Structure and Characteristics of Venule
- Post-capillary venules have a single layer of endothelium surrounded by a basal lamina.
- Size of post-capillary venules is between 10 and 30 micrometers.
- Post-capillary venules do not contain smooth muscle but are supported by pericytes.
- When post-capillary venules increase in diameter to 50μm, they become muscular venules.
- Venules have thinner walls than arterioles due to the poorly developed middle layer.
Short Portal Venules
- Short portal venules exist between the posterior pituitary and the anterior pituitary lobes.
- They facilitate rapid hormonal exchange via the bloodstream.
- Confluent interlobevenules provide blood flow between pituitary lobes, allowing for sharing of information.
- Short portal venules play a role in the anatomical connection between pituitary lobes.
- They provide a pathway for communication within the pituitary gland.
High Endothelial Venules
- High endothelial venules have an endothelium made up of simple cuboidal cells.
- Lymphocytes exit the bloodstream and enter the lymph nodes through these venules during infections.
- Compared to arterioles, high endothelial venules are larger and have a weaker muscular coat.
- They are specialised venules involved in immune response and lymphocyte trafficking.
- High endothelial venules are the smallest united common branch in the human body.
Related Concepts
- Arteriole
- Surface chemistry of microvasculature
- Microcirculation
References
- Standring, Susan (2016). Gray's Anatomy: The Anatomical Basis of Clinical Practice (41st ed.). Philadelphia: ISBN 9780702052309.
- Woods, Susan (2010). Cardiac Nursing. New York: Lippincotts. ISBN 9780781792806.
- Gross, PM; Joneja, MG; Pang, JJ; Polischuk, TM; Shaver, SW; Wainman, DS (1993). Topography of short portal vessels in the rat pituitary gland: A scanning electron-microscopic and morphometric study of corrosion cast replicas. Cell and Tissue Research. 272 (1): 79–88. doi:10.1007/bf00323573. PMID8481959. S2CID23657199.
A venule is a very small vein in the microcirculation that allows blood to return from the capillary beds to drain into the venous system via increasingly larger veins. Post-capillary venules are the smallest of the veins with a diameter of between 10 and 30 micrometres (μm). When the post-capillary venules increase in diameter to 50μm they can incorporate smooth muscle and are known as muscular venules. Veins contain approximately 70% of total blood volume, while about 25% is contained in the venules. Many venules unite to form a vein.
| Venule | |
|---|---|
 Types of blood vessels, including a venule, vein, and capillaries | |
| Details | |
| Identifiers | |
| Latin | venula |
| MeSH | D014699 |
| TA98 | A12.0.00.037 |
| TA2 | 3903 |
| TH | H3.09.02.0.03002 |
| FMA | 63130 |
| Anatomical terminology | |
