The document discusses the nutrition function and digestive system. It describes how the digestive system, along with other body systems, takes in nutrients from food, absorbs and assimilates them. It then discusses the specific organs involved in digestion, including the mouth, esophagus, stomach, small intestine, large intestine, liver, gallbladder and pancreas. It explains the key roles and processes of each organ, such as ingestion, digestion, absorption and egestion.

1. THE NUTRITION FUNCTION I.
The digestive system.

2. The nutrition function.
 Taking in of nutrients (found in food) which are
organic substances and mineral ions, containing
raw materials or energy for growth and tissue
repair, absorbing and assimilating them.
 In multicellular organisms, several systems take
part in this function.
 Digestive system.
 Respiratory system.
 Circulatory system.
 Excretory system.
Intimately interlinked.
Endocrine and nervous
system also participate.

3. Digestive System Processes.
 Ingestion : Intake of food into the body through
mouth.
 Digestion: The process of break-down of
large, insoluble food molecules into small, water
soluble molecules using mechanical and chemical
processes.
 Absorption : The process of passing digested food
molecules across the wall of the intestine into the
blood or lymph.
 Assimilation : The movement of digested food
molecules into the cells of the body where they are
used, becoming part of the cells.
 Egestion : Passing out of undigested food, in
the form of faeces, through the anus.

4. Digestion
Mechanical
Chew
Tear
Grind
Mash
Mix
Chemical
Carbohydrates
Lipids
Protein
s
(physical)
Enzymatic reactions to
improve digestion of

5. Digestive System Organization
• Gastrointestinal
tract.
• Accessory glands.

6. Digestive System Organization
• Gastrointestinal
tract.
– Direct link/path between
organs, 8m.
– Shape varies.
– Secrete mucus (ˈmjuːkəs) or
digestive juices.
– Structures
• Mouth
• Pharynx
• Esophagus
• Stomach
• Small intestine
• Large Intestine
• Rectum

7. Digestive System Organization.
 Gastrointestinal
tract.
 Accessory organs.
 Not part of the path of
food, but play a critical
role.
 Include:
 Salivary glands,
 liver, gall bladder, and
 pancreas

10. Mouth
 Epiglottis is a
flap-like
structure at the
back of the
throat that
closes over the
trachea
preventing the
bolus from
 CHEWING: Teeth mechanically break down food into
small pieces.
 SALIVATION: Tongue mixes food with saliva (contains
amylase (ˈæmɪleɪz), which helps break down starch).
 SWALLOWING: the tongue push the bolus towards the
pharynx.

11.  Saliva (səˈlaɪvə) is a
watery liquid released
by salivary glands.
 Starts digestion of
starch molecules:
AMYLASE
(ˈæmɪˌleɪz).
 Destroys some
bacteria:
LYSOZYME
(ˈlaɪsəˌzaɪm).
 Eases the bolus into

14. PHARYNX
 It is a common passageway for air and food.
It participates in swallowing
(ˈpælɪt)
(ɛpɪˈɡlɒtɪs)
(ɪˈsɑfəgəs)

15. Esophagus
 Approximately 20-
25cm long
 Functions include:
1.Secretes mucus
2.Moves food from the
throat to the stomach
using muscle
movement called
peristalsis
(pɛrɪˈstælsɪs)
 If acid from the
stomach gets in here
that’s heartburn
(cardia at the entering
of the stomach stops

17. Stomach
 J-shaped muscular bag that stores the food
you eat, and digests it.
 Mixes food with digestive juices that
contain enzymes to break down proteins
(pepsine) and lipids.
 HYDROCHLORIC ACID in the stomach
kills bacteria, and supports enzyme’s work.
 It absorbs water, alcohol and some drugs.
 Food in the stomach is called chyme
(kaɪm), once it has mixed with gastric
juices.
The stomach takes around 4 hours to do it’s
job on the food, depending on what kinds
of food are digested.

18. cardia
paɪˈlɔːrəs
ˈkɑːdɪə
djuːəʊˈdiːnəm

19. Small Intestine
 Small intestines are roughly 7
meters long, finishing in the
ileocecal valve.
 Intestine walls have finger-like
projections called villi, to increase
surface area.
 The villi are covered in microvilli
which further increases surface

21. Small Intestine
 Nutrients from the food pass into the bloodstream through
the small intestine walls.
 Establishes an optimal pH for
enzymes.
 Secretes digestive enzymes.
 Absorbs:
 80% ingested water.
 Vitamins.
 Minerals.
 Carbohydrates.
 Proteins.
 Lipids.

22.  When the chyme mixes with intestinal
juices, and secretions from liver and
pancreas, it transforms into chyle (kaɪl).
 The first part of
intestine
(duodenum)
receives
following
secretions.
 Pancreatic juice
from pancreas.
 Bile juice from
liver.

23. Liver
 Directly affects digestion by
producing bile
 Bile helps digest fat.
• Filters out toxins and waste including
drugs and alcohol.
 Bile does not contains any enzymes.
 Bile contains bile salts which acts on
fats.
 Bile salts break fats up into smaller fat
droplets which can be more easily
digested by lipase.23

24. Gallbladder
 Stores bile from the
liver, releases it into
the small intestine.
 Bile is realeased
through the ampulla of
Vader.
 Fatty diets can cause
gallstones.

25. Pancreas
 Produces digestive
enzymes to digest
fats, carbohydrates
and proteins.
 Regulates blood sugar
by producing insulin, a
hormone.
 Pancreatic juice also
neutralizes the acid
liquid from the
stomach.

26.  After digestion, simpler molecules are obtained:
 Monosaccharides.
 Glycerol and fatty acids.
 Amino acids.
 Those nutrients are absorbed through the small
intestine inner layer. Capillaries collect them.

27. Large Intestine
 About 1’5 m long.
 Accepts what small intestines
don’t absorb.
 Functions
 Bacterial digestion
 Ferment carbohydrates
 Protein breakdown
Absorbs more water.
 Concentrates wastes.

28. Large Intestine
 Portions of the large intestine,
 ascending,
 transverse,
 descending,
 sigmoid, and
 Rectum.
The rectum is the short term storage which holds
feces before it is expelled).

29. https://www.youtube.com/watch?v=8YXKklSxW30

30. Write the name of each colored organ:
 Green:
 Red:
 Pink:
 Brown:
 Purple:
 Green:
 Yellow:

31. How’d you do?
 Green: Esophagus
 Red: Stomach
 Pink: Small Intestine
 Brown: Large Intestine
 Purple: Liver
 Green: Gall Bladder
 Yellow: Pancreas

32. References and Links
 Inner body: http://www.innerbody.com/
 Your Digestive System and How It Works
 Digestive system diagram comes from this site
 The Real Deal on the Digestive System
 Pancreas: Introduction and Index
 Your Gross and Cool Body - Digestive System