Digestive System Notes Function:

1. Digestive System Notes Function: • Breaks down food into smaller molecules that can be absorbed and used by the body Click Me http://www.mennellmedia.co.uk/VideoProjects/ToiletTales/ToiletTales.html

2. Major Organs: • Mouth—where digestion begins • Chewing is a mechanical process that breaks food into smaller particles • Saliva mixes with food and amylase (enzyme) breaks down carbohydrates into simpler molecules

3. Click Me

4. Esophagus—passage to stomach • Peristalsis—muscular contractions to move food through esophagus • Epiglottis—small flap that protects food from going down trachea; guides food into esophagus Click Me http://www.mennellmedia.co.uk/VideoProjects/Peristalsis/Peristalsis.html

5. Stomach—large muscular sac that mixes food from esophagus with digestive fluids • Mucus is produced to lubricate and protect the stomach wall • Thick liquid of partially digested food is called chyme

6. Sphincters—valves at each end of the stomach that close to prevent food from escaping in either direction while being mixed by contractions of stomach wall • Heartburn (also indigestion or acid reflux) occurs when these valves (sphincters) do not close completely

7. Small Intestine—chyme enters small intestine from the stomach • Digestive fluids from pancreas and liver enter the small intestine • Food is chemically digested and absorbed into blood by villi—small fingerlike projections that line the small intestine

9. Large Intestine—chyme moves from small intestine into large intestine • Water is absorbed through the wall of the large intestine, leaving behind only undigested waste called feces • Waste is stored in the rectum until expelled from the body through the anus

10. Accessory Organs: • Pancreas—produces insulin to regulate blood sugar levels and produces enzymes to break down carbohydrates, proteins and fats • Liver—detoxifies chemicals • -produces bile—bile breaks down fats • Gall bladder—stores bile until it is needed Click Me http://www.mennellmedia.co.uk/VideoProjects/ThePlanEdit5/ThePlanEdit5.html

13. Excretory (Urinary) System Function: • To remove waste products from the blood • Helps maintain homeostasis by regulating water content of the blood

14. Major Organs: • Kidneys (renal = kidney) • Paired organs that remove cellular wastes, toxins and excess water from blood • Every 45 minutes kidneys filter all the blood in your body • Filtered blood leaves kidneys and returns to circulation • Sometimes excess salts or minerals in the urine crystallize and form kidney stones. When kidney stones block the ureters, they cause great pain.

15. Ureters—tubes that carry urine from kidneys to urinary bladder • Bladder—muscular sac where urine is stored temporarily before being excreted • Urethra—tube that carries urine from bladder to the outside

16. Structure of the Urinary (Excretory) System Right Kidney Left Kidney Left Ureter Bladder Urethra

18. Endocrine System • Function: • Control, coordinate and regulate most of body’s activities by releasing hormones into the blood • Hormones are chemicals produced in one part of the body that affect another part of the body

19. Major Glands: • Pituitary gland • Master gland that controls all other endocrine glands • Secretes growth hormone during childhood (Tumors on pituitary glands can cause gigantism.)

20. ?

21. Thyroid gland • Controls metabolic rate of all cells • Metabolism is the sum total of all chemical reactions that occur in living organisms in order to maintain life

22. Thymus—stimulates T-cell development for immune system • Adrenal gland—releases adrenalin and other chemicals to help body respond to stress (fight or flight response)

23. United Streaming – Adrenaline: Flight or Fight Response 6:36 min

24. Ovaries—produce estrogen and progesterone required for development of female sex characteristics and for development of eggs • Testes—produce testosterone for sperm production and development of male sex characteristics

26. Reproductive System Function: • Formation of new individuals • Puberty—period of rapid growth and maturation during which reproductive system becomes fully functional

27. Female Reproductive Organs: • Ovaries • Paired organs that produce one mature egg per month • Ovulation is process of mature egg being released from ovary—usually 10-14 days after completion of menstrual cycle

28. Fallopian tubes • Tube through which egg travels from ovary to uterus • Egg can be fertilized as it travels through Fallopian tubes • Uterus—muscular organ where embryo develops • Vagina—birth canal that leads from uterus to outside of body

30. Male Reproductive Organs: • Testes—produce sperm • Scrotum—sac that holds the testes • Epididymis—where sperm mature and are stored

31. Vas deferens—tube through which sperm moves from epididymis to urethra • Eventually vas deferens merges with urethra • Penis—delivers sperm and urine to outside of body • Prostate gland and seminal vesicles • Produce seminal fluid to help sperm survive • Inflamed prostate gland squeezes urethra and causes problems with urination

32. Vas deferens