Digestive and Excretory System Overview By Rebecca K. Fraker
Digestive System
The Mouth: The Trip Starts Here The teeth cut pieces of food into smaller portions. Saliva shoots in and begins digestion.
Down the Hatch For a proper start, chew food until it is ground small and mixed with the saliva. Then swallow! Salivary glands
Food is pushed down this pipe into the stomach esophagus The food is squashed by muscular contractions and acid is added. Proteins start to be digested by enzymes
Duodenum Small intestine Large intestine Rectum Anus
The enzymes help to break the food into smaller particles. Gall bladder stores bile In the duodenum digestive juices from the pancreas are added and bile which is made in the liver is also added. The enzymes help to break the food into smaller particles.
The bile helps to neutralize the acid from the stomach and also helps to break the fat into little droplets. Stores Bile
Trace the path of the food Trace the path of the food. Notice that after the food goes into the duodenum, it goes into the small intestine, circles around and THEN takes a loop in the large intestine.
Small Intestine And Enzymes at Work In the small intestine the enzymes help to break the food up into smaller particles. Proteins ----- amino acids Carbohydrates ------ glucose Fats ---- fatty acids and glycerol
The tiny particles are then absorbed into the blood stream. The particles diffuse into the blood and are carried all round the body.
In the large intestine the water that is needed is taken back into the blood. Food is now all digested.
The solid waste or feces is stored in this part of the large intestine or rectum before passing out the body through the anus.
Anus – the solid waste passes out of the body through this special muscular part. The waste, called feces, can show what a person (or other organism) has eaten.
SUMMARY Food is chewed to make digestion easier. The mouth starts to digest the food and the stomach makes it into a liquid. The small intestine finishes digesting the food and the tiny dissolved food particles move into the blood. Undigested food passes out through the large intestine.