The document summarizes the anatomy and physiology of the large and small intestines. It describes the main parts and functions of the large intestine, including the caecum, colon, rectum, and anal canal. It also discusses disorders that can affect the large intestine. For the small intestine, it outlines the duodenum, jejunum, and ileum, and their functions in digesting and absorbing nutrients. The document provides references for more information on the intestines.

2. Subject: Physiology
Presented by: Group B
Presented to: Sir Yasir Ali

3. Large intestine and its parts
Small intestine and its parts
Topics:

4. Large intestine
The large intestine is the last part of the gastrointestinal (GI) tract, the
long, tube-like organ that is connected to the small intestine at one
end and the anus at the other.
 The large intestine is about 1.5 meters long.

5. Location:
The large intestine is located in our lower abdominal cavity from
our waist down. It surrounds the small intestine in a sort of a
square question mark shape, with the tail of the question mark
ending at the anal canal.

6. Functions:
The large intestine has 3 primary functions:
Absorbing water and electrolytes,
Producing and absorbing vitamins,
Forming and propelling feces toward the rectum for
elimination.

7. Parts of large intestine:
The large intestine has four parts:
 Caecum
 Colon
 Rectum
 Anal canal

8. Caecum:
This is the first part of the large intestine. It is about 8 to 9 cm
long. The small intestine feeds into the caecum through a small
channel in the side of it (the ileocaecal valve), so the end of the
caecum is actually closed like a pouch. This pouch, the first 6
inches of the colon, is also the widest portion of the large intestine.
This is the reservoir where food from the small intestine arrives in
the large intestine. When the caecum is full, it triggers the muscle
movements of the colon to begin.

10. Appendix:
From the end of caecum
there arises a finger like
process called appendix. The
appendix some time gets
inflamed due to entrapping
and then purification of food
causing appendicitis, which
has to be removed surgically
in many instances.

11. COLON
ASCENDING
COLON
TRANSVERSE
COLON
DESCENDING
COLON
SIGMOID
COLON
 Passes upwards
from caecum to
liver.
 It curves acutely to
the left at the
hepatic flexure to
become the
transverse colon.
 It extends across
the abdominal
cavity to the area of
spleen.
 It forms splenic
flexure and become
descending colon.
 It extend to the left
side of abdominal
cavity then curves
the midline.
 It forms sigmoid
colon at iliac crest.
 It forms S
shaped curve in
the pelvic cavity
 It continues
downward to
become rectum.

12. Function of Colon:
As food proceeds to the ascending colon, it travels upward and
eventually sideways across the transverse. Any remaining water
and electrolytes are absorbed in the ascending and transverse
colon so that the food waste that arrives in the descending colon is
mostly solid.
Mucous:
The colon secretes mucus to bind and lubricate the food waste to
help it pass through smoothly as it is dehydrated. Like the small
intestine, the large intestine churns the food against its mucous
lining and also moves it forward through periodic muscle
contractions.

14. Rectum:
It is about 13 cm long. By the time the sigmoid colon delivers the
food waste to the rectum, it resembles the faeces. The faeces now
consist of indigestible matter and dead cells along with small
amounts of mucus and water. When faeces enters the rectum, it
triggers the urge to defecate. This is the natural continuation of the
mass muscle movements of the colon
Anal canal:
It’s length is about 3.8cm.The anus is the canal where faeces will
travel through to leave body. Two sphincter muscles control the
anus
 The internal sphincter opens automatically to let waste
through.
 The outer sphincter is the one control to let waste out when
you’re ready

15. Disorders of large intestine:
Functional disorders, structural disorders, infections and
irritations can affect the large intestine, including the colon,
rectum and anus. Some of these conditions include:
Appendicitis
Chronic diarrhea
Colon cancer
Intestinal cancer

16. Small intestine:
It is part of gastrointestinal tract, extending between the pyloric
sphincter of stomach and ileocecal valve which opens into large
intestine.
It is called small intestine because of its small diameter.
Its length is about 6m.

18. Parts:
• Proximal part known as duodenum.
• Middle part known as jejunum.
• Distal part known as ileum.

19. Duodenum:
This is about 25cm long and curves around head of pancreas.
Secretion from the gall bladder and pancreas merge in a common
structure The Hepto Pancreatic Empulla and enter the duodenum
at the duodenal papilla. It is guarded by a ring of smooth muscles
known as Hepto Pancreatic Spinchter.

20. Jejunum:
Its length is about 1m.
It is characterized by many blood
vessels, which give it a deep red
color.
Ileum:
It is about 3m long and ends at
ileoceacal valve, which control
flow of material from the ileum to
the caecum and prevent back flow.

21. Functions:
1. Mechanical functions:
Small intestine helps in mixing of chyme with digestive juices
like succus and bile etc.
2. Secretory function:
It secretes entrokinase and gastrointestinal hormones.
3. Hormonal function:
small intestine secretes many G.I hormones such as secretin.
Gastron, and cholecystokinin-pancreozymin.

22. 4. Digestive function:
 It systematically breaks food down
 Absorbs nutrients,
 Extract water
 Moves food along the G.I tract
5. Absorptive function:
Presence of villi and microvilli in small intestinal mucosa
increase the surface area of mucosa. This facilitate the
absorptive function of intestine, digestive products of food stuff,
proteins, carbohydrates and other nutritive substance such as
vitamins are absorbed in small intestine.

23. Disorders in small
intestine:
• Celiac disease.
• Crohn's disease.
• Infections.
• Intestinal cancer.
• Intestinal obstruction.
• Irritable bowel syndrome.
• Ulcers, such as peptic ulcer.

24.  https://my.clevelandclinic.org/health/body/22134-
colon-large-intestine
 https://my.clevelandclinic.org/health/body/22135-
small-intestine
REFERENCES: