1. ORGAN SYSTEMS WORKING TOGETHER
Section 3.5

2. Million 100 Million 1 Billion 1 trillion
60 trillion cells (60, 000, 000, 000, 000) in the body
Million
100 Million
1 Billion
1 trillion

3. ORGAN SYSTEMS
There are two main classifications of organ systems; those that:
 supply nutrients and remove wastes
 regulate the body

4. SYSTEMS FOR NUTRIENT SUPPLY AND WASTE REMOVAL
Respiratory System
Parts: trachea, lungs, alveoli, blood vessels in the lungs
Absorbs oxygen from the air and gets rid of carbon dioxide
Exchange of gases occurs in the blood vessels in the lungs, so it is connected to the circulatory system

5. SYSTEMS FOR NUTRIENT SUPPLY AND WASTE REMOVAL
Circulatory System
Parts: heart, arteries, veins, capillaries 
Distributes oxygen around the body and returns carbon dioxide to the lungs
Also distributes nutrients from the digestive system to the cells and collects waste products and brings them to the kidneys (excretory system)

6. SYSTEMS FOR NUTRIENT SUPPLY AND WASTE REMOVAL
Digestive System
Parts: mouth, esophagus, stomach, intestines, liver
Breaks down food, providing nutrients for cells (nutrients delivered to cells by the circulatory system)

7. SYSTEMS FOR NUTRIENT SUPPLY AND WASTE REMOVAL
Excretory System
Parts: kidneys, ureters, bladder, urethra
Collects waste from the blood system and excretes it as urine
Also regulates amount of water in body

8. Organ Systems

9. SYSTEMS FOR REGULATING THE BODY
Endocrine System
Produces hormones (chemical messengers) that travel to other organs and tell them how to adjust to our environment
Example. adrenaline (made by adrenal gland) causes the body to react quickly to danger

10. SYSTEMS FOR REGULATING THE BODY
Nervous System
Detects what is going on outside/inside the body and sends electrical messages throughout the body to your brain, your muscles, or your endocrine glands
The endocrine and nervous systems often work together to allow an organism to react to the environment