Blood Brain Barrier Text

Question 1

List 2 structures that account for the impenetrability of the BBB:

Answer 1

Tight junctions at brain capillary endothelial cells and decreased number of pinocytic vesicles

Question 2

BBB is induced by factors released by:

Answer 2

Feet of astrocytes

Question 3

3 important functions of the BBB accomplishes as a homeostatic barrier:

Answer 3

⇣ unregulated exposure to circulating neurotransmitters / keeps toxins & protein-bound drugs from entering CNS / protects against fluctuations in plasma ion concentrations

Question 4

If you suspect cancer or malignancy has disrupted BBB, what test will you order? / What will you infuse?

Answer 4

T-1 weighted MRI / Gadolinium

Question 5

What can temporarily disrupt the BBB? / Why would you want to do that?

Answer 5

High conc of mannitol injected into vertebral or internal intercostal arteries / So that hydrophilic molecules (i.e. chemo) can enter the brain parenchyma

Question 6

What does the term “circumventricular organ” refer to?

Answer 6

Areas of the brain that lack a BBB

Question 7

List the name of the 3 areas of the brain that normally lack a BBB (and where is each located & what ventricle is each associated with?):

Answer 7

Area postrema in the medulla (4th ventricle) / Median eminence of the hypothalamus (3rd ventricle) / Pre-optic area of the hypothalamus (3rd ventricle)

Question 8

Area Postrema / Median Eminence / Pre-optic area of the hypothalamus - why does each lack a BBB?

Answer 8

Measures noxious chemical level in blood and stimulates vomiting if too high / allows hypothalamus to release hormones into hypophyseal portal system / Measures glucose level of the blood

Question 9

How do hydrophilic molecules normally enter the brain parenchyma? Examples of each?

Answer 9

Specific transporters (i.e. d-glucose) and less-specific transporters (large, neutral amino-acid, LNAA)