Blood brain barrier ppt.

its about blood brain barrier

1. Blood brain barrier

2. BBB The blood-brain barrier ( BBB ) is a membrane that controls the passage of substances from the blood into the central nervous system. It is a physical barrier between the local blood vessels and most parts of the central nervous system itself, and stops many substances from travelling across it. The BBB is permeable to alcohol, and some heavy metals can cross the blood-brain barrier as well.

3. BBB

4. BBB

5. BBB

6. BBB Physiology In the brain, endothelial cells are packed much tighter together, due to the existence of zonula occludens (tight junctions) between them, blocking the passage of most molecules. The blood-brain barrier blocks all molecules except those that cross cell membranes by means of lipid solubility (such as oxygen, carbon dioxide, ethanol, and steroid hormones) and those that are allowed in by specific transport systems (such as sugars and some amino acids). Substances with a molecular weight higher than 500 daltons generally cannot cross

7. BBB Physiology Many drugs are unable to pass the barrier, since 98 percent of them are heavier than 500 daltons. hormones generally do not penetrate the brain from the blood, except at the ' circumventricular organs The blood-brain barrier is an effective way to protect the brain from common infections. as antibodies are too large to cross the blood-brain barrier, infections of the brain when they do occur can be very serious and difficult to treat.

8. BBB break The BBB can be broken down by: Hypertension (high blood pressure): high blood pressure opens the BBB Development: the BBB is not fully formed at birth. Hyperosmolitity: a high concentration of a substance in the blood can open the BBB. Microwaves: exposure to microwaves can open the BBB. Radiation: exposure to radiation can open the BBB. Infection: exposure to infectious agents can open the BBB. Trauma, Ischemia, Inflammation, Pressure: injury to the brain can open the BBB.

9. Drug Delivery and the Blood-Brain Barrier The BBB is permeable to small and lipophilic (fat-loving) molecules (up to 800 atomic mass units), but larger molecules are not transported across unless there is an active transport system available Thus this is one of the stumbling blocks for drug delivery An additional problem is the very effective drug efflux systems (P-gly-coprotein – P-gp ), which pump the drug back out of cells.

10. drug delivery across BBB