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Chapter 14 (kahoot (the least numerous leukocyte are basophils, which of…
Chapter 14
kahoot
the least numerous leukocyte are basophils
which of the following is the LAST step in inflammation? phagocytosis
the most active phagocytic cells found in circulating blood are neutrophils and monocytes
unnecessary immune responses to antigens are allergies
which of the following contains visible granules in its cytoplasm? neutrophils
the human immunodeficiency virus (HIV) that causes the disease known as AIDS selectively infects the helper T cells
the first line of cellular defense against pathogens is phagocytes
infection with the HIV virus occurs through intimate contact with an infected person's body fluids
virus-infected cells release interferon
which of the following is an autoimmune disease? all of the above
interferons may be described as all of the above
one of the most common cancers seen in AIDS patients is kaposi's sarcoma
special lymphocytes that are part of the nonspecific defenses are called NK cells
changes in the immune system that accompany aging include T cells becoming less responsive to antigens
the body's nonspecific defenses include all of the above
with advancing aging the immune system becomes less effective at combating disease
major events associated with inflammation include redness, swelling, heat, and pain
the increased incidence of cancer in the elderly reflects the fact that immune surveillance declines with age
14.2
Major Components
Lymphocytes
Lymphoid Tissues
Lymph
Lymphoid Organs
Lymphatic Vessels
Major Functions
Return fluid and solutes from peripheral tissue to the blood
Distribution of hormones, nutrients, and waste products from their tissues of origin to the general circulation
Production, maintenance, and distribution of lymphocytes
Lymphatic Capillaries
Are associated with anchoring filaments, which serve an important function during edema (general swelling)
are located throughout the body, except in avascular tissues, CNS, splenic pulp, bone marrow
Receive lymph through their thin walls
include lacteals that are lymphatic capillaries within villi of the small intestine
Are microscopic closed-ended tubes that extend into interstitial spaces
Lymphatic Vessels
are formed by the merging of lymphatic capillaries
have walls similar to veins and possess valves that prevent back flow of lymph
lead to lymph nodes as "afferent" LVs leave lymph nodes as "efferent" LVs and then merge into lymphatic trunks
Lymphatic Trunks
drain lymph from relatively large body regions
principal lymphatic trunks include the follow, lumbar, intestinal, bronchomedianstinal, subclavian, jugular, intercostal
pass their lymph into venous blood by joining one of two collecting ducts
Collecting ducts
right lymphatic duct drains the right upper body (25% of total body)
thoracic (left lymphatic) duct drains the remaining 75% of the body's lymph. Between left subclavian and left internal jugular veins
Tissue Fluid Formation (lymph)
tissue fluid is blood plasma that has passed through cardiovascular capillary walls into interstitial spaces, minus large plasma proteins
recalls the constituents of plasma, water and dissolved substances including small plasma proteins, nutrients, wastes, gases, electrolytes, enzymes, and hormones
Lymph Formation
increasing pressure forces tissue fluid into lymphatic capillaries
this fluid is now called lymph
As protein concentration in interstitial spaces increases, its pressure increases
lymph formation prevents accumulation of excess tissue fluid (prevents edema)
Lymph Function
returns small leaked plasma proteins back to the bloodstream
transports foreign particles to the lymph nodes
transports lipids and lipid-soluble vitamins absorbed in GI tract to bloodstream
Lymph Movement
Lymph flow, lymph is under low pressure and may not flow readily without aid from external forces (similar to venous return) the squeezing action of skeletal muscles aids movement, the low pressure in the thoracic cavity created by breathing movements moves lymph up from abdominal to thoracic region, recall the prescence of one-way valves
obstruction of lymph movement- any condition that interferes with the flow of lymph results in edema, edema= accumulation of excess interstitial fluid leading to swelling of tissues, tissue swelling pulls on anchoring filaments making openings between cells even larger so that mire fluid can move into the lymphatic capillary (reduction swelling) the surgical removal of lymph nodes causes obstruction and results in edema (accompanying mastectomy)
Lymphocytes
circulating lymphocytes
t cells (thymus dependent) 80%, cytotoxic T cells (cell-mediated immunity) helper T cells stimulates both T and B cells, suppressor T cells inhibit both T and B cells
B cells (bone marrow derived) 10-15%. differentiate into plasma cells (produce) immunoglobulins (antibodies) bind to antigens, antibody-antigen complex immunity. antibody mediated (humoral immunity) antibodies function in body fluids
NK cells (natural killers) 5-10%, attacking foreign cells virus infected cells and cancer cells, immunological survellance
Lymphopoiesis
hemocytoblast (bone marrow) B cells stay in bone marrow, T cells go to thymus (thymosins)
Lymphatic tissues
primarily lymphatic organs, are the sites of production of immunocompetent cells, B cells and T cells, bone marrow (Red), thymus
secondary lymphatic organs are the sites where most immune responses occur, lymph nodes, spleen
Lymph nodules- when it is not encapsulated, it is called diffuse lymphatic tissue (found in submucosa of mucous lining), also known as M.A.L.T. mucus associated lymphatic tissue, tonsils 5 pairs (tonsillitis) tonsillectomy (Adenoids (pharyngeal) palatine, lingual (under base of tongue)) peyer patches under epithelium of digestive system, appendix (appendicitis) appendectomy junction near small and large intestine
