CHAPTER 48 SECTIONS 1 & 2PP 979-991

DIGESTIVE SYSTEM

Warm-up: 5/14•What is the pathway for the respirator system, starting with the mouth and ending with the lungs?•Draw and label the 4 chambers of the heart.

FUNCTION

• Breakdown of food into simpler molecules that can be absorbed by the body in one long tube from mouth to anus

NUTRIENTS

• 6 classes of nutrients:1. Carbohydrates2. Fats3. Proteins4. Minerals: help balance osmosis and the

function of certain cells (i.e. muscle cell)5. Vitamins: aid enzyme activity6. Water: accounts for half of your body

weight

PATHWAY

• Mouth Pharynx Esophagus Stomach Small Intestine Large Intestine (colon) Rectum

MECHANICAL VS. CHEMICAL DIGESTION

• Mechanical: physical breakdown of food• Chewing, peristalsis (moving

bolus down the esophagus), and stomach churning

MECHANICAL VS. CHEMICAL DIGESTION

• Chemical Digestion: Enzymes breaking down food into simpler forms (monomers)

DIGESTIVE TRACTMOUTH AND ESOPHAGUS

• Amylase (enzyme) is released from glands into saliva• Function: Breaks

down carbs to sugars

• Bolus (food ball) travels down esophagus to stomach

STOMACH

• Muscle contractions break bolus apart• Pepsin (enzyme) breaks down proteins• HCl (Hydrochloric acid) keeps stomach acidic so

the pepsin can work

LIVER

• Produces bile and secretes it into the stomach• Bile breaks down

fats

SMALL INTESTINE

• Chemical and nutrient absorption

GALL BLADDER

• Stores bile and secretes it into the small intestine

PANCREAS

• Secretes sodium bicarbonate (base) into small intestine to neutralize acid

LARGE INTESTINE/COLON

• Absorption of water, minerals, and vitamins

Salivary glands

StomachLiver

PancreasGall bladder

Small intestine Large intestine/colon

Esophagus