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201 Cards in this Set
- Front
- Back
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1) Most of the lymph enters the blood stream into which vessel?
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Left subclavian vein
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2) The only organs to filter lymph are?
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Lymph nodes
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3) The only lymphatic organ to filter blood is?
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Spleen
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4) The lymphatic organ that produces hormones and is involved in maturation of T lymphocytes is?
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Thymus
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5) The bactericidal enzyme secreted in mucus membranes is?
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Lyosozome
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6) The enzyme secreted by certain pathogens in that can dissolve the viscous ground substance in areolar tissue is?
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hyaluronodaise
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7) The release of superoxide (O2-), hydrogen peroxide (H2O2), and hypocholorite ion HCLO-, by neutrophils is referred to as a?
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respiratory burst
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8) Type of leukocyte with antiparasite activity and is also linked to allergic response?
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eosinophil
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9) Lymphocyte that is active in nonspecific attack against viral or bacterial infected cells?
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Natural Killer cells
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10) Circulating leukocytes that are precursors to macrophages?
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monocytes
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11) Inflammatory leukocyte that releases histamine and heprin and attracts other WBCs to the area of inflammation?
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Basophil
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12) Process of leukocytes adhering to wall of blood vessel?
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margination
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13) Process of leukocytes squeezing through capillary walls?
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diepedesis
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14) Type of leukocyte that quickest to respond and begin phagocytosis?
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neutrophil
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15) Phagocytic leukocyte that is the second to respond to an area of infection (8-12 hours)?
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monocytes
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16) Factor released by endothelial cells and platelets that stimulates fibroblasts to bein synthesizing collagen
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PDGF
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17) Polypeptide secreted by virally infected cells that has protective effect on surrounding cells?
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Interferon
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18) Group of 20 enzyme like proteins in the blood that enhance inflammation and antimicrobial activity?
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compliment system
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19) Covering of bacterial surface that permits or enhances phagocytosis by macrophages ?
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opsinization
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20) Protein produced by macrophages that stimulates the hypothalamus to secrete PDE which leads to fever?
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pyrosin
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21) Antibody mediated specific immunity?
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humoral immunity
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22) Molecules that can evoke an immune response and are usually (but not always proteins?
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antigens
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23) Area on antibody that binds foreigh materials?
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antigen binding site
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24) Class of antibody that is a pentamer and is involved in the initial immune response?
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IgM
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25) Class of antibody that is involved with secondary immune response and is the most abundand of the antibodies?
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IgG
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26) Class of antiodies involved in secretions such as tears, saliva and intestinal juices?
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IgA
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27) Antibody action that causes the antigen adn antibody to form a solid particle that can be phagocytosed?
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Precapitation
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28) Hormones like messengers between lymphocytes?
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interleukins
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29) Type of lymphocyte involved in humoral immunity?
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B-cells
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30) Active antibody producing cells in blood?
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plasma cells
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31) Type of lymphocyte that is directly involved in attacking viral infected cells?
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Killer T cells
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32) Type of lymphocyte that is involved in the activation of bothe the cell mediated and humoral immunity?
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Helper T cells
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33) Type of cells that can activate B lymphocytes and cytotoxic T lymphocytes by bringing them antigen fragments?
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APCs
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34) Type of cell mediated cell that forms clones for future exposure to antigens?
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memory T cells
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35) Type of lymphocytes that can limit the attack of the immune system by releasing inhibiting lymphokines?
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suppressor T cells
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36) Type of self antigen found on macrophaes and other APCs?
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MHC-2
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37) Type of self antigen found on all nucleated cells?
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MHC-1
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38) Type of MHC antigen that is recognized by CD4 receptors
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MHC-2
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39) Type of lymphocyte that has CD8 receptors?
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Killer T cells
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40) Costimulator provided by macrophages to helper T cells?
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Interleukin I
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41) Costimulator provided by macrophages to helper T cell?
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Interleukin II
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42) Function of lymphotoxins produced by the killer T cell?
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Shreds DNA
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43) Chemical released by killer T cell that punch holes in virally infected cell?
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perforin
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45) Type of T cell that slow down the immune response?
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suppressor T cells
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44) Factor produced by killer T cells that destroys cells infected by cancer?
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Tumor necrocis factor
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46) Type of immunity that is transmitted from mother to fetus?
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Natural passive
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47) Type of immunity that is developed from a vaccination?
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Artifical active
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48) Type of immunity developed after having a disease?
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Natural active
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49) Factor released by killer T cells that attract macrophages to the area of attack?
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MIF/MAF
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50) Type of antibody invilved in the agglutination of red blood cells ?
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IgM
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51) Enzyme used by retroviruses to plant genetic material of the virus into the host's genome?
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reverse transcriptase
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Blood normally flow into a capillary bed from?
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a metarteriole
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Plasma solutes enter the tissue fluid most easily?
