Module 8: Lymphatic System & Immunity Exam with complete solutions

Module 8: Lymphatic System & Immunity Exam with complete solutions Interstitial Fluid - ANSWER-fluid that surrounds the cells of body tissues arises from blood plasma filtered through the capillary walls each day, 20L of fluid filter out of the blood capillary walls to form interstitial fluid but only 17L of interstitial fluid are reabsorbed at the venous ends of the capillaries. to maintain a constant blood volume, the remaining 3L must also re-enter the cardiovascular system through the lymphatic system Lymphatic System - ANSWER-a complex drainage system which carries excess interstitial fluid through its vessels, cleanses this fluid & empties it into the veins, where it again becomes part of the blood plasma Functions of the Lymphatic System - ANSWER-1. Drains excess interstitial fluid 2. Transports dietary lipids 3. Carries out immune responses Drains excess interstitial fluid - ANSWER-Lymphatic vessels drain excess interstitial fluid from tissue spaces & return it to the blood. Lymph - ANSWER-excess interstitial fluid that enters the lymphatic system & is emptied into the blood as plasma Transports dietary lipids - ANSWER-Lymphatic vessels transport lipids & lipid-soluble vitamins (A, D, E, & K) absorbed by the gastrointestinal tract Carries out immune responses - ANSWER-Lymphatic tissue initiates highly specific responses directed against certain pathogens & malignant or abnormal body cells. because of this function, the lymphatic system is sometimes referred to as the "immune system" Pathogen Pathogen - ANSWER-refers to any microorganism (bacteria, virus, etc.) capable of causing disease Structures of the Lymphatic System - ANSWER-1. Lymphatic capillaries 2. Lymphatic vessels 3. Lymphatic ducts 4. Thoracic duct 5. Right lymphatic duct Lymphatic capillaries - ANSWER-drain the interstitial spaces of excess fluid are located in spaces between cells unite to form larger lymphatic vessels passes its drained fluid, now called "lymph", to the lymphatic vessels Lacteals Lacteals - ANSWER-specialized lymph capillaries in the villi of the small intestine; they absorb the dietary lipids & lipid- soluble vitamins. Lymphatic vessels - ANSWER-receive the lymph passed on by the lymphatic capillaries & carry it away from the tissues resemble veins in structure but have thinner walls have more valves than veins to prevent backflow & ensure one-way flow of lymph lymphatic vessels pass lymph to one of two lymphatic ducts: (a) thoracic duct (b) right lymphatic duct