Chapter 21 Lymphatic System

Flashcards for Chapter 21 Lymphatic System

Lymph

Fluid similar to plasma but with less protein, containing water, dissolved solutes, and sometimes cell debris, pathogens, or cancer cells.

Lymphatic Capillaries

Small, closed-ended vessels that absorb interstitial fluid.

Fluid Entry into Lymphatic Capillaries

Interstitial fluid enters lymphatic capillaries due to pressure gradients, one-way valves prevent escape.

Mechanisms of Lymph Movement

Skeletal muscle contractions, respiratory pump, and pulsations of nearby arteries.

Major Lymphatic Ducts

Right lymphatic duct and thoracic duct.

Regions Drained by Lymphatic Ducts

Right lymphatic duct drains the right upper limb, right side of thorax and head; thoracic duct drains the rest of the body.

Fluid Entry and Prevention of Escape

Interstitial fluid enters due to pressure; one-way valves prevent escape.

Order of Flow Through Lymphatic Vessels

Capillaries -> Vessels -> Trunks -> Ducts.

Lymphatic Duct Receiving Lymph from Right Leg

Thoracic duct.

Categories of Lymphatic Tissue and Organs

Primary lymphatic structures (red bone marrow and thymus) and secondary lymphatic structures (lymph nodes, spleen, tonsils, lymphatic nodules, MALT).

MALT

Mucosa-associated lymphatic tissue.

Primary Lymphatic Structure Example

Red bone marrow or thymus.

Involution

Shrinkage of an organ, such as the thymus as one ages.

Red Bone Marrow Location and Function

Located within spongy bone; responsible for hemopoiesis.

Major Types of Lymphocytes

B-lymphocytes (B cells) and T-lymphocytes (T cells).

Thymus Structure and Function

Bilobed organ in the superior mediastinum; site of T-lymphocyte maturation.

Location of Hemopoiesis

Red bone marrow.

Thymus Function

T-lymphocyte maturation.

Lymph Node Structure

Small, encapsulated structures located along lymphatic vessels.

Afferent vs. Efferent Lymphatic Vessels

Afferent vessels bring lymph to the node; efferent vessels carry lymph away from the node.

Lymph Node Function

Filter lymph and activate the immune system.

Major Areas with Lymph Node Clusters

Cervical, axillary, and inguinal regions.

Hilum

Indented region on lymph node and spleen where blood and lymphatic vessels and nerves enter.

Spleen and its Location

Largest lymphatic organ, located in the left upper quadrant.

White Pulp vs. Red Pulp

White pulp is associated with the arterial supply and contains lymphocytes and macrophages; red pulp is associated with the venous supply and is a blood reservoir.

Functions of the Spleen

Filters blood, removes old erythrocytes and platelets, stores erythrocytes and platelets, and is a site of fetal hemopoiesis.

Main Groups of Tonsils and their Function

Pharyngeal tonsils (adenoids), palatine tonsils, and lingual tonsils; located in the pharynx; protect against inhaled or ingested pathogens.

Composition of Lymphatic Nodules

Clusters of lymphocytes.

Peyer's Patches

Large collections of lymphatic nodules in the ileum.

Locations of MALT and Peyer's Patches

MALT is found in mucous membranes lining the digestive, respiratory, urinary, and reproductive tracts; Peyer’s patches are found specifically in the ileum.

Ratio of Afferent and Efferent Vessels

Typically, there are more afferent vessels than efferent vessels.

Spleen Side and Hilum Direction

Left side of the body; hilum faces medially.

Relationship of Lymphatic System to Cardiovascular System

Lymphatic system helps maintain fluid balance in the cardiovascular system by returning interstitial fluid to the blood.

Functions of Red Pulp of the Spleen

Acts as a blood reservoir, removes damaged blood cells and pathogens, and filters blood.