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fenestrated capillaries
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A blood vessel adapted to withstand a high pulse pressure would b expected to have?
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an elastic tunica media
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The substance most likely to cause a rapid drop in blood pressure is?
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histamine
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A person with a systolic blood presssure of 130 mm Hg and a diastolic pressure of 85 mm Hg would have a mean arterial presure of about?
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100 mm Hg
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The velocity of blood flow decreases if?
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viscosity increases
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Blood flows faster in a venule than in a capillary because venules?
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have larger diameters
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In a case where interstitial hydrostatic pressure is negative, the only force causing capillaries to reabsorb fluid is?
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colloid osmotic pressure of the tissue fluid
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Intestinal blood flow to the liver by way of?
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the hepatic portal system
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The brain receives blood from all of the following vessels except the ____artery or vein?
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internal jugular
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The highes arterial blood pressure attained during ventricular contraction is called ____pressure. The lowest attained during ventricular relaxation is called_____pressure?
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systolic, diostolic
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The capillaries of skeletal muscles are of the structural type called?
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continous capillaries
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_____shock occurs as a result of exposure to an antigen to which one is hypersensitive
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anaphylactic
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The role of breathing in venous reture is called the ____?
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thoracic
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The difference between teh colloid osmotic pressure of blood and that of the tissue fluid is called ___?
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oncotic pressure
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Movement accross the capillary endothelium by the uptake and release of fluid droplets is called ?
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trancytosis
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All efferent fibers of the vasomotor center belong to the _____division of the autonomic nervous system?
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sympathetic
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The pressure sensors in the major arteries near the head are called?
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baroreceptors
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Most of the blood supply to the brain comes from a ring of arterial anastomoses called ?
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the arterial circle
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The major superficial veins of the arm are the ____on the medial side and ______on the laterial side
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basilic, cephalic
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In some circulatory pathyways, blood can get from an artery to a vein without going through capillaries.
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In some cases, a blood cell may pass through two capillary beds in a single trip from left ventricle to right atrium
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the body's longest blood vessel is the great saphenous vein.
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The femoral triangle is bordered by the inguinal ligament, satorius muscle, and adductor longus muscle.
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The lungs receive both pulmonary and systemic blood.
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Some veins have valves, but arteries do not.
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By the formula Foc r4, the low increases 16-fold
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the capillaries normally reabsorb about 85% of the fluid they filter; the rest is absorbed by the lymphatic system.
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An aneurysm is a weak, bulging vessel that may rupture.
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Anaphaylactic shock is a form of venous pooling shock.
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The only lymphatic organ with both afferent and efferent lymphatic vessels is?
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a lymph node
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Which of the following cells are involved in nonspecific resistance but not in specific defense?
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(natural killer cells)
are involved are helper T cells, cytotoxic T cells, B cells, plasma cells |
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the respiratory burst is used by ____ to kill bacteria.
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neutrophils
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Which of these is a macrophage?
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a microglial cell
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The cytolytic action of the complement system is most similar to the action of?
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perforin
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____ become antigenic by binding to larger host molecules.
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Heptens
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Which of the following correctly states the order of event in humoral immunity? Let 1 = antigen display, 2 = antibody secretion, 3 = secretion of interleukin, 4 = clonal selection. and 5 = endocytosis of an antigen.
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5-1-3-4-2
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The cardinal signs of inflammation include all of the following except.
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fever
(include-swelling, heat, redness, pain) |
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A helper T cell can bind only to another cell that has
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MHC-II proteins
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Which of the following results from a lack of self-tolerance?
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systemic lupus erythematosus
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Any organism or substance capable of causing disease is called a/an
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pathogen
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Muccous membranes contain an antibacterial enzyme called?
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lysozome
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____ is a condition in which one or more lymph nodes are swollen and painfule to the touch
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lymphademitis
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The movement of leukocytes through the capillary wall is called
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diapedesis
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In the process_____, complement proteins coat bacteria and serve as a binding site for phogocytes.
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opsonization
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Any substance that triggers a fever is called a/an ?
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pyrogen
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The chemical signals produced by leukocytes to stimulate other leukocytes are called___?
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interleukins
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Part of an antibody called the ____ binds to part of an antigen called the ____.
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antigen bindind site, eptiope
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Self-tolerance results from a processed called ____, in which lymphocytes programmed to react against sefl-antigens die.
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clonal deletion
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Any disease in which antibodies attack one's own tissues is called a/an _____ disease.
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autoimmune
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T lymphocytes undergo clonal deletion and anergy in the thymus.
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The white pulp of the spleen gets its color mainly from lymphocytes and macrophages.
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Perforins are employed in both nonspecific resistance and cellular immunity.
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histamine and heparin are secreted by basophils and mast cells.
