Chapter 14: The Lymphatic System Flashcards
lymph
fluid that flows through lymphatic vessels; resembles plasma but contains much lower concentration of suspended proteins
afferent lymphatic vessels
deliver lymph to a lymph node
efferent lymphatic vessels
carry lymph away from lymph nodes toward venous system
Lymphocytes
specialized cells that perform an array of specific functions in bodily defense account for 25% of circulating WBCs
EX: T cells, B cells, NK cells
T cells
-Thymus-dependent
-make up ~80% of circulating lymphocytes
-divided into cytotoxic (killer), helper, suppressor, and memory
- provide cell-mediated (cellular) immunity (defend inside living cells)
complement system (cascade)
-complements the actions of antibodies
(complement Binds to antibody or bacterial cell wall)
-attracts phagocytes
-enhances phagocytosis
-destroys cell membranes
-promotes inflammatory response
B cells
-Bone marrow-derived
-make up ~10-15% of circulating lymphocytes
-responsible for antibody-mediated immunity (defend in body fluid)
-sensitized when antigens enter cell
antigens
A substance capable of inducing the production of antibodies
NK cells
-natural killer cells
-make up ~10-15% of circulating lymphocytes
-respond much more rapidly than T or B cells
-attack foreign cells, normal cells infected with viruses, and cancer cells in normal tissues
-continual monitoring is known as immunological surveillance
Functions of the lymphatic system
-production, maintenance, distribution of lymphocytes
-return of fluids from peripheral tissues to the blood
-distribution of hormones, nutrients, and waste products from peripheral tissues to blood
specific Defenses
(Specific resistance or immunity) is provided by the coordinated activities of T cells and B cells which respond to the presence of specific atigens.
phagocytes
remove cellular debris and pathogens and respond to invasion by foreign compounds or pathogens represent “first line” of cellular defense
neutrophils
50-70% of circulating WBCs; granules are chemically neutralusually the first WBC to arrive at an injury siteactive phagocytes; specialize in attacking bacteria
eosinophils
2-4% of circulating WBCs; stain from red dye = “eosin”attack antibody-labeled materials through release of cytotoxic enzymes and/or phagocytosisnumbers increase dramatically during parasitic infection
four components of lymphatic system
lymphocytes, lymphoid tissues, fluid (“lymph”), vessels
lymphoid tissues
collections of loose connective tissue and lymphocytes in structures called lymphoid nodules
helper T cells
Stimulate both T and B Cells and Coordinate specific/non-specific defenses by stimulating cell-antibody mediated activity
suppressor T cells
act after initial response to dampen/”put brakes on” immune response activated more slowly than other T cells
regulatory T cells
helper and suppressor T cells
lymph nodes
-located in groin (inguinal), armpit (axillary), neck/face (cervical), lumbar area
-purify lymph before it enters venous system
-swollen glands often accompany infection
memory B cells
remain in reserve to respond to subsequent exposure to the same antigen; at which time they differentiate into antibody-secreting plasma cells
thymus
lies in the mediastinum posterior to the sternum
site of T cell production and maturation
IgM
first antibody type secreted following arrival of antigen; levels decline as IgG production accelerate sresponsible for cross-reactions between incompatible blood types
IgA
found in glandular secretions (tears/mucus/saliva) attack pathogens before they enter the body tissues
IgE
accelerate inflammation on exposure to antigen bound to surfaces of mast cells and basophils; stimulates release of histamine; important in allergic response
IgD
bind antigens in the extracellular fluid to B cells
IgG
responsible for defense against many viruses, bacteria, and bacterial toxins; anti-Rh largest class (~80%), can cross placenta and provide passive immunity to fetus
spleen
-largest collection of lymphoid tissue in the body, filters blood rather than lymph
-removes abnormal blood cells and components
-initiates the responses of B and T cells
-stores iron from recycled RBCs
innate immunity
genetically determined; present at birth and independent of previous exposures to antigens
passive immunity
produced by the transfer of antibodies from another person
acquired immunity
Produced by prior exposure or antibody production
active immunity
produced by antibodies that develop in response to antigens (immune response)
natural passive immunity
Conferred by transfer of maternal antibodies across placenta or breast milk.
natural active immunity
Develops after exposure to antigens in enviroment
Basophils
Produce heparine (anti clot) histamines (inflammation)
Phagocytosis
Ingestion of bacteria through phagocytes
Goblet cells
simple columnar epitheleal cells; mucous membranes of the organs
Basal cells
Bottom of the epidermis, produce new skin cells
Septal cells
In alveoli, helps keep alveoli inflated as to not allow collapse
Wandering macrophages
Leaves blood and migrates to infected tissue; macrophages, plasma cells, lymphocytes
Lymphatic pathway
lymphatic capillaries, lymphatic vessels (afferent/efferent), lymphatic duct (right duct and thoracic duct)
Mast cells
Release Histamine and heparin into tissues to support inflammatory response.
Antibodies
A globular protein produced by plasma cells that will bind to specific antigens and promote their destruction or removal from the body
Inflammatory Response
Localized tissue response to injury/Infection
- Swelling, redness, heat, and pain
(triggered by dead cells or damaged connective tissue and slows spread of pathogens)
