The document discusses the digestive system and nutrition. It explains that the digestive system breaks down food so nutrients can be absorbed. The alimentary canal is where digestion occurs, including the mouth, esophagus, stomach, small intestine, large intestine, and rectum. Various organs help digestion, like the liver, pancreas, and gallbladder. Carbohydrates, proteins, lipids, vitamins, minerals, and water are the six categories of nutrients obtained from food.

1. The Digestive System
Presented By:
Mrs. Nelson

2. Nutrition
 Nutrition is the study of how food affects
the function of living organisms.
 Food contains nutrients.
 Nutrients provide the energy and materials
organisms need.
 If organism’s cells are not provided with
nutrients, the cells will not function
properly.
 Poor diet = poor cells

3. Six Categories of Nutrients
Energy Suppliers
 Carbohydrates
 Lipids
 Proteins
Non-Energy Suppliers
 Water
 Vitamins
 Minerals

4. Carbohydrates
 Glucose is main source of carbohydrates
for animals.
 Glucose is easily converted to ATP.
 Glucose is found in fruits, vegetables,
grains, and dairy foods.
 Many foods contain cellulose also known
as “fiber.” Important for helping push food
through the digestive tract.
 Energy from food is measured in
“calories.”

5. Lipids
 Provide twice as much energy as carbohydrates.
 Important for…
1) Making cell membranes
2) Hormone production
3) Myelin production
4) Protect organs and insulate body
 Take long time to digest.
 Too much fat in diet= excess energy = fat
deposits.
 Saturated fats (solid, contain single bonds)
contain LDL cholesterol and build up on arteries.

6. Proteins
 Proteins made of amino acids.
 20 different amino acids.
 Body can make 12/20 amino acids.
 The other eight must come from food are
called “essential amino acids.”
 Proteins are materials needed for…
1) growth and repair.
2) skin and muscles.
3) regulatory (enzymes- insulin) and transport
functions (hemoglobin– RBC).

7. Water
 Most important nutrient.
 Lubricates areas of body (blood, lymph,
plasma, etc.)
 Coolant for body.
 Solvent for digestion.
 Provides fluid environment for cells.
 Body needs intake 1L of water a day.

8. Minerals
 Inorganic (not made by living things).
 Plants absorb minerals.
 Animals eat plants to get minerals.
 Minerals are only needed in trace amounts
by the body.
 Iron (hemoglobin RBC)
 Calcium (bones and teeth)
 Sodium/Potassium (nerve and muscle
function)
 Magnesium/Zinc/Iodine

9. Vitamins
 Organic (made by living things).
 Help regulate body processes.
 Most obtained from food.
 Vitamin K- made by bacteria in digestive tract.
 Vitamin D- synthesized by skin cells when
exposed to sunlight.
 2 types vitamins…
1) Fat soluble- can be stored in fatty
tissues for future use (A, D, E, K)
2) Water soluble- dissolve in water and can
not be stored by body (C, B)

10. Importance of Various Vitamins
 A, C, D, E, K, Folic Acid, B12
Helps RBC mature

11. The Digestive System
 System is responsible for breaking down food
so that nutrients can be absorbed by the
bloodstream.
 The “alimentary canal” is the pathway which
food travels while it is digested.

12. The Alimentary Canal
 Mouth
 Esophagus
 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.

14. The Mouth
 Chemical digestion –saliva contains
enzyme amylase that digests
carbohydrates (starches)
 Mechanical digestion- chewing

15. Esophagus
 Tube from back throat
to stomach.
 Trachea (lungs) and
esophagus are next to
each other.
 Epiglottis prevents food
from going down the
wrong tube.
 Peristalsis- muscular
contractions pushes
food down esophagus.

16. Stomach
 Chemical/mechanical
digestion.
 Hydrochloric acid and
pepsin (enzyme) break
down proteins to
amino acids.
 Stomach lining contains
mucus.
 Mucus protects stomach
from acid (ulcers).
 Sphincter muscles (cardiac
and pyloric) control what
enters and leaves the
stomach (heartburn).

17. Small Intestine
 20 ft.
 Remaining carbohydrates
and proteins are broken
down.
 All lipids are digested here.
 Connected to liver and
pancreas.

18. Liver and Pancreas
LIVER JOBS
 Makes and secretes
bile (needed digest
lipids).
 Bile is stored in the
gall bladder.
 Detoxifies drugs and
alcohol.
PANCREAS JOBS
 Regulates blood
sugar.
 Secretes digestive
enzymes into small
intestine.
 Neutralizes stomach
acid as it enters the
small intestine
(bicarbonate).

19. Small Intestine (cont.)
 After all nutrients are
digested, they are
absorbed. This is the
major job of this
organ.
 S.I. contains lots of
capillaries.
 Mesentary.

20. Large Intestine
 All proteins,
carbohydrates, and
lipids have been
removed from food by
the time it gets here.
 Water is absorbed
(diarrhea).
 Vitamins are absorbed.
 Feces is undigested
food passes out rectum
and anus.