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A person who is HIV-positive and has a T H (CD4) of 1,000 cells/micro liter does not have AIDS
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Lysoozyme is a bacteris-killin enzyme
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Interferons promote inflammation
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Helper T cells are also necessary to humoral immunity
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anergy is a loss of lymphocyte activity, whereas autoimmune disease result from misdirected activity
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Interferons inhibit viral replication; perforins lyse bacteria
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Blood Vessels and Circulation
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Most common route: heart arteries arterioles capillaries venules veins
Portal system -blood flows through two consecutive capillary networks before returning to heart hypothalamus--anterior pituitary found in kidneys between intestines-liver |
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Circulation Routes: Anastomes
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Arteriovenous shunt
-artery directly to vein -fingers, toes, ears; decrease heat loss, allows blood to bypass exposed areas during cold Venous anastomosis -more common -alternate drainage of organs Arterial anastomosis -collateral circulation |
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The Vessel Wall
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Tunica externa
-outermost layer -loose connective tissue Tunica media -middle layer -usually thickest; smooth muscle, collagen, some elastic -smooth muscle for vasoconstriction and vasodilation Tunica interna -inner layer, exposed to blood -simple squamous endothelium |
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Arteries
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conducting (elastic) arteries)-largest
-pulmonary aorta and common carotid -tunica media consists of perforated sheet of elastic tissue, alternating with thin layers of smooth muscle, collagen and elastic fibers -expand during systole, recoil during diastole; lessens fluctuations in BP Distributing (muscular) arteries -distributes blood to specific organs; femoral and splenic -smooth muscle layers constitues 3/4 of wall thickness |
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Arteries adn metarterioles
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Resistance (small) arteries
-arterioles control amount of blood to various organs Metarterioles -short vessels connect arterioles to capillary -muscle cells form a procapillary sphincter about entrance to capillary |
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Small Vessels
capillaries |
Through fare channel- metarteriole continues through capillary bed to venule
Precapillary sphincters control which beds are well perfused -only 1/4 of capillaries are open at a given time |
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Types of capillaries
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continous-occure in most tissue
-endothelial cells have tight junctions with intercellular clefts (allow passage of solutes) Fenestrated- kidnesy, small intestine -organs that requirerapid absorptionor filtration; -endothelial cells have filtration pores (fenestrations) - allow passage of small molecules sinusoids- liver, bone marrow, spleen -irregular blood- filled spaces; some have extra lage fenestrations, allow proteins and blood cells to enter |
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Veins
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Venules
-proximal venule is quite porous, exchanges fluid with tissue, like a capillary, at this point only Venous sinuses: veins with thin walls, large lumens, no smooth muscle Veins have lower blood pressure: ave 10mmHg with little fluctuation -thinner walls, less muscular and elastic tissue -veins expand easily, have high capacitance -venous valves aid skeletal muscle in upward blood flow |
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Principles of Blood flow
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Blood flow: amount of blood flowing through a tissue in a given time (mL/min)
Perfusion: rate of blood flow per given mass of tissue (mL/min/g) Important for delivery of nutrients and oxygen, and removal of metabolic wastes Hemodynamics: physical principles of blood flow based on pressure and resistance -F oc ^P/R, (F = flow, ^ P = difference in pressure R = resistance to flow) R-decrease flow |
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Blood Pressure
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Measured at brachial artery of arm
systolic pressure: BP during ventricular systole diastolic pressur: BP during ventricular diastole Normal value, young adult: 120/75 mmHg Pulse pressure: systolic-diastolic -important measure of stress exerted on small arteries Mean arterial presure (MAP): -measurements taken at intervals of cardisc cycle, best estimate: diastolic pressure + (1/3 of pulse pressure) -varies with gravity: standing; 62-head, 180-ankle |
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Abnormaliteis of Blood Pressure
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Hypertension
-chronic resting BP>140/90 -can weaken small arteries and cause aneurysms Hypotension -chronic low resting BP -causes: blood loss, dehydration, anemia |
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Blood Pressure 2
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Importance of arterial elasticity
-expansion and recoil maintains steady flow of blood throughout cardiac cycle, smoothes out pressure fluctuations and decrease stress on small arteries BP rises with age: arteries less distensible BP determined by cardias output, blood volume, and peripheral resistance |
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Peripheral Resistance
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Blood viscosity - by RBC's and albumin
-decrease viscosity with anemia, hypoproteinemia -increase viscosity with polycythemia, dehydration Vessel length -pressure and flow decline with distance Vessel radius - very powerful influence over flow -most adjustable variable, controls resistance quickly -vasomotion: change in vessel radius =vasocontriction, vasodilation |
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Peripheral resistance (cont)
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-laminar flow- flos in layers, faster in center
