Chapter 21 study guide

Composition of Lymph

Lymph is a clear fluid that contains lymphocytes, proteins, waste products, and fats absorbed from the digestive tract.

Structure of Lymphatic Capillaries

Lymphatic capillaries are blind-ended tubes that are thinner than blood capillaries, feature larger fenestrations, and lack a basement membrane.

Location of Lymphatic Capillaries

Lymphatic capillaries are located throughout the body tissues, found alongside blood capillaries.

Entry of Interstitial Fluid into Lymphatic Capillaries

Interstitial fluid enters lymphatic capillaries via inward-folding spaces between lymphatic endothelial cells that act as one-way flaps.

Functions of the Lymphatic System

Primary functions include maintaining fluid balance and facilitating immune responses; secondary functions include absorption of fats and fat-soluble vitamins.

Functions of Lymph Nodes

Lymph nodes filter lymphatic fluid, trapping pathogens and foreign particles, and house immune cells that can attack these foreign particles.

Functions of Spleen

The spleen filters blood, removes old or damaged blood cells, produces lymphocytes, and stores platelets.

Location & Function of the Thymus

The thymus is located behind the sternum and is involved in the maturation of T lymphocytes essential for adaptive immunity.

Forces Moving Interstitial Fluid into Lymph

Hydrostatic pressure from arteries, pressure changes from breathing, and skeletal muscle contractions help move interstitial fluid into the lymphatic system.

Lymph Drainage pathways

Lymph from the lower body drains into lumbar trunks, to the cisterna chyli, into the thoracic duct, and finally into the right subclavian vein.

Difference between Primary & Secondary Lymphatic Structures

Primary structures are where lymphocytes are produced and mature; secondary structures are where immune responses are initiated.

Difference between T & B Lymphocytes

T lymphocytes are involved in cell-mediated immunity, while B lymphocytes are responsible for antibody-mediated immunity by producing antibodies.

Basic Structure of Lymphoid Organs

Lymphoid organs consist of dense irregular connective tissue and leukocytes involved in the immune response.

Basic Facts about MALT & GALT

MALT is in mucosal tissues protecting mucosal barriers; GALT is associated specifically with the digestive tract.

Basics of Tonsils

Tonsils are lymphoid tissues at the back of the throat, consisting of palatine, pharyngeal, and lingual tonsils, protecting against pathogens.

Metastasis

The process by which cancer cells spread from one part of the body to another, often via the lymphatic system or bloodstream.

Lymphoid Nodules

Small clusters of lymphoid tissue that play a role in immune response, commonly found in the gastrointestinal tract mucosa.

Lymphedema

Localized fluid retention and tissue swelling caused by a compromised lymphatic system, often from surgical removal of lymph nodes.