Intestinal Glands: Definition, Function, Diagram, Examples

Edited By Irshad Anwar | Updated on Jul 02, 2025 06:26 PM IST

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.

This Story also Contains

What Are Intestinal Glands?
Anatomy Of Intestinal Glands
Location Of Intestinal Glands
Classification Of Intestinal Glands
Functions Of Intestinal Glands
Role In Health And Disease
Effect Of Diseases On The Function Of Glands:
The Video Recommended For Intestinal Glands:

Intestinal Glands: Definition, Function, Diagram, Examples

Anatomy Of Intestinal Glands

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

The small intestine, namely the duodenum, jejunum, and ileum, is 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.
The major functions of the large intestine, which is comprised of the colon and the rectum, include water and electrolyte absorption and the formation of faeces.
Additionally, it contains rather similar glandular structures as of the small intestine to secrete mucins that aid in the smooth passage of the intestinal contents.

Location Of Intestinal Glands

Crypts of Lieberkuhn in the small intestine: In the small intestine, chiefly in its mucous membrane.
Brunner's Glands in the duodenum: In duodenal submucosa.
Other Associated Glands in Large Intestine: There are 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

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Brunner's Glands

Structure: Compound tubular glands in the submucosa of the duodenum.
Function: Secrete alkaline mucus to neutralise stomach acid.

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.
Enzymes and enterocytes help in absorption.
Protection Against Pathogens

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 Of The Intestinal Glands In Maintaining Intestinal Health:

Digestion, absorption of nutrients, and immunity

Common Pathologies Affecting The 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 On The Function Of Glands:

This will result in a decrease in the amount of enzymes produced, poor absorption of nutrients, and defective mucosal protective mechanism.

Conclusion

Intestinal glands are integral to the proper functioning of the digestive system; their functions involve efficient digestion, proper absorption of nutrients, and protection from pathogens. Therefore, study at this level concerning structure, functions, and their regulations will help attain gastrointestinal health. Further studies carried out on these glands can make the management and treatment of the associated diseases much easier.

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Frequently Asked Questions (FAQs)

1. What are intestinal glands?

Intestinal glands refer to those specialised structures that exist within the intestines and are responsible for secreting enzymes, mucus, and other associated substances for digestion and protection.

2. What is the function of the Crypts of Lieberkuhn?

Secrete digestive enzymes and other cell types that will then help in the absorption of nutrients and provide protection to the lining of the intestines.

3. How do Brunner's glands work?

Brunner's glands secrete alkaline mucus to help neutralise stomach acid; hence, saving the duodenum from its acidity and in turn facilitating digestion.

4. What is the cell makeup of the intestinal glands?

Intestinal glands have enterocytes, Paneth cells, goblet cells, and stem cells. Each cell portion takes part in maintaining various areas of well-being as it pertains to digestion.

5. How are disorders of the intestinal glands treated?

The line of major treatment usually includes antibiotic and anti-inflammatory drugs a change of diet; and in advanced cases, surgery.

6. What is the significance of the crypt-villus axis in the small intestine?

The crypt-villus axis refers to the structural and functional unit of the small intestine, where intestinal glands (crypts) are located at the base of finger-like projections called villi. This arrangement maximizes the surface area for absorption while allowing for the continuous renewal of the epithelium from the base of the crypts.

7. What is the significance of the intestinal gland lumen?

The intestinal gland lumen is the central cavity of the gland where secretions are released. It plays a crucial role in collecting and concentrating various secretions before they are released into the main intestinal lumen, allowing for efficient delivery of enzymes, mucus, and other substances to aid in digestion and protection.

8. What is the significance of the "crypt cycle" in intestinal gland function?

The "crypt cycle" refers to the continuous process of cell renewal in intestinal glands. Stem cells at the base of the gland divide to produce daughter cells, which then migrate up the sides of the gland while differentiating into various cell types. This cycle ensures the constant renewal of the intestinal epithelium, maintaining its functional integrity.

9. What is the role of intestinal glands in nutrient absorption?

Intestinal glands increase the surface area of the intestinal lining, providing more space for nutrient absorption. The absorptive cells lining the glands contain various transporters and enzymes that facilitate the uptake of nutrients from the intestinal lumen into the bloodstream.