- blood flow (F) proportional to teh fourth power of radius (r), F oc r4 arteriole can constrict to 1/3 of fully relaxed radius if r = 3 mm, F = (3 to the 4 power) = 81 mm/sec; if r = 1 mm, F = 1 mm/sec |
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Flow at different points
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From aorta to capillaries, flow decreases for 3 reasons:
1. greater distance traveled, more friction to decrease flow 2. smaller radii of arterioles and capillaries 3. farther from heart, greater the total cross sectional area From capillaries to vena cava, flow decrease again -large amount of blood forced into smaller channels -never regains velocity of large arteries |
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Reglulation of BP and Flow
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- local control
-Neural control -Hormonal control |
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Local control of BP adn Flow
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Metabolic theory
-tissue inadequately perfused, wates accumulate = vasodilation Vasoactive chemicals -substance that stimulate vasomotion; histamine bradykinin Reactive hyperemia -blood supply cut off then restored Angiogenesis- growth of new vessels -regrowth of uterine lining, around obstructions, exercise, malignant tumors -controlled by growth factors and inhibitors |
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Neural Control of BP and Flow
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Vasomotor center of medulla oblongata
-sympathetic control stimulates most vessels to constrict, but dilates vessels in skeletal and cardiac muscle -integrates three autonomic reflexes 1. baroreflexes 2. chemoreflexes 3. medullary ischemic reflex |
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Neural Control: Baroreflex
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Changes in BP detected by stretch receptors, baroreceptors in large arteries above heart
-aortic arch -aortic sinuses (behind aortic valve cusps) -carotid sinus (base of each internal carotid artery) Autonomic negative feedback response -baroreceptors send constant signal to brainstem -increased BP causes rate of signal to rise, inhibits vaso motor, decrease sympathetic tone, vasodilation causes BP to decrease ----- decreased BP causes rate of signal to drop, ______, increased sympathetic tone, vasocostriction and BP increase |
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Neural Control : Chemoreflex
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Chemoreceptors in aortic body and carotid bodies
-located in aortic arch, subclavian arteries, external carotid arteries Autonomic response to change in blood chemistry -pH, O2, CO2 -primary role: adjust respiration -secondary role: vasomotion hypoxemia, hypercapnia and acidosis stimulate chemoreceptors, instruct vasomotor center to cause vasoconstriction, increased BP, increased lung perfusion, and gas exchange |
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Chemoreceptors and other Inputs to Vasomotor Center
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Medullary ischemic reflex
-inadequate perfusion of brainstem cardiac and vasomotor centers send sympathetic signals to heart and blood vessels: increase cardiac output and increase BP Other brain centers -stress, anger, arousal can also increase increase BP |
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Hormonal Control of BP and flow Angiotensin II
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Angiotensinogen (prochormone produced by liver)
-decrease Renis 9kidney enzyme - low BP Angiotensin I - decrease ACE (angiotensin-converting enzyme in lungs) Angiotensin II -very potent vasoconstrictor |
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Hormonal Control of BP and Flow 2
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epinephrine and norepinephrine effects
-most blood vessels binds to alpha-adrenergic receptors, vasoconstriction -skeletal and cardiac muscle blood vesels binds to beta-adrenergic receptors, vasodilation ADH (water retention) -pathologically high concentrations, vasoconstriction Atrial natriuretic factor (increase urinary sodium excretion) -generalized vasodilation |
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Routing of Blood flow
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Localized vasoconstriction
- pressure downstream drops, pressure upstream rises -enables routing blood to different organs as needed arterioles - most control over peripheral resistance - located on proximal of capillary beds - most numerous - more muscular by diameter |
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Blood Flow in response to Needs
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Arteriorles shift blood flow with changing priorities
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Blood Flow comparison
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During exercise
- increased perfusion of lungs, myocardium and skeletal muscles decrease perfusion of kidneys and digestive tract |
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Capillary Exchange
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Only occurs across capillary walls between blood and surrounding tissues
3 routes across endothelial cells - intercellular clefts - fenestrations - through cytoplasm mechanisms involved - diffusion, transcytosis, filtration and reabsorption |
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Capillary Exchange- Diffusion
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Most importand mechanism of exchange
Lipid soluble substances - steroid hormo nes, O2, CO2 diffuse easily Insoluble substances - glucose and electrolytes mus pass through channels, fenestrations, intercellular clefts Large particles - proteins, held back |
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Capillary Exchange -Transcytosis
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Pinocytosis, transport vesicles across the cell, exocytosis
Important for fatty acids, albumin and some hormones (insulin) |
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Filtration adn Reabsorption
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Opposing forces
- blood hydrostatic pressure drives fluid out of capillary high on arterial end of capillary, low on venous end - Colloid osmotic pressure draws fluid into capillary ( same on both ends) results from plasma proteins (albumin) - more in blood oncotic pressure = net COP (blood COP- tissue COP) |
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Capillary Filtration and Reabsorption
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Capillary filtration at arterial end
