Untitled Notes

Located in the inferior part of the left upper quadrant.
- Head near the midline; tail extends to the left.

Functions: Absorption of water from indigestible food; formation of compact feces.
Major components: cecum, colon, rectum, anal canal.
- Cecum: Joins the small intestine at the ileocecal junction.
- Ileo is the last part of the small intestine.
- "Sickle" refers to the first part of the colon.
- Mucocelcal junction where they come together.
- Appendix: Approximately 9 cm long, often surgically removed.
Colon: About 1.5 meters long; comprises ascending, transverse, descending, and sigmoid regions.
Rectum: Straight tube from sigmoid colon to anal canal.
- Anal canal lasts 2-3 cm; the final segment of the digestive tract.

Food takes 18-24 hours to pass through the large intestine, yielding water, indigestible food, and microbes.
Microbes synthesize Vitamin K, which is essential for blood clotting.

Feces Formation: Water and salts absorption, secretion of mucus, and activity of microorganisms contribute to feces formation.
Stores feces until defecation, with strong contractions (mass movements) every 8-12 hours, propelling contents forward.
Digestion: Involves mechanical and chemical breakdown of food, primarily occurring in the stomach and small intestine.
Peristalsis: The movement that helps transport food through the digestive tract.

Carbohydrates: Need to be broken down to simple sugars.
- Digested from polysaccharides to disaccharides by salivary and pancreatic amylase.
- Disaccharides are further broken down into monosaccharides on the intestinal epithelium.
Glucose Absorption: Glucose taken in through co-transport with sodium into epithelial cells then transported via the portal vein to the liver for storage as energy.

Triglycerides are broken down into fatty acids and monoglycerides.
- Micelles form around the fats due to bile salts, facilitating their diffusion into intestinal epithelial cells.
- Inside epithelial cells, fatty acids and monoglycerides are reassembled into triglycerides and coated with proteins to form chylomicrons.
- Chylomicrons are released via exocytosis into lacteals, entering the lymphatic system and then bloodstream.

Lipoproteins: Water-soluble and lipid-soluble molecules for transport in blood and lymph.
- Types:
- Chylomicrons: Facilitate fat transport.
- LDL (Low-Density Lipoprotein): Bad fat, transfers fat from the liver to arteries, leading to fat deposition in vessels.
- HDL (High-Density Lipoprotein): Good fat, transports fat from arteries to liver for removal.

Pepsin: Enzyme in stomach that initiates protein digestion.
Pancreatic enzymes (trypsin, chymotrypsin, and carboxypeptidase) are secreted in inactive form into the small intestine where they are activated.
Absorption of Amino Acids: Peptides are broken down into tripetides or individual amino acids absorbed through epithelial cells by various co-transport mechanisms.