Lymph Node Development: Difference between revisions

Revision as of 01:57, 24 February 2012

Introduction

Basic structure of an adult lymph node.

Schematic of lymph node showing lymph sinuses

Lymphatic vasculature drains lymph fluid from the organ tissue space and returns it to the blood vasculature for recirculation. Lymph nodes lie on the path of lymph vessels and these structures monitor and carry out immune surveillance of this fluid for antigens and pathogens, trapping them within the lymph nodes and generating immune responses.

Historic Embryology
1909 Lymph glands \| 1912 Development of the Lymphatic System \| 1918 Gray's Lymphatic Images \| 1916 Pig Lymphatics \| 1919 Chicken Lymphatic \| 1921 Spleen \| 1922 Pig Stomach Lymphatics \| 1932 Cat Pharyngeal Tonsil \| Historic Disclaimer

Some Recent Findings

Lymph sacs are not required for the initiation of lymph node formation^[1] "As proposed by Florence Sabin more than a century ago and recently validated, the mammalian lymphatic vasculature has a venous origin and is derived from primitive lymph sacs scattered along the embryonic body axis. Also as proposed by Sabin, it has been generally accepted that lymph nodes originate from those embryonic primitive lymph sacs. However, we now demonstrate that the initiation of lymph node development does not require lymph sacs."

Adult Lymph Node

Encapsulated organ (1 mm - 2 cm)
In lymph vessel pathways “filter”
Afferent- towards node
Efferent- away from node
Location throughout the entire body - Concentrated in axilla, groin, mesenteries
Antigen transformed lymphocytes from the blood

Links: Immunobiology - Figure 1.8. Organization of a lymph node | MBoC Figure 24-16. A simplified drawing of a human lymph node

Schematic representation of the organization of a lymph node.^[2]

Afferent lymphatics enter lymph nodes and deliver lymph to the subcapsular sinus (SCS), which forms a channel around the periphery of the lymph node.
Lymphatic sinuses run from the SCS through the cortex to the medulla, and exit the lymph node via efferent lymphatic vessels on the opposite, hilar, side of the organ.
B cell follicles containing follicular dendritic cell (FDC) networks are arranged in the lymph node cortex and are separated from the SCS by a layer of marginal reticular cells (MRC).
T cells zones in the paracortex, which contain many fibroblastic reticular cells (FRC), are separated by the cortical ridge, an area rich in T cells, dendritic cells (DCs), blood vessels, and FRC.
Blood vessels enter and exit the lymph node on the hilar side, and snake through the lymph node like the branches of a tree.
Specialized high endothelial venules (HEVs) in the paracortex and cortical ridge allow entry of leukocytes from the blood.

Adult Lymph Node Structure

Capsule - dense connective tissue
Trabeculae - dense connective tissue
Reticular Tissue - Reticular cells and fibers, supporting meshwork
Macrophages - process antigen, difficult to distinguish from the reticular cells.

Lymph

enters the node through afferent vessels
filters through the sinuses
leaves through efferent vessels

Subcapsular sinus = marginal sinus

Continuation of trabecular sinus

Adult Lymphocytes

The following data is from a recent article^[3] and review^[4] of live adult mouse lymphocytes (T and B cells) imaged within a lymph node.

Both lymphocyte types:

Spend 8 to 24 h in the lymph node interstitium.
Transit across a lymphatic endothelium to exit.
Enter a network of medullary sinuses.
Drain from sinuses into efferent lymphatic vessels.

Lymphocyte Migration Speeds

T cells - 10–12 μm/min in the follicle diffuse cortex, peak velocities up to 30 μm/min. (move more slowly in the medullary region near the hilus of the lymph node than in the paracortex)

B cells - 6 μm/min in the follicle diffuse cortex, peak velocities up to 20 μm/min.

Both cortical T cells and follicular B cells move in random directions following "guide cells".

Lymphocyte Guide Cells

FDC - Follicular Dendritic Cells, may guide B cells in the follicle.

FRC - Fibroblastic Reticular Cells, may guide T cells in the follicle.

Lymphocyte Movies

Adult Mouse Lymph Node - T cell motility


Transendothelial migration Quicktime \| Flash	T cell zone Quicktime \| Flash	Medullary sinus Quicktime \| Flash

Sinus endothelial barrier Quicktime \| Flash	Bi-directional traffic Quicktime \| Flash	Cross the sinus endothelial barrier Quicktime \| Flash

References

↑ <pubmed>19060331</pubmed>
↑ <pubmed>19644499</pubmed>| PMC2785037 | Nat Rev Immunol.
↑ <pubmed>16273098</pubmed>
↑ <pubmed>18173372</pubmed>

Reviews

Articles

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Cite this page: Hill, M.A. (2026, April 7) Embryology Lymph Node Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Lymph_Node_Development

What Links Here?

[1] <pubmed>19060331</pubmed>

[2] <pubmed>19644499</pubmed>| PMC2785037 | Nat Rev Immunol.

[3] <pubmed>16273098</pubmed>

[4] <pubmed>18173372</pubmed>

[1]

[2]

[3]

[4]

@@ Line 27: / Line 27: @@
 | [[File:Lymph node structure 02.jpg]]
 | Schematic representation of the organization of a lymph node.<ref><pubmed>19644499</pubmed>| [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2785037 PMC2785037] | [http://www.nature.com/nri/journal/v9/n9/abs/nri2588.html Nat Rev Immunol.]</ref>
-* Afferent lymphatics enter lymph nodes and deliver lymph to the subcapsular sinus (SCS), which forms a channel around the periphery of the lymph node.
+* '''Afferent lymphatics''' enter lymph nodes and deliver lymph to the '''subcapsular sinus''' (SCS), which forms a channel around the periphery of the lymph node.
-* Lymphatic sinuses run from the SCS through the cortex to the medulla, and exit the lymph node via efferent lymphatic vessels on the opposite, hilar, side of the organ.
+* '''Lymphatic sinuses''' run from the SCS through the cortex to the medulla, and exit the lymph node via '''efferent lymphatic vessels''' on the opposite, hilar, side of the organ.
-* B cell follicles containing follicular dendritic cell (FDC) networks are arranged in the lymph node cortex and are separated from the SCS by a layer of marginal reticular cells (MRC).
+* '''B cell follicles''' containing follicular dendritic cell (FDC) networks are arranged in the lymph node cortex and are separated from the SCS by a layer of marginal reticular cells (MRC).
-* The T cells zones in the paracortex, which contain many fibroblastic reticular cells (FRC), are separated by the cortical ridge, an area rich in T cells, dendritic cells (DCs), blood vessels, and FRC.
+* '''T cells zones''' in the paracortex, which contain many fibroblastic reticular cells (FRC), are separated by the cortical ridge, an area rich in T cells, dendritic cells (DCs), blood vessels, and FRC.
 * Blood vessels enter and exit the lymph node on the hilar side, and snake through the lymph node like the branches of a tree.
 * Specialized high endothelial venules (HEVs) in the paracortex and cortical ridge allow entry of leukocytes from the blood.


Transendothelial migration Quicktime \| Flash	T cell zone Quicktime \| Flash	Medullary sinus Quicktime \| Flash

Sinus endothelial barrier Quicktime \| Flash	Bi-directional traffic Quicktime \| Flash	Cross the sinus endothelial barrier Quicktime \| Flash