Ch21_lymphatic_system

Lymphatic System

A system consisting of lymphoid tissues and organs that helps return leaked fluids back to the blood and houses immune cells.

Hydrostatic Pressure

The pressure exerted by a fluid at equilibrium due to the force of gravity; influences fluid movement in capillaries.

Colloid Osmotic Pressure (COP)

The pressure exerted by proteins in the blood plasma that draws water into the circulatory system.

Filtration

The process of fluid being forced out of capillaries due to hydrostatic pressure.

Reabsorption

The process where fluid is drawn back into capillaries primarily due to colloid osmotic pressure.

Lymphatic Capillaries

Small, blind-ended vessels that pick up interstitial fluid and turn it into lymph.

Lymph

The fluid that is collected in lymphatic capillaries, containing proteins, bacteria, and waste.

Skeletal Muscle Pump

A mechanism that aids lymphatic flow, where muscle contractions push lymph through lymphatic vessels.

Respiratory Pump

A mechanism that assists in lymph movement by changing intra-thoracic pressure during breathing.

Lymphedema

Swelling caused by the accumulation of lymph, often due to the obstruction of lymphatic vessels.

Elephantiasis

A condition characterized by massive swelling due to lymphatic obstruction, often caused by filarial worms.

Lymphocytes

A type of white blood cell found in the lymphatic system, including T cells and B cells.

Macrophages

Cells that phagocytose foreign substances and help activate the immune system.

Dendritic Cells

Immune cells that capture and present antigens to T cells, facilitating an immune response.

Primary Lymphatic Structures

Organs such as red bone marrow and thymus where lymphocytes are formed and mature.

Secondary Lymphatic Structures

Organs such as lymph nodes and the spleen that house mature lymphocytes and support immune responses.

Tonsils

Lymphoid tissues forming a ring around the throat that trap pathogens for immune activity.

Peyer’s Patches

Aggregated lymphoid nodules in the small intestine that monitor intestinal bacteria and prevent infection.

MALT (Mucosa-Associated Lymphoid Tissue)

Lymphoid tissues located in mucous membranes that serve as the first line of defense against pathogens.