The document describes the parts and functions of the human digestive system. It details each organ of the digestive tract from the mouth through the esophagus, stomach, small intestine, large intestine, and anus. The digestive system breaks down food, absorbs nutrients, and excretes waste. Key organs include the mouth, esophagus, stomach, small intestine, large intestine, liver, gallbladder and pancreas.

1. EDUCATION
IDEA
STRATEGY
TARGET
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Parts and
Function of
Digestive
System

2. III. Innovation /Intervention Strategy
Digestion is the process of
breaking down food into nutrients,
which the body uses for energy,
and cell repair. It consists mainly of
long muscular tube called the
tract. This starts at the mouth,
continues via esophagus and
to the intestines and ends at the
The system also relies on the
pancreas, liver and gall bladder to
digest the food.

3. III. Innovation /Intervention Strategy

4. III. Innovation /Intervention Strategy
Organs of Digestion
 Mouth. It is the first part of the digestive
system composed of teeth and the tongue.
The tongue and the teeth are involved in the
digestion of food in the mouth. There are
different kinds of teeth and performs
different functions in the digestion.
 Incisors. The front teeth with sharp
edges for biting and cutting the food.
 Canine. The pointed teeth which grip
and tear the food.
 Premolars. They crush and grind the
food
 Molars. The flat teeth used for chewing
the food.

5. III. Innovation /Intervention Strategy
 Esophagus. It is a long muscular tube that
connects the pharynx to the throat to the
stomach. The walls of the esophagus is lined
with smooth muscles that contracts
rhythmically to move the food through the
digestive system in the process of peristalsis.
 Stomach. It is a large J-shaped organ at the
end of the esophagus, on the left side of the
body. The capacity of the stomach is 50ml
when empty and can expand up to 2 to 4
liters when full. The end of the stomach has a
sphincter muscle that closes and opens to
allow the flow of from the esophagus to the
stomach.

6. III. Innovation /Intervention Strategy
 Small intestine. It is the long coiled connected
from the stomach. If it is stretched, it is about
seven meters long. It has villi, small like finger
projections that protrude in the lining of the
intestinal wall to increase the absorptive area.
The absorption of the nutrients occurs in the
small intestine with the help of villi.
 There are three parts of the Small
Intestine:
 Duodenum. It is the upper 20 cm.
connected to the stomach
 Jejunum. It is about 2.5 meters long.
 Ileum. It is the longest half coiled through
the abdominal cavity The last 20 or 30
centimeters of the colon are called
rectum.

7. III. Innovation /Intervention Strategy
 Large intestine or colon. It is a large
coiled tube attached to the end of the
small intestine. It is only about 1.5
meters long, which includes the colon,
rectum, and appendix and twice as
wide as the small intestine. The last 20
or 30 centimeters of the colon are
called rectum.

8. III. Innovation /Intervention Strategy
Learning Task 1: Identify the organs of digestion being
described. Select the letter of your answer from the list.
Do this on your answer sheet.
_____ 1. a long coiled connected from the stomach. _____ 2.
a long muscular tube that connects the pharynx to the
throat to the stomach.
_____ 3. a large J-shaped organ at the end of the
esophagus, on the left side of the body.
_____ 4. Is the first part in the digestive system composed
of teeth and the tongue.
_____ 5. a large coiled tube attached to the end of the
small intestine.
A. Mouth B. esophagus C. stomach
D. Large intestine E. small intestine

9. III. Innovation /Intervention Strategy
Learning Task 2: Place the events in the
correct order. Number each sentence 1-5.
___ 1. Food ends up in the small intestine.
___ 2. Food is chewed up.
___ 3. Food is in the large intestine.
___ 4. Food travels through the esophagus.
___ 5. Food waste leaves the body.

10. III. Innovation /Intervention Strategy
The digestive system is made up of a continuous tube
called the digestive tract or gastrointestinal tract,
extending from the mouth to the anus, and some solid
organs, such as the liver, gallbladder, and pancreas.
 Mouth: Digestion begins in the mouth itself. The food
is broken down into smaller pieces using the teeth.
Chewing makes the job easier for the digestive juices
in the stomach. Saliva formed in the mouth contains
the enzyme called ptyalin, which breaks down the
food. The tongue then rolls the masticated food into a
ball, known as the bolus and pushes it to the posterior
end of the mouth, and into the pharynx.
 Pharynx: The pharynx is a five-inch long tube that
serves as a common passage for both food and air.
The pharynx allows the bolus from the mouth, to enter
the esophagus, which is the next part of the digestive
system.

