Blood-Brain Barrier

Question 1

Blood-Brain Barrier Definition

Answer 1

Endothelial cells lining the microvasculature of the brain to form a barrier between circulation and interstitial fluid
Physical, transport, and metabolic barrier
Function is to maintain a stable microenvironment for the proper function of neurons within CNS

Question 2

Structure of BBB

Answer 2

Complex tight junctions

Lack of pinocytic vesicles

Question 3

Movement of Substances across the Blood-Brain Barrier

Answer 3

Paracellular aqueous pathway - severely limited by tight junctions
Transcellular lipophilic pathway - O2, CO2, Ethanol, Barbituates
Transport proteins - Nutrients and wastes,L-DOPA, chemotherapy agents (may or may not be energy dependent)
Recepter-mediated transcytosis - Insulin, transferrin
Adaptive transcytosis - Plasma proteins (albumin)

Question 4

Pathology of Blood-Brain Barrier

Answer 4

Down regulating proteins that contribute to the tight junctions
Breaking down the basal lamina around the capillaries
Up-regulating or down-regulating transporter proteins
Influencing the secretions of astrocytes

Question 5

Examples of pathology

Answer 5

Stroke, trauma, infection/inflammation, Multiple sclerosis, HIV, Alzheimer’s, Parkinson’s, Epilepsy, Tumors, Pain

Question 6

Circumventricular Organs

Answer 6

Areas of the brain that lack the blood-brain barrier