Barriers Flashcards
give 3 examples of general barriers
- skin
- intestines
- exocrine glands
- kidney
- meningues
give 3 examples of specialised physical barriers
- blood-brain
- blood-testes
- placenta
- blood-retina
what links epithelial cells together?
junctional complexes e.g. Claudin
what do claudins do?
determine the tightness and selectivity of cellular junctions for parvocellular trasnport
what’s parvocellular transport?
transport of substances between cells
what’s transcellular transport?
transport of substances within cells
what does transcellular transport require?
polarity
describe the 2 stages of salivary secretion?
Primary secretion- Acinar cells- ions flow in from blood to lumen, followed by water by osmosis through aquaporins
secondary secretion- duct cells allow the blood to reabsorb Na+ and Cl-, however they have no aquaporins so no water leaves
this gives non-salty saliva- hypotonic compared to plasma
what is polarity?
difference in concentration/ electrical gradients
what is primary active transport?
using energy from ATP dephosphorylation to transport substrate
what is secondary active transport?
ions moving using the concentration gradient set up by primary active transport
what are the 2 important brain-barriers?
- blood- brain barrier
- chloroid plexuses (blood- CSF barrier)
what do 1st gen. antihistamines lead to?
sedation/drowsiness due to CNS effects
what do 2nd gen antihistamines lead to?
no sedation/drowsiness due to reduced CNS effects
what’s different between 1st and 2nd gen antihistamines ?
both are lipid soluble so can cross BBB (2nd are actually more),
however gen.2 are much better substrates for p-glycoprotein for removal from CNS