Capillary reabsorption at venous end Variations -location 9glomeruli-filter, alveolar cap. - absorb) -activity, trauma ( increase filtration) |
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Causes of Edema
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increase capillary filtration ( increase capillary BP or permeability)
- poor venous return congestive heart failure - pulonary edema insufficient muscular activity - kidney failure (water retention, hypertension) -histamine make capillaries more permeable decrease capillary reabsorption - hypoproteinemia (oncotic pressure oc blood albumin ) cirrhosis, famine, burns, kidney disease) Obstructed lymphatic drainage (due to removal also) |
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Consequences of Edema
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Circulatory shock
- excess fluid in tissue spaces causes low blood volume and low BP Tissue necrosis - oxygen delivery and waste removal impaired pulmonary edema - suffocation Cerebral edema - headaches, nausea, seizures and coma |
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mechanisms of Venous Return- Blood flow back from the heart
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pressure gradient
-- 7-13 mm Hg venous pressure towards heart venules ( 12-18 mm Hg) to central venous pressre ( about 5 mm Hg) Thoracic pump - inhalation - thoracic cavity expands ( presure decrease) abdominal pressure increases, forcing blood upward - cnetral venous pressure fluctuates 2 mm Hg - inhalation, 6 mm hg - exhalation blood flow faster with inhalation Skeletal muscle pump in the limbs Gravity drains blood from head and neck |
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Venous Return and phsical Activity
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Exercise- increases venous returen in many ways
- heart beats faster, harder - increase CO and BP - vessels of skeletal muscle, lungs and heart dialate increase flow - increase respiratory rate increase action of thoracic pump - increase skeletal muscle pump Venous pooling occurs with inactivity - venous pressure not enough force blood upward - with prolonged standing, CO may be low enough to cause dizziness or syncope -- prevented by tensing leg muscle, activate skeletal muscle pump |
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Circulatory Shock
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Any state where cardiac output insufficient to meet metabolic needs
- cardiogenic shock - inadequate pumping of heart (MI) - low venous return (LVR) shock - 3 principle forms LVR shock - loss of blood volume: tauma, bleeding, burns, dehydration - obstructed venous return shock - tumor or aneurysm 1. Venous pooling (vascular) shock - long periods of standing, sitting or widespread vasodilation - neurogenic shock - loss of vasomotor tone, vasodilation causes from emotional shock to brainstem injury 2. Septic Shock - bacterial toxins trigger vasodilation and increase capillary permeability 3. Anaphylactic shock - severe immune reaction to antigen, histamine release, generalized vasodilation, increase capillary permeability |
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Responses to Shock
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Compensated Shock-
- homeostatic mechanixms may bring about recovery - decrease BP triggers baroreflex and production of angiotensin II, both stimulate vasoconstriction - if person faints and falls to horizontal position, gravity restores blood flow to brain; quicker if feet are raised Decompensated Shock (above mechanisms fail) (life threatening positive feedback loops occur) - decrease COmyocardial ischemia and infarction decrease CO - slow circulation disseminated intravascular coagulation slow circulation - ischemia and acidosis of brainstem decrease vasomotor toen, vasodilation decrease CO ischemia adn acidosis of brainstem |
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Special Circulatory Routes- Brain
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Total perfusion kept constant
- few seconds of deprivation causes loss of consciousness - 4-5 minutes causes irreversible brain damaeg - flow can be shifted from one active region to another Responds to changes in BP and chemistry CO 2 + H2O H2 + (HCO3)- if CO2 increases (hypercapnia) in brain, pH decreases, vasoconstriction, occurs with hyperventilation, may lead to ischemia, dissiness and sometimes syncope. |
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TIA's and CVA's
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TIA's- transient ischemic attack
- dizziness, loss of vision, weakness, paralysis, headache or aphasia; lasts from a moment to a few hours oftern early warning of impending stroke CVA- cerbral vascular accident (stroke) - brain infarction caused by ischemia atherosclerosis, thrombosis, ruptured aneurysm -effectsrange from unnoticeable to fatal blindness, parylysis, loss of sensation, loss of speech common - recovery depends on surrounding neurons, collateral circulation |
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Skeletal Muscle
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Highly varialbe flow
At rest - arterioles constrict, total flw about 1L/min During exercise - arterioles dilate in response to epinephrine and sympathetic nerves - precapillary sphincters dilate due to lactic acid, CO2 - blood flow can increase 20 fold Muscular contraction impedes flow - isometric contraction causes fatigue faster than isotonic |
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Special Circulatory routes- Lungs
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Low pulmonary blood pressure
- flow slower, more time for gas exchange - capillary fluid absorption oncotic pressure overrides hydrostatic pressure Unique response to hypoxia - pulmonary arteries constrict, redirects flow to better ventilated region |
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Pulmonary circulation
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Pulmonary trunk to pulmonary arteries to each lung
- lobar branches for each lobe (3 right , 2 left) Pulmonary veins returen to left atrium - increased O2 and reduced CO2 levels |
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Pulmonary capillaries near Alveoli
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- Basketlike capillary beds suround the alveoi
- Exchange of gases with air at alveoli |
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Major Systemic Arteries
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Supplies oxygen and nutrients to all organs.
