Blood Brain Barrier (BBB)

Question 1

What is the BBB ?

Answer 1

A highly selective semipermeable membrane barrier that separates the blood from the brain

Question 2

What is the cellular composition of the BBB ?

Answer 2

Tight Junction
Endothelial cells
Basement membrane

Question 3

Capillary forms 95% of BBB. TRUE or FALSE

Answer 3

TRUE

Question 4

What is the function of Tight junction in BBB ?

Answer 4

Prevents solute movement b/wn endothelial cells

Question 5

Astrocyte foot processes secrete paracrines that form tight junctions. TRUE or FALSE

Answer 5

TRUE

Question 6

Tight junction of BBB is composed of Integral membrane proteins ad Cytoplasmic accessory proteins. TRUE or FALSE

Answer 6

TRUE

Question 7

Give examples of Integral membrane proteins

Answer 7

Claudin
Occludin
Junctional adhesion molecule

Question 8

Give examples of Cytoplasmic accessory proteins

Answer 8

Cingulin
Zonula Occludens (ZO)

Question 9

Identify differences between BBB and Capillaries of Peripheral Organs

Answer 9

• BBB;
  contains more tight junctions
  has higher tight junction resistance (>1000)
  has abundant amount of mitochondria (mitochondria is rare in capillaries of PO)
  has no clefts (unlike capillaries of PO)
  highly selective transport
  Deficient vesicular transport (abundant in Capillaries of PO)
  Rare pinocytic vesicles (abundant in capillaries of PO)

Question 10

Name the blood CSF barrier

Answer 10

Choroid plexus

Question 11

State functions of CSF

Answer 11

• Provides mechanical protection
• maintains stable extracellular environment for the brain
• removes some waste product
• Nutrition

Question 12

BBB is not a wall. TRUE or FALSE

Answer 12

TRUE

Question 13

Name BBB transport mechanisms

Answer 13

• Passive diffusion
• ABC transport efflux
• Solute carriers (SLC)
• Transcytosis (Receptor or Adsorptive mediated)
• Mononuclear cell migration

Question 14

Water is able pass into the brain. TRUE or FALSE

Answer 14

FALSE. Water can’t enter the brain because it’s charged

Question 15

Give examples of substances that can pass through the BBB

Answer 15

• Glucose
• Lactate
• Amino acids

Question 16

Give examples of molecules transported via receptor mediated transcytosis (RMT)

Answer 16

• Insulin
• Erythropoietin (EPO)
• Transferrin

Question 17

Give examples of molecule(s) transported via adsorptive mediated transcytosis (AMT)

Answer 17

Albumin

Question 18

Albumin is the most common protein in the blood. TRUE or FALSE

Answer 18

TRUE

Question 19

Describe properties of molecules that can enter the brain

Answer 19

• Small
• Lipid soluble
• Low charge

Question 20

State the function(s) of the BBB

Answer 20

• Protects brain from foreign substances of the blood
• Protects brain from hormones and neurotransmitters
• Transports nutrients into the brain
• Moves toxins out of the brain
• Maintains constant environment for the brain
• Essential for normal brain functions

Question 21

The BBB is permeable to small, lipophilic molecules (up to 400Da). TRUE or FALSE

Answer 21

TRUE

Question 22

Larger molecules are transported across BBB only via Active transport system. TRUE or FALSE

Answer 22

TRUE

Question 23

A large proportion of drugs cannot cross the BBB. TRUE or FALSE

Answer 23

TRUE

Question 24

Drug efflux systems (P-gly-coprotein -P-gp) pump drug back out of cells. TRUE or FALSE

Answer 24

TRUE

Question 25

Strategies for drug delivery into the brain include delivery ‘through’ or ‘behind’ the brain. TRUE or FALSE

Answer 25

TRUE