BSC 424 Human Physiology

They are centered around the gastrointestinal (GI) tract, essentially a long tube that moves food, water, and electrolytes from the outside of the body to the inside.

ATP: originates from the breakdown of complex molecules. The origianl source of those molecules is our food.

Complex carbs, fats, and proteins: pathways of cellular metabolism and ATP production

1. must be able to breakdown food from a solid to simple molecules w/out causing damage to the tissues themselves. 2. it must move these molecules from inside the lumen of the gut (outside the body) to the inside of cells and into circulation. 3. it must release large quantities of fluid to aid in the digestive process and then reabsorb that fluid. 4. it must be able to operate literally non-stop (can't fatigue)

6-7 liters

Carbs- glucose proteins- amino acids fats- fatty acids

1. Digestion 2. Absorption 3. Motility 4. Secretion

The chemical and mechanical breakdown of foods into smaller units that then can be absorbed or transported across the GI wall

The active or passive transfer of substances (molecules) from the lumen of the GI tract, across the gut epithelium, through the extracellular fluid, and into circulation.

Movement of material through the GI tract and mechanical mixing to maximize exposure to enzymes and acids

The release of substances that are involved in digestion. Includes enzymes, bile, mucus, bicarbonate solution, water, electrolytes, and acids. Also, hormones and paracrines (signaling substances.

Total= 15 feet small & large intestine= 13 feet

Mucosa Submucosa Muscularis Externa Serosa

The mucosa is the inner most layer, with a large surface area. It is made up of the Mucosal Epithelium, the Lamina Propria, & the Muscularis Mucosa

For protection, absorption, and secretion.