Gut Function (III) Flashcards
What are the 3 parts of the small intestine
Duodenum
Jejunum
Ileum
What lays on top of the muscle and mucosa layers on the small intestine
Large villi made up of one cell thick epithelial cells
What are the gaps in between villi called
Crypt
What types of cells cover the villi
Goblet cells and enterocytes(microvilli epithelium)
What is the apical membrane where microvilli are on enterocytes called
Brush border membrane
Which areas does digestion of carbs lipids and proteins take place
Lumen
Apical brush border membrane
Cytosol of enterocytes
Where does absorption take place eg of carbs lipids water naCl
At enterocytes
Where are secretions of fluid and naCl happening
Crypt
Which polysaccharides does amylase from liver work on
Glycogen and starch
What does amylase convert glycogen and starch into
Dextrins - short chains of glucose
Where are disaccharides broken down and which enzymes
Brush border membrane
Maltase, sucrase , lactase
After digestion by brush border membranes, what monosaccharides are absorbed into the blood down enterocytes
Galactose fructose and glucose
Why can amylase only convert starch and glycogen into disaccharides and not mono
Because amylase is an endo enzyme so can’t break external bonds
How do glucose and galactose get through the apical membrane
Na cotransporter
Higher na outside of the cells
What is the na glucose transporter called
SGLT1
How is the na removed out of the cell when cotransported in
K/na ATPase on baso lateral membrane
How does glucose and galactose and fructose get removed out the baso lateral membrane
Glut 2 (facilitated diffusion)
How is fructose transport into the apical membrane different
Facilitated diffusion via GLUT5
Exit via glut 2
What digests proteins in the lumen
Pancreatic and gastric proteases
Which gastric protease is an endopeptidase in lumen
Pepsin
Which pancreatic protease is both an endo and exo peptidase in lumen
Trypsin
What kind of enzymes are those in brush border and cytosol
Endo exo and dipeptidases
What gets absorbed if the epithelium isn’t leaky (proteins)
Peptides via AT
Amino acids via SAT
What allows for active transport of peptides into apical membrane
Low ph (high H) on outside
H is used for energy to carry peptides in to cytosol
