The Digestive and Excretory

Systems

DQ#27What do you know about the digestive system? List at least 5 items.

Write 2 questions about the digestive system that you don’t know the answer to, but want to learn about it.

What is DigestionDigestion is the process which

takes food and breaks it down into small pieces so it can be absorbed into bloodstream.

The Digestive System is a group of organs that work together to digest foods.

Types of DigestionThere are two types of

Digestion: • Chemical Digestion-Foods are broken down with the help of chemicals.

• Mechanical- Foods are physically broken down into smaller pieces.

The MouthDigestion begins in the

MOUTH through both chemical and mechanical digestion.

Mechanical Digestion – Teeth physically break down food particles into small pieces.

The MouthChemical Digestion –

Salivary glands secrete Saliva in the mouth which begins to digest starches.

Food is swallowed and moves into the ESOPHAGUS where it is pushed into the stomach.

StomachThe stomach also does both

mechanical digestion and chemical digestion.

Mechanical digestion -The stomach churns the food, breaking it down into small particles.

Chemical -many chemicals are secreted into the stomach to break down the food into tiny particles.

Small Intestine The SMALL INTESTINE is a

LONG, coiled tube (about 20 feet long).

Small fingerlike projections called VILLI cover the walls of the small intestine.

The villa absorb the nutrients from the food, and pass them onto the bloodstream.

The Helper Organs of the

Digestive System

Bile:• The LIVER produces bile• GALLBLADDER stores

bile. • Bile is secreted into the

small intestine to help digest fats

Enzymes:• The PANCREAS secretes

juices into the small intestine that help break down proteins, carbohydrates, and fats.

Solid WasteSome of the foods that

are not completely absorbed by the body, like fiber, produce solid waste which is then stored in the colon. After most of the water is absorbed by the body, the waste is called FECES, and is excreted through the anus.

Removing Wastes from the Body

Your Excretory System removes all waste from your body and controls water balance.

The three types of waste produced by the body are solids, liquids and gases.

The digestive system is responsible for producing liquid and solid wastes.

Liquid Waste KIDNEYS filter water and waste

from the blood. The substance secreted by the

kidneys is called urine, and it is sent to the bladder.

Urine is excreted from the body through the URETHRA