A&P 2 Chapter 6 Discussion Paper

Identify and describe the six major processes involved in gastrointestinal activity. Ingestion which takes in food, propulsion which contains peristalsis(alternates the contracting and relaxation) and segmentation(movement of food back and fourth across an organ mixing with the digestive juices),mechanical digestion(breaks food into smaller peices),chemical digestion(breakdown large molecules into their building blocks; occurs in the mouth, stomach, & small intestines),absorption(transport of nutrients from the blood or lymph), and defection(elimination of waste in a solid form)

Identify three ways the small intestine is modified to increase the surface area for digestion and absorption. The plicae circulares, villi, and microvilli are modifications of the small intestine for digestion and absorption. The plicae circulares are circular folds of the mucosa and submucosa. They force chyme to move spirally through the lumen. The villi are fingerlike projections of the mucosa. They increase the absorptive surface area. Microvilli are projections of the plasma membrane of the absorptive cells of the mucosa that bear intestinal digestive enzymes. They also increase surface area and enhance absorption.

Outline the usual pathway for digestion and absorption of triglycerides (fats)
Triglycerides are broken down to free fatty acids and monoglyceride by lipase. Bile salts bind to lipids which help transport them in the small intestine. In the small intestine colipase help expose lipids to lipase for further breakdown to micelles. These small lipids can now enter the apical membrane of the small intestine and form chylomicron which then are released into the lymphatic system or small lipids can enter the circulatory system. Why is it necessary for the stomach contents to be so acidic? How does the stomach protect itself from digestion?
HCl is necessary for the activation and optimal activity of pepsin, and it