Lymph node
This image shows a region of cortex with an extension of medullary tissue. Beneath the capsule is the subcapsular sinus, which drains into radially oriented trabecular sinuses that eventually communicate with medullary sinuses. Trabecular sinuses travel with connective tissue trabeculae that extend inward from the capsule toward the medulla. 100x
Capsule >
The capsule surrounding the lymph node is composed of dense connective tissue and sends short trabeculae into the node to provide support.
Trabeculum
The capsule surrounding the lymph node is composed of dense connective tissue and sends short trabeculae into the node to provide support.
Lymphoid nodules >
The outer portion of the cortex, filled with lymphoid nodules, is a B-dependent area. Like all secondary nodules in the immune system, these nodules possess a germinal center with a light and dark region. Antigen stimulation results in the formation of a germinal center that responds by producing additional B lymphocytes.
- Germinal centers
The outer portion of the cortex, filled with lymphoid nodules, is a B-dependent area. Like all secondary nodules in the immune system, these nodules possess a germinal center with a light and dark region. Antigen stimulation results in the formation of a germinal center that responds by producing additional B lymphocytes.
Paracortex (Deep cortex) >
The inner region of the cortex, the paracortex or deep cortex, is a T-dependent area. Under antigenic stimulation, T cells in this region become activated, replicate and leave the lymph node via the efferent lymphatic vessels. These T cells are then returned to the blood and carried to peripheral sites throughout the body.
Medulla >
The medulla of the lymph node consists of medullary sinuses, through which lymph percolates, and medullary cords, composed of B lymphocytes, macrophages, reticular cells and plasma cells.
Subcapsular sinus >
Afferent lymph vessels penetrate the node at its convex surface, where lymph enters the subcapsular sinus. From there, lymph percolates through trabecular (intermediate) sinuses adjacent to trabeculae, and into medullary sinuses. Any foreign matter carried in the lymph is exposed to and processed by macrophages occupying these sinuses.
Trabecular sinuses
Afferent lymph vessels penetrate the node at its convex surface, where lymph enters the subcapsular sinus. From there, lymph percolates through trabecular (intermediate) sinuses adjacent to trabeculae, and into medullary sinuses. Any foreign matter carried in the lymph is exposed to and processed by macrophages occupying these sinuses.
Medullary sinuses
Afferent lymph vessels penetrate the node at its convex surface, where lymph enters the subcapsular sinus. From there, lymph percolates through trabecular (intermediate) sinuses adjacent to trabeculae, and into medullary sinuses. Any foreign matter carried in the lymph is exposed to and processed by macrophages occupying these sinuses.
Medullary cords
Afferent lymph vessels penetrate the node at its convex surface, where lymph enters the subcapsular sinus. From there, lymph percolates through trabecular (intermediate) sinuses adjacent to trabeculae, and into medullary sinuses. Any foreign matter carried in the lymph is exposed to and processed by macrophages occupying these sinuses.
High endothelial venules
Afferent lymph vessels penetrate the node at its convex surface, where lymph enters the subcapsular sinus. From there, lymph percolates through trabecular (intermediate) sinuses adjacent to trabeculae, and into medullary sinuses. Any foreign matter carried in the lymph is exposed to and processed by macrophages occupying these sinuses.
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