Exam 3 Study Guide PET3323 Lymphatic System 1 Be able to explain the main role of lymph nutrients waste what makes it etc The lymphatic system is an elaborate system of drainage vessels that collect the excess protein containing interstitial fluid and return it to the bloodstream Once interstitial fluid fluid enters the lymphatics it is called lymph 2 Know how lymph drains throughout the body structural anatomy of the lymph capillaries A The endothelial cells forming the walls of the lymphatic capillaries are not tightly joined Edges of adjacent cells overlap each other loosely creating flap like mini valves B Collagen filaments anchor the cells to surrounding structures so that an increase in interstitial fluid volume opens the mini valves instead of them collapsing Exam 3 Study Guide PET3323 3 Know how lymph drains throughout the body structural anatomy of the lymph capillaries This transport system begins in microscopic blind ended lymphatic capillaries that weave between the tissue cells and blood capillaries in the loose connective tissues of the body lacteals are highly specialized lymph capillaries present in the fingerlike villi of the intestinal mucosa This lymph is cloudy instead of clear because of its role in absorbing digested fats from the intestine and is called chyle 4 Know the order of the of the lymphatic circulatory vessels e g capillaries collecting vessels lymphatic trunks lymphatic ducts which regions of the body drained by the ducts and where the ducts empty the lymph fluid back into the blood circulatory system Successively the channels become larger and larger lymphatic collecting vessels have the same 3 tunics as veins but have thinner walls more internal valves and vary greatly from individual to individual lymphatic trunks are formed by the union of the largest collection vessels and drain large regions of the body for which they are named paired lumbar and bronchomediastinal subclavian and jugular intestinal trunk single unpaired Right lymphatic duct drains lymph from the right upper limb and the right side of the head and thorax Thoracic duct receives lymph from the rest of the body cisterna chyli is an enlarged sack at the 1st 2 lumbar vertebra that collects lymph from the 2 large lumbar trunks that drain the lower limbs and intestinal trunk Exam 3 Study Guide PET3323 5 Know the organs of the lymph system lymph nodes tonsils spleen and their roles Lymph Nodes have 2 basic functions as lymph is transported back to the blood stream the node acts as a filter Macrophages remove and destroy microorganisms and other debris preventing it from being delivered to the blood They help to activate the immune system Nodes are strategically placed where antigens are encountered so they can mount attacks Spleen provides a site for lymphocyte proliferation and immune surveillance and response The spleen also removes debris and foreign matter from the blood The spleen also stores some of the breakdown products of the red blood cells for later reuse stores blood platelets site of erythrocyte production in the fetus Thymus site where T lymphocytes become able to defend us against specific pathogens in the immune system Hassall s corpuscles are involved in the development of a class of T lymphocytes called regulatory T cells which are important for preventing autoimmune diseases Exam 3 Study Guide PET3323 Tonsils The tonsils are nt fully encapsulated and the epithelium overlaying them invaginates deep into their interior forming blind ended tonsillar crypts The crypts trap bacteria and particulate matter which makes it way inside where they are destroyed Peyers Patches aggravated lymphoid nodules large clusters of lymphoid follicles structurally similar to tonsils but located in the distal portion of the small intestine and the wall of the appendix They work to destroy bacteria before the pathogens breach the intestinal wall and to generate many memory lymphocytes for long term immunity Immune System 6 Know the major components of the immune system e g 1st 2nd and 3rd lines of defense Functional system made up of two intrinsic defense systems that act independently and cooperatively to provide resistance to disease Innate nonspecific Defense System Adaptive specific Defense System 1st and 2nd Lines of defense 3rd Line of defense Exam 3 Study Guide PET3323 7 Know the primary components of the 1st line of defense Surface barriers Skin and Mucosae Skin keratinized epithelial membrane Mucous membranes Resistant to most weak acids bases toxins Protective chemicals secreted 1 acidity of skin secretions pH 3 5 2 stomach mucosa secretes HCl and protein digesting enzymes 3 saliva and lacrimal fluid contain lysozymes Lysozyme found in saliva and the eyes destroys bacteria 4 mucus traps microorganisms 5 vagina secretions are low pH Lysozyme found in saliva and the eyes destroys bacteria Internal defenses Cells and Chemicals phagocytes macrophages and neutrophils white blood cells eat bacteria Natural Killer nk cells police the body in the lymph pitbulls of the defense system Inflammatory response prevents the spread of damage to nearby tissues disposes of cell debris and pathogens sets the area for repair Antimicrobial Proteins enhance the innate defenses by attacking microorganisms directly or by hindering their ability to reproduce interferons help protect cells that have not been infected Fever abnormally high body temp as a response to foreign invaders that is reset up by pyrogens that are secreted by macrophages exposed to foreign substances 8 Know the primary components of the 2nd line of defense i e nonspecific cellular and chemical defenses and their roles in immunity Adaptive defenses recognize and direct against specific pathogens or foreign substances that initiate the immune response Immunity is not restricted to the initial infection site After an initial exposure it recognizes and mounts a stronger attack on repeat offenders B Cells oversee humoral immunity antibodies present in the body s humors or fluids Exam 3 Study Guide PET3323 T cells non antibody producing lymphocytes that play auxiliary roles versus responding to specific antigens 9 Understand the basic process of phagocytosis Exam 3 Study Guide PET3323 10 Understand what triggers the inflammatory response and what causes each of the 4 cardinal signs of inflammation The 4 cardinal signs of Inflammation see the chart below for flow of response Redness Heat Swelling Pain Exam 3 Study Guide PET3323 11
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