What is an “Organ?”

1. What is an “Organ?” - An organ is a structure having a definite form and performing a definite function or functions.

2. Organs may perform several different functions and perform duties for more than one system.

3. The liver helps the digestive system, cardiovascular system, immune system, and urinary system. Without organs are bodies cannot function properly.

4. The heart is a single organ, but has two sides that perform extremely different tasks to keep our blood circulating properly.

5. Lymph Nodes – Enlarged bunches of lymphatic tissues located at various points along the lymph vessels.

6. This is where lymph is cleansed of debris and microbes. When you have an infection, the lymph nodes may become swollen.

7. Peyer’s Patches - Group of lymphatic tissue in the lower part of the small intestine. These continually clean your digestive system so that it can work efficiently.

8. Tonsils and Adenoids are accumulation of lymphatic tissue in your throat to protect the entrance into your body from being invaded by pathogens.

9. Pathogens – Disease-causing microorganisms.

10. Spleen – Largest lymphatic organ. • About the size of your fist and is located behind your stomach and beneath your diaphragm. • Filters out and disposes of dead cells and microbes in the blood and serves as a storage tank for extra blood

11. Thymus- Immature lymphocytes manufactured in the bone marrow are transported here. • Located behind your breastbone and between your lungs. • This is where the lymphocytes mature and then are sent to the spleen, and the rest of lymphatic system to complete their growth and do their job.

12. Lungs- Large spongy organs of the respiratory system. • Located in the thoracic cavity. • Right lung is bigger than the left lung and has 3 lobes, while left lung only has 2 lobes.

13. Pleura - A thin slippery membrane that covers the lungs. • Helps reduce friction when we breathe.

14. Alveoli - Tiny air sacs inside our lungs that are the vital functioning units of the respiratory system. • - 300 million inside our lungs. • Where exchange of gases between blood and air takes place.

15. Diaphragm – Dome shaped structure that aids in the breathing process by contracting to give you added space in your thoracic cavity. • - Skeletal muscle, but not entirely voluntary. • Signaled to contract by the phrenic nerve.

16. Small Intestine – After food from the stomach enters this organ the liver and pancreas help it to complete the digestion process. • Absorbs nutrients and sends waste to be eliminated. • Consists of 3 sections and is around 10 feet long. When you die, will relax and can be 20 feet long.

17. Duodenum – First 10-inch section of the small intestine. • Here, food is mixed with digestive juices and secretions from the pancreas and the liver.

18. Jejunum – Next portion of the small intestine. Is about 4-feet in length.

19. Ileum - Last section of the small intestine, and is about 5 ¼ feet. • This is where the Peyer’s Patches are located.

20. Villi – hair like tubes that cover the inside wall of your small intestine. • Absorbs the digested food and transfers it to the capillaries of your cardiovascular system, where it gets transferred to the cells.

21. Colon – 5-foot long tube where indigestible remains of food mixture go. • Contains helpful bacteria which keep harmful bacteria from grouping up and causing an infection in your body. • These bacteria also produce helpful vitamins.

22. Rectum – Where indigestible food is sent to after the colon. Here is where the waste gets ready to be eliminated as feces.