Blood Brain Barrier

Question 1

Who taught the lecture on BBB?

Answer 1

Dr. Elwood K. Walls

Question 2

What are special properties of BBB?

Answer 2

1. less endocytosis
2. less vesicular transport
3. tight junctions
4. specific transport systems
5. astroglia endfeet

Question 3

What percent of the body’s energy goes to the brain?

Answer 3

20%

Question 4

What prevents toxic or unwanted substances circulating in the blood of the brain?

Answer 4

tight control of brain extracellular fluid or BBB

Question 5

What are unique properties of the BBB?

Answer 5

CNS vessels are continuous nonfenestrated vessels

Question 6

Who found the BBB?

Answer 6

Paul Ehrlich and Edwin Goldmann found the BBB when they noticed that vital dyes got in the brain only when injected directly into CSF

Question 7

What role do endothelial cells play?

Answer 7

they connect by tight junctions to control what substances enter; they lack fenestrations and pinocytotic vesicles

Question 8

What can pass endothelial cell membrane?

Answer 8

lipid-soluble gases (O2) and lipophilic substances (alcohol and psychoactive drugs)

Question 9

How do metabolites get across epithelial cells?

Answer 9

specific transport mechanisms (ie. transporters, ion channels, exchangers)

Question 10

What does BBB maintain?

Answer 10

It maintains homeostasis of CNS extracellular fluid and sustains optimal microenvironment for neurons and glia

Question 11

What relationship do astrocytes have with the blood vessels?

Answer 11

They have endfeet that wrap portions of the blood vessel. They transport materials from blood vessels to the neurons

Question 12

How do we get lifesaving drugs into the brain?

Answer 12

1. Hyperosmotic solutions
2. Microcatherization
3. Microbubbles
4. Attaching to carriers

Question 13

What areas of the brain do not have a BBB? Why?

Answer 13

circumventricular organs, CVOs (hypothalamus and pituitary glands) because they need to secrete substances that enter blood stream or to respond to blood-borne substances

Question 14

What are disorders of BBB?

Answer 14

1. brain tumors and brain metastases (leaky vessels)
2. Bacterial Meningitis (breakdown of barrier)

Question 15

What produces CFO?

Answer 15

choroid plexus of lateral, 3rd and 4th ventricles

Question 16

Where does CSF flow to from choroid plexus?

Answer 16

3rd ventricle, 4th ventricle, central canal as well as subarachnoid space between Pia mater and arachnoid maembrane

Question 17

Where is CSF reabsorbed?

Answer 17

In the arachnoid granulations to be cleared into venous blood

Question 18

How often is CSF replaced?

Answer 18

every 6 horus

Question 19

What is composition of CSF similar to? What contains more carbon dioxide?

Answer 19

plasma or brain ECF; CSF has more carbon dioxide

Question 20

Functions of CSF?

Answer 20

1. provides a pressurized fluid-mechanical cushion to the brain
2. removing harmful metabolites
   3.Distribution of polypeptide hormones

Question 21

Diagnostics and medical applications

Answer 21

1. Cloud appearance and elevated presence of leukocytes indicates infection
2. In multiple sclerosis immunoglobulin concentration is elevated

Question 22

What is a hydrocephalus shunt?

Answer 22

It is a shunt designed to relieves pressure in hydrocephalus; infants have brain distorting due to blocked flow of CSF in the cerebral aqueduct