6.2 Lymphatic System - Skin and Lymph Nodes

These flashcards cover key terms and concepts from the lymphatic system focusing on the skin and lymph nodes, including cell types, structures, and processes relevant to the immune response.

Keratinocytes

Cells in the outer skin layer that act as a strong physical barrier against microorganisms.

PRRs

Pattern Recognition Receptors that include TLRs, NOD-like receptors, and RIG-1-like receptors, expressed by skin immune cells to detect pathogens.

Langerhans cells

Dendritic cells in the epidermis that promote Th17 responses against extracellular pathogens and regulate immune tolerance.

αβ T cells

A subtype of T cells found in both the epidermis and dermis, involved in immune responses.

γδ T cells

A subtype of T cells located in the skin that contribute to immune responses.

Dendritic cells (DC)

Professional antigen presenting cells derived from bone marrow; they capture and present antigens to T cells.

Follicular dendritic cells (FDC)

Non-hematopoietic stromal cells that present intact antigens to B cells in lymphoid follicles.

HEV (High Endothelial Venules)

Specialized blood vessels in lymph nodes allowing lymphocytes to enter from the bloodstream.

Germinal center

Area in secondary lymphoid follicles where B cells undergo proliferation, clonal expansion, and affinity maturation.

Centroblasts

Rapidly dividing B cells found in the dark zone of the germinal center.

Somatic hypermutation

A process in which B cells undergo mutations in their variable region genes to increase antibody affinity.

Affinity maturation

The process where B cells are selected for higher affinity antibodies during immune responses.

Plasma cells

Differentiated B cells that produce antibodies and can reside in the medullary cords or bone marrow.

Memory cells

Long-lived immune cells that respond more effectively upon subsequent exposure to an antigen.

Subcapsular sinus macrophages

Macrophages in the lymph node that capture and display antigens tagged with complement.

Medullary sinus macrophages

Highly phagocytic macrophages in the lymph node that filter lymph and destroy pathogens.