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Lymphatic System
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Absorbs 1/4 to 1/2 of plasma protein and tisue fluid ( 2 to 4 L/day), returns it to the bloodstream
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Lymph and Lymphatic Capillaries
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Lymph- clear, colorless fluid, similar to plasma but contains much less protein
Lymph capillaries- closed at one end - tethered to surrounding tissue by protein filaments - endothelial cells loosely overlapped - allow bacteria and cells entrance to lymphatic capillary - creates valve-like flaps that open when interstitial fluid pressure is high, and close when it's low |
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lymphatic vessles
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Larger ones composed of 3 layers
1. tunica interna; endothelium and valves 2. tunica media: elastic fibers, smooth muscle 3. tunica externa: thin outer layer Walls are thinner and valves are closer together than those of veins |
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Route of Lymph Flow
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Lymphatic capillaries (terminal lymphatics)
collecting vessels: course through many lymph nodes- travel along arteries and veins- bacteria are phagocytized, immune cells monitor fluid for foreign antibodies Collecting ducts: lymphatic trunks converge to form two collecting ducts right lymphatic duct - union of right jugular, subclavian and brochomediastinal lymphatic trunks thoracic duct - on left side larger adn longer, gegins as a prominent sac in abdomen called the cisterna chyli, receives lymph from below diaphragm, left arm, left side of head, neck and thorax each collecting duct drains into a subclavian vein--- most through into the left subclavian vein. |
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Mechanisms of Lymph Flow
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Lymph flow at low pressur and speed
Valves prevent backward flow Moved along primarly by rhythmic contractions of lymphatic vessels - stretching of vessels stimulates contraction Flow aided by skeletal muscle pump Thoracic pump aids flow from abdominal to thoracic cavity Rapidly flowing bloodstream in subclavian veins, draws lymph ito it. Exercise significantly increases lymphatic return |
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Lymphatic Tissue
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Diffuse lymphatic tissue: lymphocytes in mucous membranes adn CT of many organs
Mucosa- associated lymphatic tissue: (MALT)particularly prevalent in pas sages open to the exterior Lymphtic nodules: dense oval masses of lymphocytes, congregate in response to pathogens, constant in Peyer patches: Peyer patches: more permanent congregation, clusters found at junction of small to large intestine |
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Lymph Node
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Lymph nodes are only organs that filter lymph
- fewer efferent vessels, slows flow through node - riticular cells, macrophages phagocytize foreign matter -lymphocytes respond to antigens - common sites for metastatic cancer - Corte gives off trabeculae, divide parenchyma into compartment containing stroma (reticular CT) and parenchyma 9 lymphocytes adn macrophages) subdivided into cortex 9 lymphatic nodules) and medulla |
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Tonsil
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-covered by epithelium
-pathogens get into crypts and encounter lymphocytes Location: -Palatine tonsils: pair at the posterior margin of oral cavity; most often infected -Lingual tonsils: pair at the root of tongue - Pharyngeal tonsils: single tonsil on wall of pharynx |
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Thymus
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contains developing lymphocytes, secretes hormones (thymopoietin and thymosins) to regulate their later activity
-Very large in fetus, after age 14 begins involution (shrinkage) and in elderly mostly composed of fatty and fibrous tissue - Involved in maturation ofT Cell lymphocytes |
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Spleen
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-inferior to diaphragm, dorsal to stomach
-parenchym appears in fresh specimens as -red pulp: sinuses filled with erythrocytes - white pulp lymphocytes, macrophages; surrounds small branches of splenic artery Functions: - blood production in fetus -blood reservior -RBC disposal -immune reactions: only lymphatic organ that filters blood, quick to detect antigen |
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Defenses Against Pathogens
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Part 1: Nonspecific defenses- broadly effective, no prior exposure
- external barriers: skin and muscous membranes - inflammation, fever (leukocytes, macrophages, antimicrobial proteins, immune serveillance) Part II: Specific defense- results from prior exposure, protects against only a particular pathogen (leaves "memory" of it so next time it can be defeated sooner when infected again) - immune system- provides future protection only against that particular pathogen. |
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Part I: NonSpecific Defenses
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-Barriers
-Leukocytes -Inflammatory Response -Inflammatory Chemicals -Leukocyte mobilization -Leukocyte Actions -Tissue repair -Antimicrobial Proteins -Fever |
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External Barriors
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Skin
- keratin is tough and impermeable- only a few pathogen can penetrate - dry and nutrien-pooe - lactic acid (acid mantle) is a component of perspiration- antimicrobials chemicals inhibits growth mucous membranes - mucus provides sticky entrapment of microbes - lysozyme: enzyme destroys bacterial cell walls - subepithelial areolar tissue tissue gel: viscous barrier of hyaluronic acid- difficultfor microbes to migrate through Lyaluronidase: enzyme used by pathogens to loosen gel to a thinner consistency for easier migration |
