Monday March 1, 1999
Announcements: Review Session tonight at 110 Wartick Lab, from 6:30-7:30

Lecture notes:

Aerobic respiration occurs in the mitchondrion.
Pyruvate converstion and Krebs Cycle are the second stage in aerobic respiration. (Glycoysis was the first)

Pancreas: (An accessory organ) Ducts from the pancreas lead into the small intestine.
The pancreas has endocrine and exocrine functions.

Exocrine Functions: digestion (Exocrine means that secretions are carried by a duct)

Bicarbonate: buffering

Trypsin: breaks proteins into peptide fragments

Chymotrypsin: breaks proteins into peptide fragments.

Pancreatic amylase: breaks carbohydrates into disaccharides

Carboxypeptidase: breaks peptides into amino acids

Lipase: breaks triglycerides into free fatty acids and monoglycerides.

Pancreatic nucleases: breaks DNA and RNA into nucleotides.

Endocrine Functions: regulates blood glucose uptake by cells for use and for storage. "Islet" cells secrete insulin and
glucagon.

Insulin: enhances glucose uptake by cells for use and for storage

Glucagon: stimulates liver cells to convert glycogen to glucose. It also inhibits conversion of glucose to
glycogen.

Liver: Digestive functions (This is but one of many functions of the liver)

Secretion of bile

Bile Emulsifies fat (breaks it into smaller globules) so it can be digested more easily by lipase.

Bile is stored in the gall bladder.

Secretion of bicarbonate for buffering

Small Intestine: Intestinal Villi (Villus, s.) increase surface area for absorbtion

Microvilli (thread-like projections on the surface of each cell) further increase surface area.

Functions: digestion
movement of food
Absorption of nutrient molecules

Secretions: mucus - lubrication and protection
hormones - regulation of digestion
disaccharides - break disaccharides into monosaccharides
aminopeptidases - break peptides into amino acids
intestinal nucleases - break nucleic acids into nucleotides

Large Intestine: no "digestion" takes place here.

Functions: storage and concentration of feces reabsorption of water into the internal environment

* Feces contain: undigested matter
water
bacteria
some unabsorbed material