1. The Digestive System

2. Nutrition
 Nutrition is the study of how food affects
the function of living organisms.
 Food contains nutrients.
 If cells don’t have nutrients, they don’t
function correctly.
 Poor diet = poor cells.
 There are six general categories of
nutrients.

3. Six Nutrient Categories
Energy Regulatory
Suppliers Nutrients
 Carbohydrates  Water
 Lipids  Vitamins
 Proteins  Minerals

4. 2 Factors leading to Nutritional
Problems
 1) too little physical activity
(sedentary lifestyle)
 2) Over consumption of food
 Leads to obesity

5. The Digestive System
 System is responsible for breaking down food
so that it can be absorbed by the
bloodstream.
 The “alimentary canal” is the pathway which
food travels through the digestive system.

6. The Alimentary Canal
 Mouth
 Esophagus 26 ft long!!!!!!!
 Stomach
 Small intestine
 Large intestine
 Rectum
* The liver, pancreas, and gallbladder are parts of
the digestive system but are not parts of the
alimentary canal.

8. The Mouth
 Chemical (saliva) and mechanical
(chewing) digestion occur in the mouth.
 Salivary glands produce saliva.
 Saliva lubricates food.
 Saliva contains enzyme amylase (starch
digestion).

9. Esophagus 9.8 in
 Muscular tube.
 Leads from back of throat
(pharynx) to the stomach.
 Opening to trachea (tube)
and esophagus (soft) are
right next to each other.
 Epiglottis prevents food
from going down the wrong
tube.
 Muscular contractions
(peristalsis) pushes food
down the esophagus.

10. Stomach 4 hours
 Responsible for protein digestion.
 Chemical and mechanical digestion.
 Hydrochloric acid and pepsin
(enzyme) break down proteins into
amino acids. (pH 1.5-2.5)
 Stomach lining contains mucus.
 Mucus protects stomach from acid.
 Ulcers
 Sphincter muscles (cardiac and
pyloric) control what enters and
leaves the stomach.

11. Small Intestine
 20 ft. long.
 The first part of the small
intestine is called the
“duodenum.”
 Remaining carbo’s and
proteins are broken down.
 All lipids are digested in
S.I.
 Gall bladder. (stores bile
from the liver & delivers to
the S.I.)
 Duodenum connects to
liver and pancreas.

12. Liver and Pancreas
Secrete Digestive Enzymes
LIVER JOBS PANCREAS JOBS
 Detoxifies drugs and  Regulates blood
alcohol sugar.
 Secretes bile into  Releases digestive
duodenum. enzymes into
 Bile breaks down duodenum.
lipids.  Neutralizes stomach
 Bile is stored in the acid before it enters
gall bladder. S.I.

13. Small Intestine (cont.)
 After all nutrients are
digested from food,
they are absorbed into
the blood.
 S.I. contains lots of
capillaries.
 Mesentary.

14. Large Intestine
 All proteins, carbos, and
lipids have been removed
from food by the time it gets
here.
 Water in food is absorbed
into the blood.
 Vitamins are absorbed into
the blood.
 Whatever food is left is
“fecal” matter and passes
out the rectum and anus.
 Feces is undigested food.

15. Excretory System
 Kidney
 Clean the blood
 Vital role in maintaining homeostasis
 Removes waste
 Regulate amount of water in blood
 Nephrons- blood cleaning units
 Forms urine
 Urine contains nitrogenous waste
products, excess amounts of water and
solutes.
 ~1 Liter of urine produced each day.

16. Reabsorption
 Returns important substances to the
blood.
 Second process of urine formation

17. Kidney Disorders & Treatment
 ~ 13 million people suffer form kidney
disorders in the US.
 Kidney stones-
 Uric or oxalic acid, calcium salts, etc. collect
outside of kidneys
 Hemodialysis-
 Filtering of blood.
 Receive 2x’s a week