Digestive System

Describe the GI tract/ alimentary canal

oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus

What are the accessory organs of the digestive system?

Teeth, tongue, salivary glands, liver, gallbladder, pancreas

Where does digestion begin?

In the mouth, mechanical digestion begins. Mechanical digestion is the physical breakdown of food. Mucus in saliva contains the enzymes amylase and lipase to initiate chemical digestion of starch and lipids

What are the enzymes amylase and lipase?

Amylase- catalyzes the hydrolysis of starch (carbs), basically causes the breakdown of starch

Lipase- enzyme primarily produced by the pancreas that breaks down fats

Define deglutition

swallowing of the bolus

Describe peristalsis

Muscle contractions that move food through the digestive tract

Define chemical digestion

The process where enzymes break down food particles into simple chemicals that can be used by the body

Define chyme

The semifluid mass of partly digested food that moves from the stomach to the small intestine

Describe the function of the stomach

Stores food, churns food with secretions (mechanical digestion), initiates protein digestion

What are the three main secretions of the stomach?

Mucus- lines the stomach

Hydrochloric acid- creates an acidic environment

Pepsinogen- converted to pepsin, an enzyme that helps chemically digest proteins in the acidic environment

What is the function of the small intestine?

Digestion of proteins, lipids, and carbohydrates

Absorption of their products, water, electrolytes, vitamins, and bile salts

The duodenum produces brush border enzymes (protease, lactase, disaccharides, and bicarbonate)

Describe villi and microvilli

Villi- fingerlike folds of the mucosa to increase surface area and nutrient transport

Microvilli- microscopic folds of the epithelial cells making up the villi, form the brush border, is for maximum absorption

Describe the function of the large intestine

Absorption of water, electrolytes, and vitamins. Absorption of vitamin K and production of vitamin K, folic acid

Formation, storage, and expulsion of feces

Define the liver

The organ that produces bile, regulates glycogen storage, and performs other bodily functions

Describe the hormones Ghrelin and Leptin

Ghrelin= induces hunger

Leptin= causes the sensation of satiety

Describe the hormones insulin and glucagon

Insulin- induces cellular uptake of glucose, thus lowering blood glucose levels

Glucagon- stimulates the breakdown of stored glycogen