2. Any remaining substances are fermented and release gas
3. Some vitamins are synthesized by bacterial action
Flatulence
When carbs are fermented and there is an excessive amount of gas
Absorption and Feces Formation
1. Colon absorbs water, electrolytes, and some vitamins as chyme remains for 3-10hrs
2. Feces consist of water, inorganic salts, sloughed-off epithelial cells, bacteria, products of bacterial decomposition, and undigested portions of food
Defecation Reflex
1. Rectal wall distends and stretch receptors send sensory nerve impulses to the sacral spinal cord
2. Motor impulses travel back to the descending colon, sigmoid colon, rectum, and anus
3. Longitudinal rectal muscles, abdominal muscles, and the diaphragm contract and the internal anal sphincter opens
Normal bowel movements
Range between 2-3 per day or as minimal as 3-4 per week
Mechanical Digestion: Defecation Reflex
1. Interactions Animation: Mechanical Digestion in the Large Intestine
2. Defecation: Animation section 4
Phases of Digestion
1. Cephalic phase: Smell, sight, thought, and taste of food stimulates gastric secretion and motility
2. Gastric phase: Neural and hormonal mechanisms promote secretion and motility
3. Intestinal phase: Neural and hormonal mechanisms occur once food enters the small intestine
Hormonal Control of Digestion
Interactions Animation: Hormonal Control of Digestive Activities