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Leukocytes in Non Specific Defense
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neurtophils
- phagocytize bacteria - create a killing zone - degranulation: lysosome discharge into tissue fluid, triggers -Respiratory burst: toxic chemicals are created (O2, H2O2, HClO) Neurphils, bacteria and surrounding tissues are destroyed Eosinophils- Found in the mucous membrane - phagocytize antigen-antibody complexes (bullet) allergens, inflammatory chemicals - antiparasite effects against worm: aggregate adn release enzymes, release chemical toxins, promotes the actions of basophils adn mast cells |
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Leukocytes
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Basophils:
-aid mobility and action ofWBC's by teh release of --histamine (vasodilator) increase blood flow to infected tissue to increase delivery of leukocytes --heparin (anticoagulant) prevents immobilzation of phagocytes - inflammatory response Lymphocytes (T adn B cells) -natural killer (NK) cells, nonspecific defense, large cells lyse host cells infected with viruses or cancerous Monocytes: circulating precursors to macrophages |
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Inflammation
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Cardinal signs of inflammation
- redness (erythema) caused by hyperemia ( increase blood flow) - swelling 9edema) caused by increased capillary permeability and filtration - heat caused by hyperemia - pain caused by inflammatory chemical (bradykinin, prostaglandins) secreted by damage cells, pressure on nerves) |
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Inflammation Response
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Defensive response to tissue injury
-caused by Chemicals released by WBCs and tissue - limit spread of pathogens, then destroys them; removes debris, initiates tissue repair - suffix -itis denotes inflammation of specific organs |
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Inflammatory Chemicals
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-Bradykinin, Histamine, and Leukotrienes
Secreted by damaged cells, mast cells, basophils, lymphocytes, macrophages, platelets - Stimulates vasodilation that leads to hyperemia - redness and heat: increase local metabolic rate, promotes cell multiplication adn healing - dilutes toxins, provides o@, nutrients, waste removal - increase permeability of blood capillaries - allows blood cells, plasma chemicals 9antibodies, complement proteins, fibriogen) into tissue - clotting sequesters bacteria, forms scaffold for tissue repair - swelling the decrease venous flow, increase lymphatic flow that favors removal of bacteria and debris |
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Leukocyte mobilization
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Margination: leukocytes adhere to blood vessel wally (cell adhesion molecules)
Diapedesis (emigration): leukocytes squeeze between endothelial cells into tissue space Chemotaxis: leukocytes are attracted to inflammatory chemicals Phagocytosis: 1st Neutrophils then Macrophages |
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Leukocyte Activity
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Damaged tissues release factors causing:
- neutrophils to be rapidly produced and released - basophils to release inflammatory chemicals - eosinoophils attraction in cases of parasitism and allergy -monocytes to arrive in 8 to 12 hours, become macrophages, the primary agent of cleanup Formation of pus - mixture of tissue fluid, cellular debris, dying neutrophils and microbes. |
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Tissue Repair
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-Endothelial cells and platelets secrete platelet derived growth factor (PDGF)
-PDGF stimulates fibroblasts to multiply and synthesize collagen fibers and matrix -some tissues cannot be replaced, then fibroblasts form scar tissue. |
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Antimicrobial Interferons
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Interferons: polypeptides secreted by cells invaded by viruses
- antiviral effect - generalized protection - interferons diffuse to neighboring cells and stimulate them to produce antiviral proteins - activate natural killer cells and macrophages - distroy infected host cells - anticancer effect - stimulate destruction of cancer cells |
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Antimicrobial Proteins: Complement System
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- Group of proteins in blood that must be activated by pathogens to exert their effect
- pathways of complement activations - "classical pathway" Antigen-antibody complex - "alternate pathway" from Raw antigen - mechanisms of action - Enhanced inflammaion-enhanced (stimulates release of inflammatory chemicals) - opsonization (promotes phagocytosis) - cytolysis- MAC attack Cytolysis) Membran attack Complex |
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Mac Attack
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Complement proteins C5b to C9 form ring in plasma membrane of enemy cell cauing cytolysis
-causes cell to spew out it guts |
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Fever
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Defense mechanism: can do more good than harm
- promotes interferon activity - accelerating metabolic rate and tissue repair - inhibiting pathogen reproduction Pyrogen: secreted by macrophages, stimulates anterior hypothalamus to secrete PGE which resets body thermostat higher- 102 F > 105 F may cause delirium, 111 F-115 F, coma-death -Stages of fever- onset, stadium, defervescence |
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Specific immunity
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Specificity and memory
1. Cellular Immunity: cell- mediated response to infected or cancerous cells 2. humoral Immunity: antibody mediated- blood antibodies |
