The Digestive System

1. The Digestive System

2. Purpose of the Digestive System • Turning food into microscopic nutrients that can be absorbed through the intestinal lining • What is the toughest food that the human body might try to break down? • Fibre – made from plants (vegetables and grains)

3. 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!)

4. Structure of the Digestive Tract • http://medtropolis.com/virtual-body/

5. 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

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

7. 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

8. 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).

9. 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

10. Demo • Digestion of Fat -

11. 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)

12. 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?

13. The Circulatory System

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

15. 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

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

17. Structure of the Circulatory System • Video

18. Respiratory System

19. 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

20. 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

21. Respiratory System Structure

22. Gas Exchange

23. 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

24. 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

25. Musculoskeletal System

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

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

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

29. Muscles • Voluntary • Involuntary

30. Osteoporosis

31. Nervous System

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

33. 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.

34. 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.

35. 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

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

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

38. 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.

39. Functional MRI (Magnetic Resonance Imaging) • Detects electrical activity in the brain

40. Congenital Analgesia • Congenital Insensitivity to Pain • Malfunction of path of pain signals to the brain or the brain’s failure to interpret them • Very dangerous for children because they can hurt themselves without knowing it. • We feel pain so we don’t injure ourselves