Lymphoid System and Immunity Lecture Notes

Comprehensive vocabulary flashcards covering the components, functions, flow, and cellular structure of the lymphoid and immune systems based on lecture notes.

Lymph

Clear and colorless fluid, containing no protein, that collects in interstitial spaces of tissue and returns to the bloodstream.

Lymphatic vessels

Vessels that transport lymph throughout the body.

Lymphoid tissue

Clusters of lymphocytes located in the connective tissue of mucous membranes and other organs.

Lymphoid organs

Concentrations of lymphoid cells set off from surrounding organs by connective tissue.

Fluid recovery

The lymphoid system function of reabsorbing excess fluid and returning it to the blood; failure of this process leads to lymphedema.

Immune surveillance

The monitoring and reporting of impurities or invasions within the body.

Lacteals

Specialized structures that absorb dietary lipids which cannot be absorbed by intestinal blood capillaries.

Chyle

A milky fluid from the small intestine found in the lymphatic system.

Lymphatic anchoring filaments

Filaments that prevent the sac of thin endothelial cells in lymphatic capillaries from collapsing.

Valvular flaps

Overlapping edges of endothelial cells in lymphatic vessels that open when tissue pressure is high and close when lymphatic capillary pressure is high.

Right lymphatic duct

Duct formed by the right jugular, subclavian, and bronchomediastinal trunks that receives lymph from the right upper limb, right side of the thorax, head, brain, and spinal cord.

Thoracic Duct

A larger and longer duct beginning below the diaphragm as two lumbar trunks and an intestinal trunk that empties into the left subclavian vein.

Glymphatic system

A glial-associated lymphatic system of the brain where CSF filters via perivascular feet to mix with tissue fluid and rinse metabolic waste.

T lymphocytes

Lymphocytes that mature in the thymus; include Helper t cells and Cytotoxic T cells.

B lymphocytes

Lymphocytes that mature in the bone marrow and differentiate into antibody-secreting plasma cells after activation.

MALT

Mucosa-associated lymphoid tissue; diffuse lymphoid tissue found in mucous membranes such as the respiratory and digestive tracts.

Aggregated lymphoid noodles

Clusters of lymphoid tissue found in the ileum and distal portion of the small intestine.

Macrophage system

A system that breaks down tissue debris, old RBCs, and dead neutrophils while secreting growth factors and acting as antigen representing cells.

Primary lymphoid organs

The Red bone marrow and thymus; the locations where T and B cells become immunocompetent.

Secondary lymphoid organs

The lymph nodes, tonsils, and spleen; where immunocompetent cells migrate after maturation.

Hilum

An indentation in a lymph node.

Subcapsular sinus

A region in the lymph node containing reticular fibers, macrophages, and dendrites cells.

Tonsils

Lymphoid tissue in the pharynx with deep pits called tonsillar crypts that protect against ingested and inhaled pathogens.

Red pulp

Region of the spleen consisting of sinusoids filled with erythrocytes.

White pulp

Region of the spleen consisting of lymphocytes and macrophages.

Innate immunity

Fast-acting defense mechanisms one is born with, including fever and inflammation, which lack memory of pathogens.

Adaptive immunity

Immunity that remembers and responds specifically to each pathogen using B and T cells.

Negative selection

A process lymphocytes must survive in order to become immunocompetent.