Mucosa-Associated Lymphoid Tissue Flashcards

Study mucosa-associated lymphoid tissue, including its distribution, microscopic structure, Peyer's patches, appendix, and immune functions.

Card 1 of 30Question

What does MALT stand for?

Mucosa-associated lymphoid tissue.

In This Section

1. What does MALT stand for?

Mucosa-associated lymphoid tissue.

2. How is mucosa-associated lymphoid tissue classified within the lymphatic system?

As secondary lymphoid tissue.

3. What is the primary function of MALT?

To provide immune surveillance and protection against antigens encountered at mucosal surfaces.

4. In which major body systems is MALT found?

The digestive, respiratory, and genitourinary systems.

5. How does MALT differ structurally from lymph nodes?

MALT is generally unencapsulated lymphoid tissue associated with mucosa, whereas lymph nodes are encapsulated organs.

6. What are the two principal organizational forms of MALT?

Diffuse lymphoid tissue and organized lymphoid follicles or aggregates.

7. What does GALT stand for?

Gut-associated lymphoid tissue.

8. Which anatomical structures are important examples of GALT?

Peyer's patches, the vermiform appendix, and isolated intestinal lymphoid follicles.

9. What does BALT stand for?

Bronchus-associated lymphoid tissue.

10. Where is BALT located?

In lymphoid aggregates associated with the bronchial mucosa and adjacent airway tissues.

11. Is organized BALT consistently present in healthy adult human lungs?

No. Organized BALT is variable and may develop or expand during infection or chronic inflammation.

12. What does NALT stand for?

Nasopharynx-associated lymphoid tissue.

13. Which lymphoid structures form Waldeyer's tonsillar ring?

The pharyngeal, tubal, palatine, and lingual tonsils.

14. What are Peyer's patches?

Aggregated lymphoid follicles associated with the intestinal mucosa.

15. In which part of the small intestine are Peyer's patches most prominent?

The ileum, particularly the distal ileum.

16. On which side of the ileal wall are Peyer's patches commonly concentrated?

Along the antimesenteric border.

17. Which layers of the intestinal wall contain Peyer's patches?

The lamina propria of the mucosa, often extending into the submucosa.

18. What is the follicle-associated epithelium overlying Peyer's patches?

Specialized intestinal epithelium covering lymphoid follicles and containing antigen-sampling M cells.

19. What are M cells in mucosa-associated lymphoid tissue?

Specialized epithelial cells that transport luminal antigens to underlying immune cells.

20. What cellular process allows M cells to transfer antigens across the intestinal epithelium?

Transcytosis.

21. Which lymphocytes predominantly occupy the follicles of Peyer's patches?

B lymphocytes.

22. Where are T lymphocytes primarily concentrated within organized intestinal lymphoid tissue?

In the interfollicular regions surrounding B-cell follicles.

23. What is the significance of germinal centers in MALT follicles?

They support antigen-driven B-cell proliferation, selection, and differentiation.

24. Which antibody class is particularly important in mucosal immune defense?

Immunoglobulin A (IgA), especially secretory IgA.

25. What is the principal function of secretory IgA at mucosal surfaces?

To neutralize pathogens and toxins and limit their attachment to mucosal epithelium.

26. Which lymphoid structures are abundant in the wall of the vermiform appendix?

Lymphoid follicles, often with prominent germinal centers.

27. Which layers of the appendiceal wall contain abundant lymphoid tissue?

The mucosa, particularly the lamina propria, and the submucosa.

28. Why is the vermiform appendix considered part of GALT?

Its abundant lymphoid tissue participates in immune surveillance of intestinal antigens.

29. How does lymph typically leave organized intestinal MALT such as Peyer's patches?

Through efferent lymphatic vessels that drain toward mesenteric lymph nodes.

30. What is MALT lymphoma?

An extranodal marginal zone B-cell lymphoma arising in mucosa-associated lymphoid tissue or similar acquired lymphoid tissue.