The Digestive System

1. The Digestive System

2. What is the purpose of the digestive system?

3. Purpose of the Digestive System • To break down food to provide nutrients and water to the body, and expel waste • What is the toughest food that the human body might try to break down? • Fibre – made from plants (vegetables and grains)

4. How does food get broken down? • Mechanically • Mouth chews food to break it into smaller pieces • Stomach churns • Chemically • Liver produces bile to mix water and fat together for digestion • Gastric acid is produced by the cells of the stomach lining (it would burn your hand!)

5. Mouth Esophagus Liver Stomach Gall Bladder Pancreas Large Intestine Small Intestine Colon Rectum/Anal Sphincter

6. Parts of the Digestive System

7. http://www.youtube.com/watch?v=NddZ5ftQb0Q

8. Parts of the Digestive System

9. Parts of the Digestive System

10. Stomach Cells – How would these help the stomach lining? Mucus

11. How do these stomach cells work? • Fit tightly together to provide a barrier to substances • Columnar epithelial cells secrete mucus which provides a lining in the interior of the stomach which protects against acid

12. Take a minute… • Complete the flow chart using your organ system diagram • Start with the stomach • End with the blood stream/Out of the body • What organs do the water/nutrients/waste have to go through to get to the bloodstream/exit?

13. How does the digestive system give nutrients to the blood stream? • What do we call exchange points in the circulatory system? • Capillaries • Where do nutrients get absorbed? • Intestines (Small – Food, Large – Water) • Where else do these exchange points exist? • Every cell and the lungs

14. The Process of Nutrient Absorption • Food is broken down in the stomach to microscopic nutrients and released into small intestine dissolved in water • As the nutrients pass the villi, diffusion occurs through the extremely thin walls of the villi • Nutrients enter the capillaries and then start to circulate through the blood stream

16. The Importance of the Sphincter • Without a sphincter, the digestive track is really just a hole through your body • Sphincter – a ring of muscle that holds a biological opening closed • Over 50 different sphincters in the human body

17. Two Types of Sphincter’s • Voluntary - Controllable • Rectum – both voluntary and involuntary sphincter’s • Sphincter Urethrae - Urinary sphincter

18. 2 Types of Sphincter’s • Involuntary - Not in your control • Ileocecal valve – closes off the small intestine so that food that has not fully broken down may not pass • Sphincter pylori – Holds food in the stomach until it is thoroughly mixed with stomach acid

19. Olestra • Fat substitute used in the 1980’s • zero calories, zero grams of cholesterol and zero grams of fat • gastrointestinal symptoms — including diarrhea, loose stools, nausea, gas • Olestra sometimes causes underwear staining • “greasy, hard-to-wipe-off fecal matter” • anal leakage (leakage of liquid olestra through the anal sphincter).

20. My Roomate • He did not have an esophogeal sphincter • Always got heart burn (acid moving up from your stomach into your esophagus) • Had a muscle from his leg fashioned into a sphincter to prevent it • http://www.youtube.com/watch?v=9bnIuKiHdDE

21. Demo • Digestion of Fat -

22. What’s wrong with me Doc? • Day 1: • Pain in stomach area • Answers: • Lot’s of fibre, good amount of veggies, not too much red meat • 2 days of on and off pain • Bowel movements – 1-2/day (regular)

23. What’s wrong with me Doc? • Day 2: Pain moves down and to the right side • Excrutiating pain when I walk • Some nausea and vomiting • Answers: • I know I have collitis. Do I have collitis? How could I test for it?

24. The Circulatory System

25. Purpose of the Circulatory System • Transports nutrients and oxygen to cells • Transports waste and carbon dioxide away from cells

26. Getting Around the Body • The heart pumps blood through the body • It pumps blood to the lungs to exchange gases and comes back to the heart • The heart then pumps blood around the rest of the body to transport gases to the cells

27. Veins vs. Arteries • Arteries – Pumps blood AWAY from the heart • Veins – Brings blood back to the heart

28. Capillaries – Act as an exchange point for gases and nutrients • These happen in the: • Lungs • Intestines • Every single cell in the body

29. Structure of the Circulatory System • Video

30. Respiratory System

31. Purpose of the Respiratory System • To provide all cells in the human body with Oxygen and remove Carbon Dioxide produced as waste by each cell

32. Fact • You breathe 15 times per minutes and move 10,000L of air in and out of your lungs each day • With every breath, you breath in at least one particle of air that Gandhi breathed in when he was alive

33. Respiratory System Structure

34. Gas Exchange

35. Carbon Monoxide Poisoning • When we breathe in Carbon monoxide, it takes the place of oxygen on the red blood cells • Since RBC’s cannot carry oxygen, the tissues in the human body start to malfunction • The brain relies on oxygen and is one of the first organs affected • You will feel nausea, head aches, loss of consciousness and more

36. Breathing • You breath without having to ask your body to do so • If you hold your breath too long, when you fall unconcious, your body will start to breathe again

37. Musculoskeletal System

38. Purpose • The musculoskeletal system supports the body, protects delicate organs and makes movement possible

39. Muscles • Bundles of long cells. • Contract and expand when signalled by nerve cells. • Skeletal muscle attached to bone by tendons

40. Muscles • Muscles contract – get shorter and thicker.

41. Muscles • Voluntary • Involuntary

42. Osteoporosis

43. Nervous System

44. Purpose of the Nervous System • To sense the environment and coordinate an appropriate response

45. Nervous System • The nervous systemis made up of the brain, spinal cord,and peripheral nerves. • It senses the environment and coordinates an appropriate response. • The core of the nervous system is the brain and the spinal cord.This is called the central nervous system.

46. Nerves are bundles of special cells called neurons,surrounded by connective tissue. • Neurons arecommunication specialists that send informationaround the body using electrical signals. • There are approximately 100 billion neurons in the human brain.

47. Neuron Facts Human brain has over 100 billion neurons If lined up, they’d make a line over 600 miles long Neurons do not undergo mitosis Signals can be sent as high as 180 miles/hour

48. The peripheral nervous systemconsists of the nerves that carry the signals between the central nervous system and the body.

49. Human Body is an Electrical Circuit • Let-go Voltage

50. Reflexes • Reflexes are actions that do not require the involvement of the brain: they occur without conscious thought. • The spinal cord acts as a short cut for reflexes.