Lymphatic System Mastering A P homework 03 12 2014 The Lymphatic System lymphocytes essential to immune response bind antigens mostly occur in lymphoid tissues not in circulation occur as B T and NK types NOT phagocytic T cells o Approx 80 of circulating lymphocytes o Cytotoxic T Cells attack foreign cells or body cells infected by viruses o Helper T Cells o Suppressor T Cells o Memory T Cells Simulate activation function of both T cells and B cells Inhibit activation function of both T cells and B cells Respond to a previously encountered antigen B Cells o Approx 10 15 of circulating lymphocytes o Differentiate into plasma cells when stimulated Plasma cells produce secrete antibodies Natural Killer Cells o Approx 5 10 of circulating lymphocytes Lymphatic capillaries smallest vessels Lack a basement membrane Larger diameter than blood capillaries Have irregular profiles outline Endothelial cells overlap to act as a one way valve Allow free entry of viruses Start as pockets whereas blood capillaries are continuous tubes Lymphoid organs Thoracic duct Spleen thymus lymph nodes Receives lymph drained from entire body EXCEPT o Right arm upper right thoracic region this area receives lymph from right lymphatic duct instead BOTH lymphatic and blood capillaries Are composed of endothelium Nonspecific defenses block attack ANY potential infectious organism Interferons histamines neutrophils NOT immunoglobulins Group of proteins that work together binding to antibodies and Natural Killer NK cells type of lymphocyte Engage in immunological surveillance Kill cancer cells Hunt for tumor cells Complement pathway forming large holes in target cells Natural Killer Cell sequence 1 Recognition adhesion 2 Realignment of Golgi apparatus 3 Secretion of perforin 4 Lysis of abnormal cell Innate Defenses phagocytes engulf pathogens and cellular debris interferons coordination of defenses against viral infections Inflammatory response includes Increased capillary permeability Activation of phagocytes Clotting reaction walls off region Increased blood flow around injury site Properties of the immune response Triggered by an antigen May be antibody mediated Does not need to be acquired May be cell mediated Endogenous pyrogens Released by activated macrophages Cause fever hypothalamus raises body temp Forms of Immunity immunity that results from vaccination against influenza is classified as induced active Autoimmune illness results from a failure of what aspect of immunity Tolerance o Immune system ignores normal antigens self antigens The lymphocytes that enter tissues and directly attack antigens are Cytotoxic T cells o Specifically identify directly kill disease cells Class I MHC Displays antigens found in the cytoplasm of cells Found in membranes of all nucleated cells Which class of T lymphocyte is killed by the AIDS virus Helper T Steps in antigen presentation include Phagocytic antigen presenting cells engulf pathogens Antigen fragments appear on the antigen presenting cell s surface Antigens are digested Class II MHC proteins Found only on antigen presenting cells Present exogenous antigens antigens that originated from outside the cell phagocytized extracellular pathogens Class I MHC proteins Recognized by CD8 cells destined to become a T cell Which types of cells display protein fragments produced by the cancer within them All nucleated cells o Nucleated body cells bring pieces of endogenous proteins to the surface to display on the MHC protein Which major class of lymphocytes become cytotoxic T cells CD8 cells Steps in humoral immune defense The antigen specific helper T cells bind to sensitized B cells Helper T cells secrete cytokines The antigen binds specifically to B cell surface T cells DO NOT secrete immunoglobulins these are instead derived from plasma cells which come from B cells B Cells Sensitized by exposure to antigen Activated by helper T cells Capable of division IgE Classes of immunoglobulins Ig include G D E M A Antigen binds to Which class of immunoglobulins sensitizes cells to allergens Variable segment of each arm of an antibody molecule The class of antibody that produced first in the fetus at about 4 months of development is Changes in the immune system that accompany aging IgM Fewer helper T cells Fewer cytotoxic T cells T cells less responsive to antigens Thymic hormone production reduced Immune surveillance against tumor cells declines Ch 21 study module extra credit hw 03 12 2014 Blood passes from the left ventricle to the right atrium through the following in the order listed 1 Elastic artery 2 Muscular artery 3 Arteriole 4 Capillary 5 Venule 6 Vein Arteries have endothelium that appears pleated rippled Chemical gaseous exchange only takes place across capillary walls the pattern of blood flow through a capillary bed is influenced by sympathetic innervation only capillaries function as parts of a capillary plexus Tunica Externa Outer layer of blood vessel Connective tissue sheath Contains collagen fibers w scattered bands of elastic fibers in arteries Thicker than tunica media contains elastic fribers smooth muscle cells in veins Connective tissue fibers blend into adjacent tissues stablilization anchoring of blood vessel Tunica Media Middle layer of blood vessel Concentric sheets of smooth muscle tissue within loose connective tissue Bounded to tunica intima externa by collagen fibers Usually the thickest layer in a small artery External elastic membrane separates tunica media from surrounding tunica externa Smooth muscle cells encircle endothelium that lines the lumen of blood vessel o Smooth muscle contracts diameter of vessel decreases o Smooth muscle relaxes diameter of vessel increases Inner layer of blood vessel Endothelial lining surrounding layer of connective tissue w some Arteries outer margin contains thick layer of elastif fibers called elastic fibers internal elastic membrane Tunica Intima Interna Mean arterial pressure MAP diastolic pressure pulse pressure 3 Pulse pressure difference btwn systolic diastolic fenestrated capillaries are found in the choroid plexus kidneys The most important determinant in vascular resistance is friction between the blood and the vessel walls Amount of friction depends on vessel length diameter The two major factors affecting blood flow rates pressure resistance Arteries vs Veins the endothelial lining of an artery cannot contract when not opposed by blood pressure arterial walls contract arteries when stretched are more
View Full Document
Unlocking...