Appendix C BBB

Question 1

tight junctions

Answer 1

• capillary cells are packed together in brain to prevent unwanted things from going in/out of blood
• astrocytes regulate things from getting in/out (feet of astrocytes)

Question 2

what gets through?

Answer 2

• lipid soluble substances
• some gasses (O2)
• steroids (sex hormones/cortisol)
• albumin (not lipid soluble)
• -its a protein carrier that carries lipid soluble substances
• -steroids bind to albumin in blood so they dont freely diffuse out of capillaries at unwanted locations. they unbind once they have been transported to right place, freely diffuse through
• transport systems
• -amino acids (L-system and A-system)
• -ions (eg sodium/potassium pump)

Question 3

circumventricular organs

Answer 3

• no BBB
• regions in brain that dont have a BBB
• ventricles, nucleus, pituitary
• make it easier for things to freely move in and out
• pituitary needs to regulate hormone concentrations, ventricles need to exude waste

Question 4

circumventricular organs

Answer 4

3 detecting, 2 secreting

• subfornical organ (regulates H2O intake)
• organum vasculosum of the lamina terminalis (detects and regulates fluid balance)
• post pituitary (secretes hormones)
• area postrema (detects toxins, initiates throwing up)
• pineal body (secretes melatonin)