Yesk

1. The
Digestive
System
Prepared by: Cherrie Dee D. Ferrater
8th grade

2. Objectives:
 Identify the different organs that comprise the human digestive system
and its functions.
 Illustrate the different enzymes that are involved in the digestion
process.
 Expound precautionary measure to maintain and keep healthy body.

3. Activity 1: Tummy Puzzle
M W Q S D F F O O D M E T S Y
O T R S A L I V A Z G S Q M K
U B P A N C R E A S A O G A H
T E E T H X M P X S L P D L H
H H J O C K L P F H L H W L Q
S D F N A H A H S Q B A T I G
G H J G M K L A F Q L G W N T
A S W U O R T R Q D A U T T G
F G H E T M J Y R K D S L E P
F S W E S G H N E J D K L S V
L I V E R F B X C D E Q E T Y
G H J K V D F G T A R X A I W
G H J K D S A N U S Q E R N T
H J K S A E W A M X C B F E Q
L A R G E I N T E S T I N E F

4. The Human Digestive Tract
The human digestive tract is around three meters long. It has four
main functions:
1. Ingestion is to take in food through the mouth.
2. Absorption is the process of absorbing food in the form of
nutrients into the blood stream of the body.
3. Assimilation is the process of nutrients being absorbed by each
cell of the body in the form of energy.
4. Excretion is the elimination of materials that cannot be digested.

5. The Human Digestive Tract
The digestive system is composed of different organs. Each
digestive organ can be classified as either an accessory organ or a
part of the alimentary canal.
1. Accessory organs assist in the digestion of food.
• Salivary glands
• Liver
• Gall bladder
• Pancreas

6. The Human Digestive Tract
2. The alimentary canal - contains organs where food passes
through.
• The mouth
• Pharynx
• Esophagus
• Stomach
• Small intestine
• Large intestine
• Rectum.

7. The Oral Cavity
Ingestion is the process in which food is taken into the body
through the mouth for digestion, absorption, and elimination. This
process is accomplished by the mouth or the oral cavity. The
mouth is the first portion of the digestive tract (or alimentary canal).
It receives food and digests the food by chemical and mechanical
means. Physical digestion involves the teeth. Mastication, or
chewing, is performed by the teeth. Food is cut into smaller pieces
so that it can digest easily.

8. The Oral Cavity
Humans have four types of teeth.
1. Incisors, which are used for cutting
2. The cuspids (canines) which are used for tearing
3. The bicuspids (premolars) which are used for crushing,
mashing, and grinding, and
4. The molars- which have broader crowns that are used for
crushing and grinding.

9. FOUR TYPES OF TEETH

10. Initial chemical digestion depends on an accessory organ- the
salivary gland. Chemical digestion involves enzymatic action,
which is accomplished through the saliva. The saliva contains
salivary amylase that helps digest carbohydrates.
Saliva is secreted by the three pairs of salivary glands found in the
oral cavity:

11. 1. Parotid gland- lies in front of the ear; contains saliva near the
second upper molar
2. Sublingual gland- lies under the floor of the mouth; contains
saliva by numerous sublingual ducts
3. Submandibular gland- lies deep in the mouth; contains saliva
on either side of the lingual frenulum (small fold of the tongue)

13. The Pharynx and the Esophagus
The bolus (mass of food) is the end product of the food that has
been chewed, partially digested, and lubricated by the saliva. It is
now ready to be swallowed. The tongue pushes the bolus into the
pharynx, which is the passageway for air, food, and water. Food
is then delivered to the esophagus. A flap called epiglottis closes
the air opening when food is swallowed. It prevents the bolus from
entering the trachea and ensures that the food enters the
esophagus. The bolus in the esophagus keeps moving down by a
rythmic, involuntary action called peristalsis.

14. The Pharynx and the Esophagus

15. The Stomach
The bolus passes through the stomach after leaving the
esophagus. The stomach is a highly muscularized J-shaped sac
that stores food and continues the digestion that began in the
mouth. It can stretch up to nearly twice its original size and can hold
up to two liters of food.
The environment inside the stomach is highly acidic. The lining of
the stomach secretes gastric juice that contains hydrochloric
acid (HCL).

16. The Stomach
Pepsin is the enzyme responsible for digesting proteins.
The environment inside the stomach is acidic and can digest
proteins. Fortunately, the walls of the stomach are protected by
mucus to prevent the stomach from digesting itself. Goblet cells are
responsible for producing the mucus that lines the walls of the
stomach.

17. The Stomach

18. The Small Intestine
The small intestine is named such because of its diameter; yet,
even though its diameter is small, it is the longest part of the
digestive tract. Its is approximately seven meters long.
It is divided into three regions:
• the duodenum
• the jejunum
• the ileum.
It is in the small intestine where digestion is completed. The
completion of chemical digestion depends on three accessory
organs- pancreas, liver and gall bladder.

19. The Small Intestine

20. The Pancreas produces
enzymes that will digest
carbohydrates, protiens, and fats.
The pancreas should also release
alkaline fluids to neutralize
chyme, which is acidic.

21. The liver is another accessory organ. It produces
bile that helps digest fats. Excess bile produced by
the liver is stored in the gall bladder. Bile facilitates
the breakdown of fat globules into smaller droplets for
further digestion by lipases.

23. The Large Intestine
The undigested materials are transported to the
large intestine (or colon) after the absorption of
nutrients is completed. Another function of the large
intestine is to absorb water from the remaining
undigested materials.

24. The large intestine is divided into several segments:
1. ascending colon
2. transverse colon
3. descending colon
4. sigmoid colon- leads to the final portion of the
large intestine called rectum. The rectum is
where the feces are formed. It passes through
the anal canal when the feces are expelled
outside the body.

26. COMMON DIGESTIVE SYSTEM DISORDERS
1. Dental caries - is also known as tooth decay or a
cavity. It is characterized by demineralization and
destruction of the different layers of the tooth
2. Heartburn - is characterized by burning sensation
in the chest. It is caused by the reflux of acid from the
stomach back to the esophagus.

27. COMMON DIGESTIVE SYSTEM DISORDERS
3. Gastric ulcer - is also known as stomach ulcer. A
type of bacterium, Helicobacter pylori, is one of the
most common causes of ulcer
4. Appendicitis – is the inflammation of the
appendix. Appendicitis, based on experiments, is the
result of obstruction of the inside space of the
appendix.
5. Diarrhea - is characterized by having three or
more loose liquid bowel movements per day.