Difference Between Small Intestine And Large Intestine

Small Intestine and the Large intestine are the tubular structures starting from the stomach to the anus. They differ in their functions. The small intestine helps in the digestion and absorption of food whereas the large intestine helps in the absorption of water and electrolytes.

Difference Between Small Intestine and Large Intestine

Features	Small Intestine	Large Intestine
Length	5 to 7m	1.5m
Location	Extends from the stomach to the large intestine	Extends from the small intestine to the anus
Parts	Divided into three parts: Duodenum Jejunum Ileum	Divided into three parts: Caecum Colon Rectum
Diameter	Narrower and longer than the large intestine	Wider and smaller than the small intestine
Specific Structures	Brunner’s glands present in the submucosa of the duodenum Paeyer’s patches present in the mucosa and submucosa of the ileum	Vermiform appendix present in the caecum Symbiotic microbes present for various functions
Key Function	Digestion and absorption of food	Absorption of water and electrolytes
Terminal Connection	Connects to the large intestine through the ileocaecal valve	Connects to the anus through the inner anal sphincter
Additional Absorption Sites	Microvilli, villi, and Plica circularis present for increased surface area absorption	Microvilli, villi, and Plica circularis are absent
Digestive Juice Secretion	Intestinal juice (Succus entericus) released by the crypts of Lieberkuhn	No digestive juices are secreted because no digestion occurs in the large intestine

Small Intestine

• It is a 5 to 7m long tube that extends from the stomach to the large intestine.
• It extends from the pyloric sphincter to the ileocaecal valve.
• It is narrower and longer than the large intestine.
• It is divided into three parts-
  • Duodenum: It is a 0.25m long C-shaped curve and the first part of the small intestine. It is the smallest part of the small intestine. In sub mucosa of duodenum, Brunner’s glands are present. The hepatic-pancreatic opening is also present in the duodenum.
  • Jejunum: It is 2.5m long and is the middle part of the small intestine.
  • Ileum: It is 3.25m long and is the last part of the small intestine. It is highly coiled. The ileocaecal valve is present between the ileum of the small intestine and the caecum of the large intestine. A secondary Lymphoid organ, known as Paeyer’s patches which is a part of MALT is also present in the mucosa and submucosa of the ileum.

Structures present in the complete Small intestine

Microvilli, villi, and Plica circularis help in increasing surface area for the absorption of food. In villi, Lacteal (lymph capillary) is present that absorbs fat-soluble food and vitamins A, D, E, and K. Blood capillary is present that absorbs water-soluble food and vitamins B and C. Crypts of Lieberkuhn are intestinal glands present between two villi. They release intestinal juice ( Succus entericus) that helps in the digestion of fats, proteins, carbohydrates, and nucleic acids.

Large intestine

• It is a 1.5m long tube that extends from the Small intestine to the anus.
• It extends from the ileocaecal valve to the inner anal sphincter. It is wider and smaller than the small intestine.
• It is divided into three parts-

Caecum: ​It is also known as a Blind sac. In Caecum, the Vermiform appendix is present which is a vestigial lymphoid organ. Symbiotic microbes are also present in the caecum helps:

• In the formation of vitamin K and some vitamin B.
• In maintaining local immunity.
• In fermentation of undigested food.

Colon: The Colon is further divided into four regions, namely, ascending colon, transverse colon, descending colon, and sigmoid colon. It is made up of three longitudinal muscles (known as ‘Taenia Coli’) and circular muscles. It is divided into smaller units known as ‘Haustra‘.

Rectum: It stores undigested fermented food.

Small Intestine and Large Intestine

FAQs on Small intestine and Large intestine

Q1: What are the main functions of the small intestine and the large intestine?

Answer:

The main function of the small intestine is to digest and absorb food that passes through it, whereas function of large intestine is to absorb water and electrolytes from undigested food and form faeces.

Q2: How is the small intestine divided?

Answer:

The small intestine is divided into three parts:

1. duodenum
2. jejunum
3. ileum

Q3: How is the Large intestine divided?

Answer:

The large intestine is divided into three parts:

• Caecum
• Colon
• Rectum

Q4: What structures are responsible for increasing the surface area of the small intestine?

Answer:

​M​icrovilli, villi, and Plica circulars are present in the small intestine and help in increasing the surface area for the absorption of food. These structures are absent in the large intestine.