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Circulatory System Chapter 12 Structure & Function • Includes both lymph & blood • Both work to maintain homeostasis • Give the body immunity Blood • Hematology-study of blood • 5-6 liters of blood • More than 60,000 miles of vessels carry blood in the body • Makes up about 8% of body weight Formed Elements • Red blood cells • White blood cells • Platelets (thrombocytes) • Each drop of blood contains the following: – 5 million RBC’s – 10,000 WBC’s – 250,000 platelets Red Blood Cells • AKA-erythrocytes • 25 trillion RBC’s circulate • Each RBC lives 90-120 days • New cells made by red marrow or myeloid tissue in bones • Hemopoiesis is the process of making new red cells which a few million are made each second • Liver and spleen remove dead RBC’s and reuse the material Hemoglobin • Provides the RBC’s with red pigment • Heme-iron compound • Globin-protein molecule • Carry oxygen to the tissue • Single blood cell contains several molecules of hemoglobin White Blood Cells • • • • • AKA-leukocyte Fights disease & infections Larger than RBC’s Live about 9 days Can move out of blood vessels Types of WBC’s • Neutrophils-engulf & digest bacteria • Basophils-create anti-inflammatory response • Eosinophils-defend from allergic reactions • Lymphocytes-help produce antibodies • Monocytes-help remove foreign materials & bacteria Platelets • AKA-thrombocytes • Smallest blood cell • Promotes clotting to prevent blood loss • Live only 5-9 days Plasma • Pale yellow liquid left after formed elements removed from blood • Whole blood is 55% plasma • Contains 90% water & 10% proteins • Contains nutrients, electrolytes, oxygen, enzymes, hormones, & wastes • Helps fight infection & assist with clotting • Inherited characteristic Blood Typing • Type is determined by looking at specific antigens found on surface of RBC • Clumping of incompatible cells blocks the blood vessels and may cause death Blood Typing Group Antigen Marker Antibody Compatible Donor A A Anti-B A, O B B Anti-A B, O AB A, B None A, B, AB, O O None Anti-A Anti-B O • Four Types RH factor • Rh factor – Antigen – Found in the red blood cells – 85% of North Americans are Rhpositive RH-Factor • Giving Rh-positive blood to a person with Rh-negative blood can be fatal • Considered a foreign particle to the Rh person’s blood and tries to combat it by forming antibodies • Rh factor also important in Rh-negative mother having a second Rh-positive baby Blood Type O positive O negative A positive A negative B positive B negative AB positive AB negative Prevalence 38% 7% 34% 6% 9% 2% 3% 1% Lymph System Functions • Maintain body fluid balance • Helps with immunity Lymph System • Lymph is a watery substance formed from fluid that filters into the body tissue or interstitially • Works independently of circulatory system • Lymph tissue is more porous than capillaries which allows fats, proteins, & some cancer cells to be transported. • Lymph fluid only travels one direction which is toward the heart • Fluid is moved to the capillaries where is drained from lymphatic ducts into the blood • Circulates very slowly depends on muscle movement to circulate Lymphatic Tissues • consist of: – Tonsils • Found in back of throat – Thymus • Disintegrates after puberty – Spleen • Can store 1 pint of blood • Filters bacteria &foreign substances • Makes lymphocytes & monocytes – Nodes • Biological filters that remove bacteria & cancerous cells – Lymph vessels Immunity • Immune response takes on two forms: – Non-specific • As a barrier of the skin, mucous membranes, tears, and the leukocytes • In leukocytes, antibodies are formed in response to antigens or foreign materials that enter the body – May be a localized or systemic reaction Immunity • Specific Response – Acquired • Natural – Exposure to agent unintentionally » Babies being breastfed • Artificial – Exposure intentionally » vaccines – Inherited immunity • Developed before birth • Genetic trait Assessment • Hemoglobin (Hgb) test measures the amount of oxygen-carrying ability of the blood • Hematocrit (Hct) measures the volume of erythrocytes in the blood Assessment continued • Red blood cell (RBC) counts determine the number of circulating red blood cells in 1 mm3 of blood • Platelet count measure the number of platelets in 1 mm3 of blood to determine clotting ability Disorders • Acquired immunodeficiency syndrome – Dysfunction of the immune system caused by a virus • Allergy – Hypersensitive response by the immune system to an outside substance • Anemia – The blood has an inadequate amount of hemoglobin, red blood cells, or both • • • • Iron deficiency Pernicious Aplastic anemia Sickle cell anemia Disorders • Aneurysm – Weakening of vessel wall • Autoimmune – Conditions in which the immune system of the body turns against itself • Erythroblastosis fetalis – A condition in an unborn baby in which the mother forms antibodies against the antigens in the baby’s blood • Hemophilia – A rare sex-linked genetic blood disease in which the blood is missing a clotting factor • Hepatitis – A viral infection of the blood • Hodgkin’s disease – A malignant cancer of the lymph system • Leukemia – Also called blood cancer, is an abnormal malignant increase in the number and longevity of white blood cells • Phlebitis – Inflammation of the vein • Most often caused by a formation of a clot • Polycythemia – An abnormal increase in the number of blood cells, making the blood thicker and slower flowing • Septicemia – Called blood poisoning, is an infection that occurs when pathogens enter the blood • Sickle cell anemia – A genetic condition that results in malformed red blood cells • Splenomegaly – An enlargement of the spleen caused by an acute infection such as mononucleosis or anemia • Thrombocytopenia – A decrease in the number of platelets in the blood • Thrombosis – A condition in which a blood clot, called a thrombus, forms in the blood vessels