Digestive Excretory Systems 1 The Digestive System 2

Digestive & Excretory Systems 1

The Digestive System 2

Digestion • Digestion is the processing of food. • There are two types. – Mechanical Digestion • • • Chew Tear Grind Mash Mix – Chemical Digestion • Stomach acid • Saliva 3

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. 4

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 5

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 6

Villi • Villi are tiny finger-like extensions in the walls of the small intestine. • They allow food to be absorbed faster. 7

Large Intestine • 5 feet long • Regions – Cecum – Appendix – Colon • Ascending • Transverse • Descending – Rectum – Anal canal • Food stays here 10 -12 hours 8

Jobs of the Large Intestine • Mechanical digestion • Chemical digestion • Absorbs water and vitamins • Concentrates/eliminates wastes 9

Liver • Detoxifies/removes drugs and alcohol • Factory for antibodies and bile • Stores vitamins and sugars until your body needs them 10

Gallbladder & Pancreas Gallbladder • 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 Pancreas • 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 11

Gallbladder & Pancreas 12

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Interesting Facts Food is in your digestive system for about 24 hours. 14

Your stomach stretches when you eat like a balloon being filled with air. 15

You have a trap door called the epiglottis to cover your windpipe when you swallow. 16

Your stomach mashes your food the way a baker kneads dough for bread. 17

The Excretory System 18

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.