Intro to the Lymphatic System

Flashcards covering the anatomy, components, functions, and cellular structures of the lymphatic system and its role in immunity.

Lymphatic vessels

A network of vessels providing a one-way flow of lymph that returns back towards the heart.

Lymphatic system components

The system consists of three main parts: a network of lymphatic vessels, lymph fluid (interstitial fluid and leaked plasma proteins), and lymph nodes.

Chyle

A milky fluid found in the lacteal system of the intestine that helps absorb fatty acids into the portal circulation or blood vessel circulation.

Lacteals

Small parts of the small intestine that absorb fat and contain chyle.

Lymph nodes

Bean-shaped collections of tissue that filter pathogens and provide a structural basis for the immune system.

Pathogen

A microbe that causes disease, such as bacteria, viruses, or parasites.

Interstitial fluid

Fluid found between cells in the tissue spaces that forms when blood plasma filters through blood capillary walls.

Lymph

Interstitial fluid once it has passed into lymphatic vessels or lymphatic tissue.

Palatine tonsils

A type of lymph nodule located near the hard and soft palate important for stopping germs that enter through the oral or nasal cavities.

Axilla

The armpit region, which contains a high concentration of axillary lymph nodes.

Cisterna chyli

An abdominal structure that serves as the origin of the thoracic duct and receives lymph from the lumbar lymphatic trunks.

Thoracic duct

The large duct that drains lymph from the lower body and the left side of the body.

Right lymphatic duct

The duct that drains lymph from the upper right quadrant of the body.

Lymphoma

A type of cancer that originates specifically in the lymph nodes.

Metastasis

The process where cancer moves and spreads from its original site to other parts of the body, such as the lymph nodes.

Edema

Tissue swelling that occurs when lymphatic vessels fail to drain excessive interstitial fluid properly.

Dietary lipid transport

The function of the lymphatic system to transport lipids and lipid-soluble vitamins, specifically vitamins $A$, $D$, $E$, and $K$, absorbed through the gastrointestinal tract.

Lymphatic capillaries

The smallest lymphatic vessels, which are closed at one end and located in spaces between cells.

Anchoring filaments

Projections made of elastin that help anchor lymphatic capillaries to surrounding tissue cells.

B cells

Lymphocytes that produce antibodies used to attack invading bacteria, viruses, and toxins.

T cells

Lymphocytes able to destroy the body's own cells that have been compromised by viruses or show cancerous changes.

Avascular tissues

Tissues that lack lymphatic capillaries because they have no vascular system, including cartilage, the epidermis, hair, nails, the cornea, tooth enamel, and parts of the CNS.

Skeletal muscle pump

A milking action where skeletal muscle contractions compress lymphatic vessels to push fluid against gravity back towards the heart.

Respiratory pump

A mechanism where lymph flow is maintained by pressure changes that occur during inhalation.

Thymus gland

A primary lymphoid organ located in the mediastinum anterior to the major blood vessels of the heart; it is the site of T lymphocyte maturation.

Primary lymphoid organ

An organ involved in creating the cells used in immune responses, such as the thymus gland.

Secondary lymphoid organs

Organs and tissues that are involved in actually fighting the immune response, such as lymph nodes and the spleen.

Atrophy

The process of shrinking in size, as seen in the thymus gland starting from adolescence.

Immunocompetency

The ability of the body to produce a normal immune response.

Dendritic cells

Cells in the lymph nodes that capture, process, and present antigens to lymphocytes.

Macrophages

Large immune cells that destroy microorganisms and cellular debris through the process of phagocytosis.

Spleen

The largest single lymphoid organ, located in the upper left abdominopelvic cavity, responsible for lymphocyte proliferation and blood cleansing.

White pulp

Splenic tissue surrounding central arteries that is mostly involved in immune function and contains lymphocytes.

Red pulp

Splenic tissue consisting of venous sinuses and splenic cords, rich in macrophages for the disposal of worn-out red blood cells.

MALT

Mucosal Associated Lymphatic Tissue; lymphatic nodules found in mucous membranes like the oral cavity and gastrointestinal system.

Peyer's patches

Aggregated lymphatic nodules found throughout the ileum of the small intestine.

Germinal centre

An area within lymphoid follicles and tonsils mainly comprising proliferating B cells, dendritic cells, and macrophages.

Tonsillar crypt

A structure in the tonsils that functions to capture antigens and initiate the adaptive immune response.