10. How do intestinal glands contribute to the production of digestive enzymes?

While most digestive enzymes are produced by the pancreas, intestinal glands also contribute by producing and secreting certain enzymes, such as peptidases and disaccharidases. These enzymes help in the final stages of digestion, breaking down partially digested food molecules into their simplest forms for absorption.

11. How do intestinal glands differ between the small and large intestines?

In the small intestine, intestinal glands are more numerous and contain a variety of cell types, including absorptive cells, goblet cells, Paneth cells, and enteroendocrine cells. In the large intestine, the glands are deeper and contain mainly absorptive cells and goblet cells, with fewer specialized cell types.

12. What is the role of intestinal glands in the production of intrinsic factor?

While intrinsic factor is primarily produced by the stomach, some research suggests that certain cells in the intestinal glands may also produce small amounts of this protein. Intrinsic factor is crucial for the absorption of vitamin B12 in the small intestine, highlighting the potential contribution of intestinal glands to this important process.

13. What is the role of intestinal glands in the production of gut hormones?

Intestinal glands contain enteroendocrine cells that produce various gut hormones, such as cholecystokinin, glucagon-like peptide-1, and peptide YY. These hormones play crucial roles in regulating appetite, digestion, and metabolism by signaling to other organs and tissues in the body.

14. How do intestinal glands contribute to the body's defense against pathogens?

Intestinal glands contribute to pathogen defense through multiple mechanisms: secretion of antimicrobial peptides by Paneth cells, production of protective mucus by goblet cells, and interaction with the gut-associated lymphoid tissue to initiate immune responses against potential threats.

15. What is the significance of the "intestinal gland-microbiome axis" in gut health?

The "intestinal gland-microbiome axis" refers to the bidirectional interaction between intestinal glands and the gut microbiome. Gland secretions influence microbial populations, while microbial metabolites can affect gland function. This interplay is crucial for maintaining gut homeostasis, nutrient metabolism, and immune function.

16. How do intestinal glands adapt to changes in diet or nutrient availability?

Intestinal glands can adapt to changes in diet or nutrient availability by altering their secretion patterns and enzyme production. For example, increased consumption of certain nutrients can lead to upregulation of specific transporters or enzymes in the gland cells, enhancing their ability to process and absorb those nutrients.

17. What is the relationship between intestinal glands and the enteric nervous system?

The enteric nervous system, a network of neurons in the gut, interacts closely with intestinal glands. It regulates gland secretion and motility through various neurotransmitters and signaling molecules, coordinating digestive processes in response to food intake and other stimuli.

18. What is the significance of the intestinal stem cell niche in gland function?

The intestinal stem cell niche, located at the base of the intestinal glands, is crucial for maintaining gland function. It provides the necessary environment for stem cells to divide and differentiate into various cell types, ensuring the continuous renewal of the intestinal epithelium and the proper functioning of the glands.

19. How do intestinal glands regulate their secretory activity?

Intestinal glands regulate their secretory activity through various mechanisms, including hormonal signals, neural stimulation from the enteric nervous system, and local factors such as changes in pH or nutrient concentrations. This allows for dynamic adjustment of gland function in response to changing digestive needs.

20. What is the role of intestinal glands in maintaining the gut-brain axis?

Intestinal glands, through their production of various hormones and interaction with the enteric nervous system, play a significant role in the gut-brain axis. They contribute to signaling pathways that communicate information about gut status to the brain, influencing mood, appetite, and overall well-being.

21. What is the primary function of intestinal glands?

The primary function of intestinal glands is to secrete various substances that aid in digestion and absorption of nutrients. These include enzymes, mucus, and other fluids that help break down food, protect the intestinal lining, and facilitate the absorption of nutrients.

22. What is the role of goblet cells in intestinal glands?

Goblet cells in intestinal glands produce and secrete mucus, which forms a protective layer over the intestinal epithelium. This mucus layer helps lubricate the intestinal contents, protects the lining from mechanical and chemical damage, and provides a habitat for beneficial gut bacteria.

23. What are enteroendocrine cells, and what is their function in intestinal glands?

Enteroendocrine cells are specialized cells found in intestinal glands that secrete various hormones, such as cholecystokinin, secretin, and gastrin. These hormones help regulate digestion, appetite, and other gastrointestinal functions by signaling to other organs and tissues.