Thymus
soft, bilobed organ located within the mediastium, decreases in size (atrophy) after puberty, composed of lymphatic tissue that is subdivided into lobules, each lobule contains an outer (dark staining) cortex filled with densely packed lymphocytes around a central medulla (light staining) filled with swirled epithelial cells (called Hassall's corpuscles)
Spleen
upper left portion of the abdominal cavity behind stomach, resembles a large lymph node that is encapsulated and subdivided into lobules by connective tissue, white pulp=lymphocytes arranged around central arteries, red pulp= blood filled sinuses (venous blood that also serves as blood reservoir)
14.6
direct attachment involves the following, agglutunation, predipitation, neutralization
activation of complement, opsonization, cherhotaxis, inflammation, lysis
antibody molecules, two heavy chains, two light chains, variable regiors
IgA, about 13% of circulating antibodies, occurs in endocrine gland secretions, defends against bacterial cells and virsuses, levels decrease during stress, lowering resistance to infections
IgG, most abundant circulating antibody (80% in total), occurs in plasma and tissue fluids, defends against bacterial cells virsuses and toxins, activates complement, only antibody to cross placenta
IgM, about 6%, first antibodies to be secreted after initial exposure to an antigen, occurs in plasma, produced in blood transfusions, activates complement
IgD <1% of antibodies, occurs on the surface of most B cells, involved in activation of B cells
IgE, <0.1% of antibodies, occurs in exocrine gland secretions, promotes inflammation and allergic reactions because they cause the release of histamine from mast cells (basophils)
when B or T cells first encounter an antigen for which they are specialized to react, the reaction is called a primary IR
during this reponse, antibodies are produced for several weeks (IgM)
a secondary IR occurs rapidly if the same antigen is encountered at a later time(IgG)
14.7
immune complex allergic reactions (type 3) involve autoimmunity, which is an IR against self-antigens
antibody-dependent cytotoxic allergic reactions type 2 occur when blood transfusions are mismatched
delayed reaction allergy,(type 4) which can occur in anyone and can cause inflammation of the skin, results from repeated exposure to antigenic substances
immediate reaction allergy type 1 whihc is inherited causes the production of an abnormally large amount of IgE
allergic reactions involve antigens combining with antibodues (IgE) the resulting IR is likely to be excessive or violent and may cause tissue damage
allografts occur between individuals of the same species, kidney transplant from a relative
autografts- are "self" grafts a skin graft from one part pf the body to another
xenografts occur between individuals of different species, a pig heart valve into a human
isografts- occur between identical twins, a bone marrow transplant from a healthy twin to one with leukemia
14.4
naturally aquired active immunity, a person who encounters a live pathogen, which stimulates a primary IR, and suffers symptoms of the disease
induced acquired active immunity, person recieves a vaccine containing a dead or weakened pathogen, stimulation of the IR causes the person to have this
induced acquired passive immunity, recieves an injection of gamma globulin that contains ready-made antibodies , patient does not have time to develop active immunity no IR occurs, immunity provided is short term
naturally acquired passive immunity, when antibodies (IgG) pass through placental membrane from a pregnant women to her fetus, short term immunity w/o development of IR
adaptive (specific) defenses/immunity
3rd line of defense
antigens (Ag's) substance (usually a protein) that causes the formation of an antibody and reacts specifically with that antibody
t cells respond to antigens directly (cell on cell contact), secrete cytokines to enhance other immune responses to antigens, colony stimulating factors stimulates bone marrow to produce lymphocytes, interferons block viral replication, stimulate macrophages to engulf viruses, stimulate B cells to produce antibodies
14.5
memory T cells are produced upon initial exposure to an antigen, they allow for immediate response against subsequent exposures to the same antigen
cytotoxic T cells recognize foreign antigens on tumor cells and virsus infected cells
helper T cells (CD4) become activated when they encounter a displayed antigen on an APC for which it is specialized ti react, once activated helper T cells stimulate B cells to produce antibodies, CD4 helper t cells stimulate antibody mediated immunity (AMI) abnd secrete cytkines (CMI), HIV virsus cripples this
stimulated cytotoxic t cells proliferate into a large clone of cells that secrete perforin to destroy target cells
Natural killers also use perfoorins to destroy tumor cells
14.3
innate (nonspecific) defenses
physical barriers
skin, mucus membrane, hair, cilia, urine, defecation, vomiting
chemical barriers
lysozyme, gastric acid, saliva, acidity, sebum, hyaluronic acid
second line of defense
phagocytosis
microphages (neutrophils/eosinophils) macrophages (monocytes)
the most active phagocytes in the blood are neutrophils and monocytes
immunological surveillance, natural killer cells, special lymphocytes, attack foreign material, microbes, cancer cells, use perforins to rupture cell membranes, enhance inflammation, interferons, complement system, inflammation, fever
14.1
Pathogen
various microorganisms that cause disease in humans including viruses, bacteria, fungi, and parasites
Nonspecific Defense
do not distinguish between one potential threat to another
Specific Defense
Lymphocytes organize a defense against a particular type of pathogen