The Digestive System Ch. 15 Sect. 2

Digestive System Functions Your food goes through 4 steps when entering the body: ingestion, digestion, absorption, and elimination. Ingestion is the act of eating, or putting food in your mouth. Digestion is the mechanical and chemical breakdown of food into smaller particles and molecules that your body can absorb and use. Absorption is when water and nutrients are taken in by the cells. Elimination is when undigested food is eliminated

Types of Digestion 2 types of digestion: Mechanical and Chemical 1. Mechanical- food is physically broken into smaller pieces. 2. Chemical – chemical reactions break down pieces of food into small molecules. Enzymes are proteins that help break down larger molecules into smaller ones. Enzymes can speed up or catalyze the rate of chemical reactions.

Organs of the Digestive System 2 parts of the Digestive System: Digestive Tract (food touches) and the other organs that help the body break down food. Digestive Tract: Mouth, Esophagus, Stomach, Small Intestines, Large Intestines, Rectum and Anus Other Digestive Organs: Salivary glands, liver, gallbladder and pancreas.

Mouth & Esophagus Mechanical Digestions starts in the mouth. Salivary glands produce saliva. Saliva has an enzyme that breaks down carbohydrates. Also, neutralizes acidic foods. Esophagus – tube that connects the mouth to the stomach. Food moves through the esophagus using peristalsis (muscle contractions)

Stomach & Small Intestines Stomach’s function is to temporarily store food. Aids in Chemical digestion and makes stomach acid. Food turns into chyme in the stomach. Most chemical digestion & nutrient absorption occurs in small intestines. Small intestines are covered with villi.

Pancreas, Liver & Gallbladder Pancreas produces amylase (enzyme) that breaks down carbohydrates. Pancreas secretes a substance that neutralizes stomach acid. Liver produces Bile. Bile makes it easier to digest fats. Gallbladder stores bile.

Large Intestines, Rectum, & Anus Once undigested food leaves the small intestines, it enters the large intestines (part: colon) Large intestines absorbs water and liquids. The materials left after liquid absorption (feces) become a solid waste stored in the rectum. Anus releases the fecal matter.