24. How do intestinal glands contribute to the renewal of the intestinal epithelium?

The base of intestinal glands contains stem cells that continuously divide and differentiate into various cell types. This process allows for the constant renewal of the intestinal epithelium, replacing damaged or worn-out cells and maintaining the integrity of the intestinal lining.

25. How do intestinal glands aid in water absorption?

Intestinal glands, especially in the large intestine, play a crucial role in water absorption. The absorptive cells lining the glands actively transport water from the intestinal lumen into the bloodstream, helping to maintain fluid balance in the body.

26. What are intestinal glands and where are they located?

Intestinal glands, also known as crypts of Lieberkühn, are tubular structures found in the lining of the small and large intestines. They extend from the surface of the intestinal mucosa down to the muscularis mucosae, forming a network of secretory units that play a crucial role in digestion and absorption.

27. What is the significance of the "crypt base columnar cells" in intestinal glands?

Crypt base columnar cells are a type of intestinal stem cell located at the bottom of intestinal glands. These cells are crucial for the continuous renewal of the intestinal epithelium, dividing to produce all the different cell types found in the glands and on the villi, thus maintaining the structure and function of the intestinal lining.

28. What is the role of intestinal glands in the production of antimicrobial peptides?

Intestinal glands, particularly through Paneth cells in the small intestine, produce various antimicrobial peptides such as defensins and lysozyme. These peptides help regulate the gut microbiome, protect against pathogens, and maintain the overall health of the intestinal environment.

29. How do Paneth cells in intestinal glands help maintain gut homeostasis?

Paneth cells, found at the base of small intestinal glands, secrete antimicrobial peptides and other factors that help regulate the gut microbiome. By controlling bacterial populations, they maintain a balance between beneficial and harmful microorganisms, contributing to overall gut health and function.

30. What is the role of M cells in relation to intestinal glands?

M cells are specialized epithelial cells found in the intestinal lining, often associated with lymphoid tissue near intestinal glands. They play a crucial role in the immune system by sampling antigens from the intestinal lumen and presenting them to underlying immune cells, helping to initiate appropriate immune responses.

31. How do intestinal glands contribute to the immune system?

Intestinal glands, particularly in the small intestine, contain Paneth cells that secrete antimicrobial peptides and other immune factors. These help protect the intestinal lining from harmful bacteria and maintain a healthy gut microbiome, contributing to the body's innate immune defense.

32. How do intestinal glands contribute to the barrier function of the intestine?

Intestinal glands contribute to the barrier function of the intestine by producing mucus and antimicrobial peptides, which form a physical and chemical barrier against pathogens. Additionally, the tight junctions between cells lining the glands help maintain the integrity of the intestinal barrier.

33. How do intestinal glands interact with the gut microbiome?

Intestinal glands interact with the gut microbiome in several ways. They secrete antimicrobial peptides that help regulate bacterial populations, produce mucus that provides a habitat for beneficial bacteria, and respond to microbial signals by altering their secretion patterns and immune responses.

34. What is the relationship between intestinal glands and the formation of intestinal organoids?

Intestinal organoids are three-dimensional tissue cultures that mimic the structure and function of intestinal glands. They are derived from intestinal stem cells and can form structures resembling crypts and villi. Studying these organoids helps researchers better understand the development, function, and potential regenerative capabilities of intestinal glands.

35. What is the significance of the "villus-crypt unit" in understanding intestinal gland function?

The villus-crypt unit is the fundamental functional unit of the small intestine, consisting of a finger-like villus projection and its associated crypts (intestinal glands). This arrangement maximizes the surface area for absorption while providing a protected environment for cell renewal and specialized secretory functions, illustrating the integrated nature of intestinal structure and function.

36. How do intestinal glands contribute to the body's circadian rhythms?

Intestinal glands exhibit circadian rhythms in their function, with variations in secretion patterns and cell proliferation throughout the day. These rhythms are influenced by and contribute to the body's overall circadian system, helping to coordinate digestive processes with other physiological functions and environmental cues like meal times.

37. How do intestinal glands contribute to the maintenance of the intestinal stem cell population?

Intestinal glands provide a specialized microenvironment, or niche, that supports the maintenance and function of intestinal stem cells. This niche includes supportive cells, growth factors, and other signaling molecules that regulate stem cell self-renewal and differentiation, ensuring a constant supply of new cells for the intestinal epithelium.

