Digestive & Excretory Systems

The Digestive System

Digestion Digestion is the processing of food. There are two types. Mechanical Digestion Chew Tear Grind Mash Mix Chemical Digestion Stomach acid Saliva

Peristalsis Peristalsis is the way food is pushed along by the movement of involuntary muscles. It only works in one direction. Peristalsis happens in the esophagus and in the stomach.

Stomach Shaped like a “J” Left side of body Mucous membrane for protection from stomach acid Functions Mixes food Stores food for later Starts digestion of protein and fats Activates some enzymes Destroys some bacteria Absorbs water

Small Intestine 20 feet long! Has three regions Duodenum Jejunum Ileum Absorbs 80% of water, plus vitamins, minerals, and proteins Food stays here 4 – 8 hours

Villi Villi are tiny finger-like extensions in the walls of the small intestine. They allow food to be absorbed faster.

Large Intestine 5 feet long Regions Food stays here 10 -12 hours Cecum – Appendix Colon Ascending Transverse Descending Rectum Anal canal Food stays here 10 -12 hours

Jobs of the Large Intestine Mechanical digestion Chemical digestion Absorbs water and vitamins Concentrates/eliminates wastes

Liver Detoxifies/removes drugs and alcohol Factory for antibodies and bile Stores vitamins and sugars until your body needs them

Gallbladder & Pancreas Storage tank for bile (a greenish-yellow liquid) that helps your body break down and use fats Located under your liver Shaped like a pear Helps you digest food by breaking down sugars Digests the food you eat Takes the nutrients out of your food so your body can use it

Gallbladder & Pancreas

Interesting Facts Food is in your digestive system for about 24 hours.

Your stomach stretches when you eat like a balloon being filled with air.

You have a trap door called the epiglottis to cover your windpipe when you swallow.

Your stomach mashes your food the way a baker kneads dough for bread.

The Excretory System

Jobs of the Excretory System Removes Excess water Urea: waste product from proteins Carbon dioxide Other wastes from our blood

Parts of the Excretory System Kidneys – filter out excess water and urea Ureters – tubes that take urine from the kidney to the urinary bladder. Urinary Bladder – a sack that stores urine. Urethra – small tube that leads urine out of the body. Lungs – filter out carbon dioxide from the blood Skin – excretes water as sweat, which contains some trace chemical wastes, including urea.

The Kidneys Located near hips on back side Every drop of blood in your body is filtered by your kidneys more than 300 times per day! Kidneys eliminate urea, minerals and excess water. Kidneys regulate the amount of water we need to maintain in our bodies.