Digestive System

Chapter 24

Digestive System

Why do you feel hungry?

Because your brain receives a signal that your cells need ____________

ENERGY

Digestive System• Digestive System - the organs that break

down food so that the body can use itParts of the digestive tract

mouth pharynxesophagus stomachsmall intestine large intestinerectum anus

Parts of the Digestive System

Digestion• Digestion - the process of breaking down food so

it can pass through the digestive tract

2 types of digestion

1. mechanical digestion - crushing/mashing of food

2. chemical digestion - changing food into small particles to be absorb by the bloodstream

Digestion

• teeth - breaks down food to make it easier to digest (help mix food with saliva)

Digestion

• saliva - contains enzymes that begins chemical digestion (saliva changes carbohydrates into simple sugars)

• esophagus - squeezes the food and moves it into the stomach

Digestion

• Stomach - – squeezes the food with muscular contractions

(mechanical digestion)– Adds enzymes and acid to food (chemical

digestion)

Leaving the stomach the chyme is mixed with fluids from the liver and pancreas

Digestion

• small intestine - where the chyme is absorbed into the bloodstream by villi (small intestine is where most digestion takes place)

• liver - largest organ in the body– makes bile to break up fat

– stores nutrients

– breaks down toxins

Digestion

• gallbladder - bile is squeezed and moved into the small intestine (mechanical)

Digestion

• large intestine - particles too large to be absorbed into the blood are pushed into the large intestine

Urinary System

• Urinary system - organs that remove waste products from your blood

How the kidney filters blood

1.Blood enters the kidney (by a large artery)2.Tiny blood vessels bring blood to the

nephrons (nephrons remove wastes from the blood)

3.As the blood flows water and nutrients are returned to the blood

4.Concentrated wastes from urine are passed to the bladder

Urinary Problems

• Bacterial infections - bacteria gets into the bladder and cause painful infections

• Kidney stones - salts and wastes collect inside the kidneys, causes stones

• Kidney disease - damage to nephrons can affect normal kidney function causing kidney disease

The End