38. What is the relationship between intestinal glands and peristalsis?

Intestinal glands indirectly influence peristalsis, the wave-like muscle contractions that move food through the digestive tract. The secretions from the glands help lubricate the intestinal contents, making them easier to move. Additionally, some hormones produced by enteroendocrine cells in the glands can affect smooth muscle activity and thus influence peristalsis.

39. How do intestinal glands contribute to electrolyte balance?

Intestinal glands play a crucial role in maintaining electrolyte balance by actively secreting and absorbing ions such as sodium, chloride, and bicarbonate. This process helps regulate the body's fluid and electrolyte levels and maintains the proper pH of the intestinal contents.

40. What is the function of brush border enzymes in intestinal glands?

Brush border enzymes are produced by the absorptive cells lining the intestinal glands and villi. These enzymes, such as lactase, sucrase, and peptidases, are located on the cell surface and help break down complex molecules into simpler forms that can be absorbed by the intestinal cells.

41. How do intestinal glands contribute to the absorption of fat-soluble vitamins?

While intestinal glands don't directly absorb fat-soluble vitamins, they contribute to their absorption by secreting bile salts (produced in the liver and stored in the gallbladder) into the intestinal lumen. These bile salts help emulsify fats, creating micelles that facilitate the absorption of fat-soluble vitamins by the intestinal cells.

42. How do intestinal glands adapt to inflammation or injury?

In response to inflammation or injury, intestinal glands can undergo several adaptations. These may include increased production of protective mucus, enhanced secretion of antimicrobial peptides, and accelerated cell renewal to repair damaged epithelium. The stem cells at the base of the glands play a crucial role in this adaptive response.

43. How do intestinal glands contribute to the body's iron homeostasis?

Intestinal glands play a role in iron homeostasis through the absorption of dietary iron. The absorptive cells lining the glands express iron transporters and regulatory proteins that control iron uptake from the intestinal lumen. This process is crucial for maintaining appropriate iron levels in the body.

44. How do intestinal glands contribute to the production and regulation of secretory IgA?

Intestinal glands interact with the gut-associated lymphoid tissue to support the production of secretory IgA, an important antibody in mucosal immunity. Plasma cells near the glands produce IgA, which is then transported across the epithelial cells of the glands and released into the intestinal lumen, providing immune protection.

45. What is the role of intestinal glands in the absorption of water-soluble vitamins?

Intestinal glands increase the surface area available for absorption of water-soluble vitamins. The absorptive cells lining the glands express specific transporters for various vitamins, such as vitamin C and B vitamins, facilitating their uptake from the intestinal lumen into the bloodstream.

46. How do intestinal glands contribute to the body's defense against oxidative stress?

Intestinal glands play a role in defending against oxidative stress by producing antioxidant enzymes and absorbing dietary antioxidants. The cells lining the glands express various antioxidant systems that help protect the intestinal epithelium from oxidative damage, maintaining the integrity of the intestinal barrier.

47. How do intestinal glands contribute to the body's cholesterol metabolism?

Intestinal glands play a role in cholesterol metabolism by expressing proteins involved in cholesterol absorption and excretion. The absorptive cells in the glands can take up dietary cholesterol and also participate in the process of reverse cholesterol transport, contributing to overall cholesterol homeostasis.

48. What is the role of intestinal glands in the production of alkaline phosphatase?

Intestinal glands produce alkaline phosphatase, an enzyme that plays multiple roles in the gut. It helps in the absorption of lipids, regulates intestinal pH, detoxifies bacterial endotoxins, and may contribute to the maintenance of gut barrier function and the regulation of the gut microbiome.

49. How do intestinal glands adapt to changes in osmolarity in the intestinal lumen?

Intestinal glands can adapt to changes in luminal osmolarity by adjusting their secretion and absorption of water and electrolytes. This adaptation involves the regulation of various ion channels and transporters in the gland cells, helping to maintain appropriate fluid balance in the intestine.

50. How do intestinal glands contribute to the body's amino acid metabolism?

Intestinal glands play a role in amino acid metabolism through several mechanisms. The absorptive cells lining the glands express various amino acid transporters for uptake from the intestinal lumen. Additionally, the glands can metabolize certain amino acids and produce others, contributing to overall amino acid homeostasis.

51. How do intestinal glands contribute to the body's response to fasting and feeding?

Intestinal g