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Specific Immunity
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-antigens
-antibodies -cells of specific immune response -chemicals of specific immunity -MHC self recognition proteins |
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Antigens
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Antigens- "Foreign Molecules
-trigger an immune response -comples molecules> usually protein, unique to each individual - sometimes polysaccharides or nucleic acids -Antigenic determinants- part of molecule that is recognized as foreign and can stimulate an immune response - Hapens: Molecules to small to cause reaction until they bind host macromolecule adn stimulate immune response |
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Antigenic Determinants
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- Molecules produced by Lymphocytes (B Cell) that will attack teh antigens
-Very specific for antigen surface -Have AntigenBinding Regions and Constant Regions - Two heavy and two light chains in a "Y" shape |
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5 Antibody Classes
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C region determines class by amino acid sequences
1. IgA: monomer in plasma; dimer in Mucus, saliva tears, milk, intestinal secretions, prevents adherence to epithelia 2. IgD: monomer; B cell membrane, antigen receptor 3. IgE: monomer; tonsils, skin, mucous membranes; stimulates release of histamine, attracts eosinophils 4. IgG: monomer; 75%-85% circulating, crosses placenta to fetus, secondary immune response, binds complement 5. IgM: monomer; B cell membrane, antigen receptor; pentamer in plasmsa, 1ST immune response, agglutination |
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Antibody Diversity
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immune system produces as many at 2 million different antibodies
-Somatic recombination- DNA segments shuffled and form new combinations of base swquences to produce antibody genes |
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Specific Immunity Cells
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-Lymphocytes
-Helper T cells coordinate both celland humoral immunities- turn systems on -killer T cells attack infected body cells -Suppressor T cells help turn response off -B cell lymphocytes of humoral response make antibodies |
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T lymphocytes (T cells) and their two type of receptors
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-Stem cells from fetus bone marrow migrate to thymus for 2-3 days for indoctrination
-Thymosins- sitimulate these T cells to produce 10,00= 100,000 plasma membrane proteins, antigen receptor ro T cell receptors -Once the TCRs are in place it is considered an immune competent : cell -Clonal deletion: destruction of any T cell in fetus capable of responding to self-antigens, leaves the body in a state of self-tolerance - In addition, T cells must have either CD4 or CD8 receptors that can recognize teh bodies cells - Once mature if a T cell is exposed to it specific antigen, that T cell will divide rapidly, forms a clone of T cells with identical receptors |
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B Lymphocytes (B cells)
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-sites of developement
- fetal stem cells from liver, bone marrow and intestine submucosa develop specific receptors -B cell clones are formed when exposed to antige -synthesiz antigen receptors, divide rapidly, produce immunocompetent clones -clones produce and release free receptors into blood called antibodies -Form 20- 30% of lymphocytes of the blood |
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APCs = Antigen Presenting Cells
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- the immune response Cells will not react to antigens unless they are formally "presented" to them.
The Antigens presenting cells include: 1. macrophages 2. Dendritic cells 3. B cells can act as APCs These APCs will engulf and process antigen by mixing it up with its MHC II proteins and presenting it to a Helper T cells |
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Antigen-Presenting cells (APCs)
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B cells and macrophages, display antigent to T cells.
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Interleukins
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-Hormone like messengers between leukocytes
-Lymphokines: produced by lymphocytes -Monokines: produced by macrophages- monocytes are macrophage precursors) |
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MHC self recognition proteins
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-major Tissue histocompatibility proteins
-MHC I on all nucleated cells All cells except RBCs -will bind to DC8 receptors of killer T cells -MHCII on APCs Allow recognition that they are allowed t present antigens -will bind to CD4 receptor on Helper T cell |
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CD recognition
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- MHC restriction
- T cells in Thymus will develop either CD4 or CD8 receptors - Helper T cells have CD4 receptors -CD4 receptors can "dock with" MCHII receptors of APCs - Cytotoxic Cells (killer T cells) have CD8 receptors that can "dock with" MHCII proteins |
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CD and TCR
doulble recognition |
- An APC digest and presents an antigen to the helper T (helper) cell with an antigen (T antigen receptor) specific for that antigen
- simultaneously, the CD4 receptor of the Helper T docks with the MHCII protein of the APC -This activates the helper T but it needs CD stimulation from the macrophage (APC) - interlukin I is the costimulator |
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Double recogination
Activation of Killer T cells |
-killer T has TCR that binds specific antigen on surface of infected body cell
-Killer T has CD8 receptor that will also bind to MHCI of infected cell -Double Recognition is made and then we need Costimulation |
