Intestinal Glands: Definition, Function, Diagram, Examples

What Are Intestinal Glands?

The specialised structures in the lining of the intestines are called intestinal glands, otherwise referred to as crypts of Lieberkühn or Brunner's glands. In addition, they are very significant in helping digestion and health maintenance through the secretion of different enzymes, mucus, and other substances that help in the assimilation of nutrients into the system of an animal and offer protection against pathogens.

Anatomy of Intestinal Glands

The intestinal glands hold an important place in the structure of the small and large intestines.

Small Intestine

• The small intestine includes the duodenum, jejunum, and ileum

• Actively engaged in the digestion and assimilation of food.

• It contains the glands of Lieberkuhn and Brunner's glands within the submucosa of the duodenum.

Large Intestine

• Large intestine is comprised of the colon and the rectum

• The major functions include water and electrolyte absorption and the formation of faeces.

• It contains similar glandular structures that secrete mucins that aid in the smooth passage of the intestinal contents.

Location Of Intestinal Glands

The location of intestinal glands is:

• Crypts of Lieberkuhn: In the small intestine, chiefly in its mucous membrane.

• Brunner's Glands: Located in submucosa of duodenum

• Glands in Large Intestine: Similar glands which assist in the secretion of mucus to smoothen the passage of the faeces.

Classification of Intestinal Glands

The intestinal glands are primarily divided concerning their morphology and position.

Crypts Of Lieberkuhn

Structure: Mucosal lining seeding the small intestine with tubular glands.

Cell Types:

• Enterocytes

• Paneth cells

• Goblet cells

• Stem cells

Brunner's Glands

Structure: Compound tubular glands in the submucosa of the duodenum.

Function:

• Secrete alkaline mucus to neutralise stomach acid.

• Protect intestinal mucosa

Functions of Intestinal Glands

The intestinal glands perform various vital roles in the digestive system.

Secretion of Digestive Enzymes

• Breakdown of carbohydrates, proteins and fats.

• Protects the lining of intestines and ensures smooth passage of the contents

Regulation of Intestinal pH

• The stomach acid is neutralised by Brunner's glands to protect the intestinal mucosa.

Absorption Support

• Enterocytes aid nutrient uptake

• Enzymes complete digestion at brush border

Regulation of Intestinal Gland Activity

Intestinal gland activity is controlled in a highly detailed manner to guarantee optimal digestive function.

• Several hormones, such as secretin and cholecystokinin, stimulate the activity of glands.

• The enteric nervous system regulates the secretions of the glands.

• The atomic action in the glands is stimulated by the presence of the chyme.

Role In Health And Disease

The intestinal glands play an important role in maintaining the health of the intestines.

Role in Intestinal Health

• Efficient digestion

• Nutrient absorption

• Mucosal protection

• Immune defence

Diseases Affecting Intestinal Glands

• Crohn's Disease: A chronic inflammatory disorder that emanates from the gastrointestinal tract.

• Ulcerative Colitis: Colon and rectum inflammation with ulcer formation.

• Intestinal Infections: Many pathogenic organisms have the potential to alter the function of the glands.

Effect of Diseases:

• This will result in a decrease in the amount of enzymes produced.

• Poor absorption of nutrients.

• Defective mucosal protective mechanism.

Intestinal Glands NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Anatomy of Intestinal glands

• Functions of Intestinal glands

Practice Questions for NEET

Q1. Identify the precise nature and origin of the enzyme Enterogastrone

1. An enzyme secreted by the gastric mucosa

2. A hormone secreted by the small intestinal mucosa

3. A hormone secreted by the duodenal mucosa

4. A secretory product of an endocrine gland associated with digestion

Correct answer: 3) A hormone secreted by the duodenal mucosa

Explanation:

Enterogastrone is a collective term for various hormones produced by the mucosa of the small intestine, primarily the duodenum. These hormones, such as secretin and cholecystokinin are released in response to the presence of chyme in the small intestine and play a role in regulating digestive processes. The term "enterogastrone" specifically emphasizes its inhibitory effect on gastric motility and acid secretion, helping to slow down the emptying of the stomach and promote efficient digestion and absorption in the small intestine.

Hence, the correct answer is option 3) A hormone secreted by the duodenal mucosa.

Q2. Assertion: The serosa is a smooth membrane made up of a thin layer of cells that release serous fluid and a thin layer of connective tissue.

Reason: Serous fluid is a lubricating fluid that minimises friction caused by muscularis action

1. Assertion and reason are both true, and reason is an accurate account of assertion.

2. Both assertion and reason are accurate, but reason does not adequately explain assertion.

3. The assertion is correct, but the reasoning is incorrect.

4. Both the assertion and reason are incorrect.

Correct answer: 1) Assertion and reason are both true, and reason is an accurate account of assertion.

Explanation:

The serosa is the outermost layer of the small intestine and is composed of a thin layer of cells that secrete serous fluid and a layer of connective tissue. The serous fluid serves as a lubricant that reduces friction caused by the movement of the muscularis layer, which helps the small intestine mix and propel its contents along its length. Therefore, both the assertion and reason are true, and reason accurately explains the assertion.

Hence, the correct answer is option (1) Assertion and reason are both true, and reason is an accurate account of assertion.

Q3. Last section of large intestine is

1. Caecum

2. Colon

3. Rectum

4. Anus

Correct answer: 3) Rectum

Explanation:

The rectum is the final part of the large intestine, situated just before the anus. It plays a vital role in the elimination of waste from the body. The rectum stores formed faeces, which are the byproducts of digestion and absorption until they are ready to be expelled from the body during defecation.

Hence, the correct answer is option 3) Rectum

Also Read:

• MCQs on Small Intestine

• Pancreas Function in Human Body

• Digestion in Ruminants

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