Lacteals (Intestinal Lymph Capillaries) Flashcards

Explore intestinal lacteals, their villous structure, lipid absorption, chyle formation, lymphatic drainage, and clinical significance.

Card 1 of 26Question

What are intestinal lacteals?

Specialized lymphatic capillaries within intestinal villi that absorb and transport dietary lipids.

In This Section

1. What are intestinal lacteals?

Specialized lymphatic capillaries within intestinal villi that absorb and transport dietary lipids.

2. In which anatomical layer of the small intestine are lacteals located?

The mucosa, specifically within the lamina propria of intestinal villi.

3. What is the typical position of a lacteal within an intestinal villus?

It occupies a central position within the connective tissue core of the villus.

4. Which part of the gastrointestinal tract contains intestinal lacteals?

The small intestine, including the duodenum, jejunum, and ileum.

5. What type of vessel is a lacteal?

A blind-ended initial lymphatic capillary.

6. Which cells form the walls of intestinal lacteals?

A single layer of specialized lymphatic endothelial cells.

7. How does the basement membrane of a lacteal differ from that of a typical blood capillary?

Lacteals have a discontinuous or poorly developed basement membrane.

8. What is the principal absorptive function of intestinal lacteals?

Uptake of chylomicrons containing absorbed dietary long-chain lipids.

9. What are chylomicrons?

Lipoprotein particles that transport dietary triglycerides, cholesterol, and fat-soluble vitamins.

10. Which intestinal epithelial cells assemble and release chylomicrons?

Enterocytes, the absorptive epithelial cells lining intestinal villi.

11. Why are chylomicrons primarily absorbed into lacteals rather than intestinal blood capillaries?

Their relatively large size limits direct entry into blood capillaries but permits lymphatic uptake.

12. What is chyle?

Intestinal lymph rich in absorbed dietary lipids, particularly chylomicrons.

13. Why does intestinal lymph often appear milky after a fat-rich meal?

Because it contains high concentrations of triglyceride-rich chylomicrons.

14. Which dietary fatty acids are commonly absorbed directly into intestinal portal blood rather than through lacteals?

Short-chain and medium-chain fatty acids.

15. Which vitamins are transported with dietary lipids through intestinal lacteals?

The fat-soluble vitamins A, D, E, and K.

16. Which type of endothelial junction facilitates chylomicron entry into intestinal lacteals?

Discontinuous, button-like junctions between lymphatic endothelial cells.

17. How do smooth muscle cells within intestinal villi assist lacteal function?

Their contractions help propel lymph from lacteals into downstream lymphatic vessels.

18. Where does lymph flow after leaving the central lacteals of intestinal villi?

Into lymphatic networks within the intestinal wall and then mesenteric collecting lymphatics.

19. Which lymph node group filters most lymph draining from the jejunum and ileum?

The superior mesenteric lymph nodes.

20. Which major lymphatic trunk receives intestinal lymph after it passes through abdominal lymph nodes?

The intestinal lymphatic trunk or trunks.

21. Which lymphatic structure commonly receives intestinal lymph before it enters the thoracic duct?

The cisterna chyli, when present as a distinct lymphatic sac.

22. Through which major lymphatic vessel do absorbed intestinal chylomicrons ultimately reach the venous circulation?

The thoracic duct.

23. What is intestinal lymphangiectasia?

Abnormal dilation of intestinal lymphatic vessels, including lacteals.

24. How can intestinal lymphangiectasia cause protein-losing enteropathy?

Dilated lymphatics may leak or rupture, allowing protein-rich lymph to escape into the intestinal lumen.

25. What nutritional consequence can result from impaired lacteal function?

Fat malabsorption with possible deficiencies of fat-soluble vitamins.

26. What characteristic histological finding may be seen in intestinal lymphangiectasia?

Dilated lymphatic channels within the intestinal villi and sometimes deeper intestinal layers.