Paul De Bank Flashcards
What’s the three main roles of the epithelia
Protection, absorption, gas exchange
What are the two types of epithelia
One layer= simple
>1 layer= stratified
Give an example of a squamous epithelium
Alveoli
Name four specific types of epithelial cells
1) Squamous epithelium
2) Stratified squamous epithelium
3) columnar epithelium
4) cuboidal epithelium
Name two types of drug absorption
1) transcellular pathway
2) paracellular pathway
Define paracellular pathway
Between adjacent epithelial cells
What’s rate limiting in the paracellular pathway?
The tight junctions
Name 4 types of junction between cells
1) tight junctions
2) adherens junctions
3) desmosomes
4) gap junctions
What’s the most common cell junction?
Desmosomes
What types of molecules can be absorbed via paracellular pathway
Small hydrophilic molecules
What’s transcellular pathway
Occurs across the epithelial cells
Name 4 ways a molecule can undergo transcellular pathway
1) passive diffusion
2) aqueous pore
3) facilitated diffusion
4) active transport
Is passive diffusion via transcellular pathway the most common pathway of drug absorption?
YES
What three things cause the small intestine to have a large surface area
1) folds of kerckring
2) villi
3) microvilli
Where in the body is the main site of food and dug absorption
Small intestine mainly the jejunum while the ileum absorbs remaining nutrients
The bile ducts release secretions from the pancreas and the gall bladder including what enzymes
Trypsin Chimotrypsin Elastase Carboxypeptidase Amylase Lipase
Ingestion of food stimulates the secretion of what two things in the stomach
HCL
pepsinogen
What’s the role of HCL in the stomach
Acts as an antiseptic and promotes the conversion of pepsinogen to pepsin (a potent proteolytic enzyme)
What’s another names for fasted state
Interdigestive
What’s another name for fed state
Digestive
What occurs in the interdigestive state
MMC (migrating motor complex)
Phase 1: quiescence
Phase 2: irregular contractions
Phase 3: house keeper waves
List 8 factors that affect gastric emptying rate
1) meal volume
2) type of meal
3) physical state of meal
4) chemicals
5) drugs
6) disease
7) body position
8) exercise
There’s a high expression of what enzymes in the small intestine?
CYP450
What is the p-gylcoprotein efflux pump?
170Kda protein found in the apical membrane of cells in the small and large intestine
Name 5 strategies for improving oral drug delivery
1) increase drug lipophilicity use of prodrugs
2) p-GP inhibitors
3) cytoadhesion
4) mucoadhesive patches
5) new delivery systems eg protective coatings, nanoparticles
Name three ways you can improve membrane permeability
1) use of prodrugs
2) lipidisation (attach lipid to drug)
3) penetration enhancers (partially solubilise epithelial membrane)
