Lymphatic System Part One Review

Flashcards covering key vocabulary from the lymphatic system lecture.

Edema

General swelling.

Lymphedema

A specific type of swelling and fluid buildup caused by a blocked lymphatic vessel, preventing lymph drainage, typically in an arm or leg.

Lymph

Excess interstitial fluid that has entered lymphatic vessels.

Lymph nodes

Structures through which lymph passes and where lymphocytes congregate, processing lymph before it returns to the blood.

Lymphatic vessels

Vessels that transport lymph throughout the body, characterized by large diameter, thin walls, and numerous one-way valves to ensure forward flow.

Lymphatic capillaries

Terminal, pocket-like vessels with overlapping endothelial cells that act as one-way valves, allowing fluid in but not out.

Lymphocytes

A specific type of white blood cell, representing 20-30% of circulating white blood cells, though most are found in lymphatic tissues.

T cells (Thymus-dependent cells)

Lymphocytes that mature in the thymus and are responsible for specific immunity, representing about 80% of all lymphocytes.

B cells (Bone marrow-derived)

Lymphocytes that mature in the red bone marrow and are responsible for specific immunity.

NK cells (Natural Killer cells)

Lymphocytes that mature in the bone marrow and are responsible for non-specific immunity.

Cytotoxic T cells (CD8 cells)

T cells that directly attack and kill foreign cells or virus-infected cells, identified by their CD8 surface glycoprotein.

Helper T cells (CD4 cells)

T cells that stimulate the function of other T cells and B cells to facilitate the immune response, identified by their CD4 surface glycoprotein.

Antigen presentation

The process by which an antigen is formally displayed to T cells for their activation.

Antigen

A specific ID or molecule on an invader, infected cell, or abnormal cell that the immune system recognizes.

Antigen-presenting cells (APCs)

Immune cells (e.g., dendritic cells, macrophages, B cells) that engulf foreign cells, process their antigens, and display them on their surface via MHC II.

Phagocytosis

The process by which cells engulf solid particles, such as bacteria.

MHC II (Major Histocompatibility Complex II)

A surface complex found on antigen-presenting cells that displays processed antigens to helper T cells.

CD4

A surface glycoprotein on helper T cells that binds to MHC II during antigen presentation, activating the helper T cell.

Plasma cells

Differentiated B cells that are responsible for producing and secreting antibodies.

Antibodies

Proteins produced by plasma cells that specifically bind to antigens, marking them for destruction or neutralization.

Cytokines

Chemical messengers, such as interleukins, released by activated helper T cells to stimulate and coordinate other immune cells.

Interleukins

A type of cytokine that signals T cells to divide and activate, contributing to the immune response.

MHC I (Major Histocompatibility Complex I)

Proteins displayed on the surface of all nucleated body cells that present either normal self-antigens or abnormal antigens from infected, cancerous, or foreign cells.

CD8

A surface glycoprotein on cytotoxic T cells that binds to MHC I complexes displaying abnormal antigens, activating the cytotoxic T cell.

Apoptosis

A form of programmed cell death, which cytotoxic T cells can trigger in target cells to destroy them.