought to occur via myogenic reflex, in arteriolar SM cells

Front 10

Increased pCO2 causes what changes in cerebral arterioles

Back 10

VASODILATION

Front 11

Decreased pCO2 causes what changes in cerebral arterioles

Back 11

VASOCONSTRICTION

Front 12

1mmHG change in pCO2 = what change in CBF

Back 12

2ml/100 gm/min change in CBF

Front 13

CBF is directly correlated to

Back 13

metabolic activity, via an undetermined vasoactive metabolite (adenosine, alctic acid, nitric oxide, etc..)

Front 14

factors potentially affecting regulation of CBF:

Back 14

sympathetic, neuropeptide, trigeminal, and serotonin inputs, viscosity (may affect CBF/O2 delivery coupling)

Front 15

factors determining viscosity of blood

Back 15

HEMATOCRIT
ERYTHROCYTE AGGREGATION
PLASMA PROTEIN CONCENTRATIONS

Front 16

site of the blood brain barrier

Back 16

at the brain capillaries, structurally/fxnally different than caps anywhere else in body

Front 17

how are brain capillaries different than other capillaries?

Back 17

-tight junction bt cells, no gap junctions or fenestrations
-few pinocytotic vesicles
-large number of mitochondria -astrocytic foot processes
-enzyme systems specific to cerebral vesels
-increased electrical resistance ax membrane

Front 18

GENERAL permeability factors

Back 18

Lipid solubility
Smaller Size
Less binding to serum proteins
Less polar

Front 19

Facilitated Transport systems
are important for what?
have what characteristics?

Back 19

important for getting insoluble substrates ax
-stereospecific
-have finite capacity
-are subject to competitive inhibition

Front 20

Transport Systems
Transport System: (Example Substrate)

Back 20

Hexose: (glucose)
Monocarboxylic Acid: (lactate)
Neutral Amino Acid: (phenylalanine)
Basic Amino Acid: (arginine)
Amine: (Choline)
Nucleoside: (Adenosine)
Purine: (Adenine)

Front 21

Ion Cotransport Systems

Back 21

Na+/Cl-
Na+/H+
Na+/K+
ATPase
etc..

Front 22

CSF is produced by

Back 22

choroid plexus

Front 23

Blood-CSF Barrier

Back 23

CSF is produced by the choroid plexus:
-capillaries have fenestrations
-barrier between the blood and CSF is at the epithelial lining of the choroid plexus
-choroids epithelial cells have tight junctions and few vesicles (like brain capillaries)