11. III. Innovation /Intervention Strategy
 Esophagus: The esophagus is a ten-inch long tube-like
passage that connects the pharynx with the upper end of
the stomach. The bolus from the mouth passes through the
esophagus to reach the stomach. The upper and lower ends
of the esophagus have sphincter muscles that prevent
leaking of food from the stomach to the esophagus and the
mouth. While swallowing, these muscles relax and allow
passage of food and liquids.
 Stomach: The stomach is a sac-like structure and happens to
be the most dilated part of the digestive system. The
primary function of the stomach is to collect and break
down food. The stomach secretes gastric juice, which digests
food like meat, eggs, and milk. However, gastric juice does
not digest starch, sugars, and fats. It also secretes
hydrochloric acid and pepsin enzymes. While certain types
of food remain in the stomach for two to five hours after
ingestion, liquids and other small particles get emptied fast.
This partly digested food in the stomach is called chime,
which is then passed to the small intestine.

12. III. Innovation /Intervention Strategy
 Small Intestine: Stretching from the stomach to the
large intestine is the 20-feet-long small intestine,
which is coiled in the central portion of the
abdominal cavity. It is in this small intestine that the
most extensive part of digestion occurs. The main
functions of the small intestine include digestion and
absorption of nutrients. The pancreas is a gland
organ that is located behind the stomach, and is
connected to the duodenum – the first part of the
small intestine. The pancreas secretes hormones and
digestive enzymes which help in digestion of food.
Carbohydrates, lipids and proteins are broken down
and digested. Moreover, the salts secreted by the liver
and gallbladder work in coordination with pancreatic
lipase and digest lipids.

13. III. Innovation /Intervention Strategy
 Large Intestine: The large intestine is a five-feet long
tube, which is subdivided into different parts such as
the cecum, colon, and rectum. The function of the
large intestine is to absorb water and mineral salts
from the digested food received from the small
intestine. Moreover, the friendly bacteria present in
the colon produces vitamin K, which is needed for the
body’s blood clotting process. The waste material or
feces is stored in the sigmoid colon, from where it is
passed to the rectum. It is from the rectum that the
feces is excreted out of the body via the anus.
 Anus: The anus or anal opening is the last part of the
digestive system, through which feces is eliminated
from the body.

14. III. Innovation /Intervention Strategy
Learning Task 3: Choose the letter of the correct
answer. Do this on your answer sheet.
1. Which moves the food from the esophagus to
the stomach?
a. Swallowing c. peristalsis
b. fluid d. digestion
2. It is the organ where digestion starts
a. Mouth c. stomach
b. Small intestine d. large intestine
3. Which organ takes nutrients from your food
and puts it in your bloodstream?
a. Stomach c. small intestine
b. esophagus d. large intestine

15. III. Innovation /Intervention Strategy
4. In which part of the digestive system are
proteins digested completely?
a. Stomach c. small intestine
b. Large intestine d. esophagus
5. In which part of the digestion system does
digestion end?
a. Mouth c. stomach
b. Small intestine d. large intestine

16. III. Innovation /Intervention Strategy

17. III. Innovation /Intervention Strategy
Learning Task 1: Identify the organs of digestion being
described. Select the letter of your answer from the list.
Do this on your answer sheet.
_____ 1. a long coiled connected from the stomach. _____ 2.
a long muscular tube that connects the pharynx to the
throat to the stomach.
_____ 3. a large J-shaped organ at the end of the
esophagus, on the left side of the body.
_____ 4. Is the first part in the digestive system composed
of teeth and the tongue.
_____ 5. a large coiled tube attached to the end of the
small intestine.
A. Mouth B. esophagus C. stomach
D. Large intestine E. small intestine
E
B
C
A
D

18. III. Innovation /Intervention Strategy
Learning Task 2: Place the events in the
correct order. Number each sentence 1-5.
___ 1. Food ends up in the small intestine.
___ 2. Food is chewed up.
___ 3. Food is in the large intestine.
___ 4. Food travels through the esophagus.
___ 5. Food waste leaves the body.
1
2
3
4
5

19. III. Innovation /Intervention Strategy
Learning Task 3: Choose the letter of the correct
answer. Do this on your answer sheet.
1. Which moves the food from the esophagus to
the stomach?
a. Swallowing c. peristalsis
b. fluid d. digestion
2. It is the organ where digestion starts
a. Mouth c. stomach
b. Small intestine d. large intestine
3. Which organ takes nutrients from your food
and puts it in your bloodstream?
a. Stomach c. small intestine
b. esophagus d. large intestine

20. III. Innovation /Intervention Strategy
4. In which part of the digestive system are
proteins digested completely?
a. Stomach c. small intestine
b. Large intestine d. esophagus
5. In which part of the digestion system does
digestion end?
a. Mouth c. stomach
b. Small intestine d. large intestine