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Chapter 21 Lymphoid (Lymphatic) and Immune Systems
immune system
Not an organ system, but a cell population that inhabits all organs and defends the body from agents of disease
pathogens
Organism capable of causing illness
immunity, lipid absorption, fluid recovery
functions of lymphoid (lymphatic) and immune system
lymph
Clear, colorless fluid, similar to plasma but much less protein
lymphatic capillaries (terminal lymphatics)
Penetrate nearly every tissue of the body; Cells tethered to surrounding by protein filaments
lymphatic vessels
Transport the lymph
lymph
The recovered fluid
Lymphoid (lymphatic) tissues
Composed of aggregates of lymphocytes and macrophages that populate many organs in the body
lymphoid (lymphatic) organs
Defense cells are especially concentrated in these organs; Separated from surrounding organs by connective tissue capsules
tunica interna,media,externa
what are the names of the 3 lymphatic vessel layers
lymphatic collecting vessels
Course through many lymph nodes (similar to medium size veins)
lymphatic trunks
Drain major portions of body
Right lymphatic duct
Receives lymph from R arm, R side of head and thorax; empties into R subclavian vein
Thoracic duct
Larger and longer, begins as a prominent sac in abdomen called the cisterna chyli; receives lymph from below
thoracic pump
aids flow from abdominal to thoracic cavity
neutrophils
antibacterial
natural killer (NK) cells
Lymphocytes that attack and destroy infected host cells and cancerous cells; Responsible for immune surveillance
T lymphocytes (T-cells)
Mature in thymus
B lymphocytes (B-cells)
Activation causes proliferation and differentiation into plasma cells that produce antibodies
Macrophages
develop from monocytes: are the man APC’s
lymphoid tissue
aggregations of lymphocytes in the connective tissues of mucous membranes and various organs
diffuse lymphoid tissue
lymphocytes are scattered (not densely clustered)
lymphoid nodules (follicles)
lymphocytes and macrophages gather in dense masses
aggregated lymphoid nodules
large clusters of nodules in the small intestine
lymphoid organs
have connective tissue capsule that separates lymphatic tissue from neighboring tissues
primary lymphoid organs
red bone marrow and thymus; Site where T and B cells (bone marrow) become immunocompetent
secondary lymphatic organs
Lymph nodes, tonsils, and spleen; Location where immunocompetent cells migrate and populate
lymph nodes
most numerous lymphatic organs; cleanse the lymph, alerts immune system to pathogens
afferent
sensory/going up
efferent
leaving/exciting
cervical lymph nodes
Deep and superficial group in the neck
axillary lymph nodes
what lymph nodes are found in the Concentrated in armpit
thoracic lymph nodes
what lymph nodes are found In thoracic cavity (chest), especially embedded in mediastinum
abdominal lymph nodes
what lymph nodes are found in Abdominopelvic wall
intestinal and mesenteric lymph nodes
what lymph nodes are found in Found in mesenteries
inguinal lymph nodes
what lymph nodes are found In the groin
popliteal lymph nodes
what lymph nodes are found in the back of the knee
lymphadenitis
Swollen, painful lymph node responding to foreign antigen
metastasis
Cancerous cells break free original tumor, travel to other sites in the body, and establish new tumors
tonsils
Patches of lymphatic tissue located at the entrance to the pharynx
palatine tonsils
Most often infected; Pair at posterior margin of oral cavity
lingual tonsils
Pair at root of tongue
pharyngeal tonsil (adenoids)
Single tonsil on wall of nasopharynx
spleen
The body’s largest lymphatic organ
red pulp
Sinuses filled with erythrocytes
white pulp
Lymphocytes, macrophages surrounding small branches of splenic artery
spleen
erythrocyte graveyard
innate immunity
Defenses we are born with; protects us from a broad spectrum of disease agents; no prior exposure
adaptive immunity
Defenses against specific pathogens, develops only upon exposure, and maintains immune memory; Results from prior exposure, protects against only a particular pathogen
1st line of defense
skin and mucous membranes
neutrophils
Phagocytize bacteria
eosinophils
Antiparasitic effect
basophils
Aids mobility action of WBCs by release of histamine and heparin
histamine
Increases blood flow to infected area
heparin
Prevents immobilization of phagocytes
monocytes
Circulating precursor to macrophages
macrophages
widely distributed in loose connective tissue
dendritic (langerhan) cells
Oral mucosa, lymphatic organs, esophagus, vagina
microglial cells
Neuroglial cells of CNS
alveolar macrophages
Lungs
hepatic (Kuffer) macrophages
liver
natural killer (NK) cells
continually patrol body looking for pathogens and diseased host cells
perforins
proteins that destroy infected host cells
interferons
Secreted by certain cells infected by viruses; Alert neighboring cells and protect them from becoming infected
fever
An abnormal elevation of body temperature
2nd line of defense
fever
fever benefits
promotes accelerating metabolic rate and tissue repair; inhibiting pathogen reproduction
inflammation
Local defensive response to tissue injury of any kind, including trauma and infection
cellular immunity
Cell-mediated (T cells)
humoral immunity
Antibody mediated (B cells)
antigens
Any molecule that triggers an immune response
haptens (incomplete antigens)
Too small to be antigenic by themselves, but can combine with proteins that render them antigenic
Antibodies, immunoglobulins
Defensive proteins that play a variety of defensive roles
natural active immunity
Production of one’s own antibodies or T cells as a result of infection or natural exposure to antigen
artificial active immunity
Production of one’s own antibodies or T cells as a result of vaccination
natural passive immunity
Temporary immunity that results from antibodies produces by another person
artificial passive immunity
Temporary immunity that results from the injection of immune serum (antibodies) from another personal or animal
IgM
in the process of having it
IgG
you have prior exposure to it
B lymphocytes
develop into Plasma Cells - Produce Antibodies
antigen presenting cells
what cells function as Dendritic cells, macrophages, reticular cells, and B cells
major histocompatibility (MHC) complex
proteins that label every cell of your body as belonging to you
interleukins
Used by lymphocytes and APC’s to communicate
cytotoxic T cells
Carry out attack of enemy cells
helper T cells
Help promote activities of other immune cells
memory T cells
Descend from the cytotoxic cells and are responsible for memory in cellular immunity
recognition
what stage of humoral immunity is when B cell receptors bind antigen; Differentiate into plasma cells, produce antibodies specific to that antigen
attack
what stage of humoral immunity is when antibodies bind to antigen, render it harmless, ‘tag it’ for destruction
memory
what stage of humoral immunity is when some B cells differentiate into memory cells
autoimmune diseases
Immune system does not correctly distinguish self-antigens from foreign ones
immunodeficiency diseases
Vulnerability to opportunistic infection and must live in protective enclosures
aids
Caused by infection with the human immunodeficiency virus (HIV): Invades helper T cells, macrophages, and dendritic cells by “tricking” them to internalize viruses by receptor-mediated endocytosis
aids
can be transferred through sex, contaminated blood products and needles
