This document summarizes the key functions of the digestive and excretory systems. It explains that digestion breaks down food into smaller molecules that can be used by the body, starting in the mouth and continuing in the stomach and small intestine. The kidneys, lungs and skin are involved in excretion, with the kidneys removing waste from blood to produce urine for excretion. The kidneys also help maintain electrolyte and fluid balance, and release hormones to regulate bones, blood cells and pressure.

2. •Water helps digest food, eliminate
wastes, maintain blood pressure, regulate
body temperature, keep skin moist
•Carbohydrates- main source of energy for
you body
•Proteins- raw materials used for growth
and repair of body’s cells and tissues
•Fats- provides energy and key
components in cell membranes
•Minerals- your body needs small
amounts of minerals and vitamins to main
•Vitamins- organic molecules that work
with enzymes to regulate cell functions,
growth, and development ,maintain
homeostasis

4. •Digestion- process by which large molecules in food are
broken down into smaller molecules that can be used by
body

5. •Digestion begins in the mouth and continues in
the stomach
•Chemical Digestion through the saliva, which
contains an enzyme called salivary amylase that
starts the digestion of starch into sugar.

6. •Chewed food in mixed with saliva and travels down
esophagus to stomach

7. Stomach continues digestion- digestive juices are “churned”
to produce smaller pieces
1. Turns into liquid mixture called chime
2. Stomach empties into small intestine

8. Small intestine- long narrow tube in which most digestion takes place
1. Enzymes from pancreas, and bile from liver enter to help digestion

9. 2. Nutrients absorbed in small intestine
a. Lining of intestine is ridged and folded to increase surface
area for absorption
b. Folds covered with fingerlike projections called villi

10. Water is absorbed and solid waste are eliminated by the large intestine
1. Large intestine (colon)- absorbs about 1 liter of water a day.
2. Also contains many types of bacteria

11. The excretory system eliminates nonsolid wastes from the body
1. Eliminates nonsolid wastes through sweat, urine, and exhalation to
help maintain homeostasis
a. Wastes include toxic materials, excess water, salts, CO2, urea,
minerals, and vitamins
b. Main organs are skin, lungs, kidneys

12. Lungs remove excess CO2 and water vapor through
exhalation
Skin releases excess water and salts

13. Kidneys filter blood and produce urine
a. Ureter- tube that carries urine to bladder
b. Bladder- saclike organ that can store up to 1/2 liter of urine
c. Urine released through tube called urethra

14. • The kidneys help to maintain homeostasis.
(3 basic functions)
1. Remove waste products from blood such as those produced from
digestion and cellular respiration
2. Help to maintain electrolyte, pH, and fluid balances in body
3. Release hormones that help keep bones healthy, produce red blood
cells, and regulate blood pressure

15. •Kidneys contain filtering units called nephrons (about 1 million)
1. Filter about 180 liters every day
2. Only about 1 percent excreted as urine

16. Injury and disease can damage kidney functions
1. Can be damaged by infection, diabetes and high blood pressure
2. Only treatment for kidney failure are a kidney transplant or use of dialysis

17. The End