Anatomy Exam III 1 Whole blood has two components 1 Blood plasma 55 2 Formed elements 45 99 RBC 1 WBC saturated with oxygen bright red unsaturated dark red slightly alkaline 38 degrees Celsius Blood is considered a connective tissue for two basic reasons 1 embryologically it has the same origin mesodermal as do the other connective tissue types 2 blood connects the body systems together bringing the needed oxygen nutrients hormones and other signaling molecules and removing the wastes hemopoiesis makes white blood cells varies in response to presence of pathogens before birth occurs in embryo sac last 3 months before birth in red bone marrow 2 Functions of Blood 1 Transports oxygen 2 Carries nutrients 3 Transports heat and waste products for elimination 4 Carries hormones 5 Regulates pH 6 Adjusts body temperature 7 8 Clots 9 Fight disease Influences water content of cells 3 Blood Plasma 91 5 water 8 5 solutes mostly proteins Plasma Proteins albumins globulins fibrinogen immunoglobulin antibodies electrolytes nutrients enzymes hormones gases waste products Functions Disables invading antigens clot regulate nutrients in the blood homeostasis 4 Erythrocytes have no nuclei or organelles whole cells contain hemoglobin males 5 4 million RBCs per microliter of blood females 4 8 million biconcave discs 7 8 micrometer shape allows for maximum diffusion of gas molecules strong and flexible plasma membrane allows them to squeeze through narrow capillaries do not use any of the oxygen they transport contains hemoglobin live only about 120 days cells burst and are removed and destroyed by macrophages in th spleen and liver products are recycled Erythropoiesis starts in red bone marrow with a proerythroblast proerythroblast divides several times producing cells that synthesize hemoglobin a reticulocyte forms by ejecting its nucleus and moving out of red bone marrow reticulocytes mature into erythrocytes 1 2 days after moving out of marrow 5 Hemoglobin consists of globin and heme each heme ring contains one iron molecule can combine reversibly with one oxygen molecule allowing each hemoglobin to bind to 4 oxygen molecules oxygen is picked up from the lungs and brought to interstitial fluids and cells transports about 23 of the total carbon dioxide as blood flows through the lungs the carbon dioxide is released from hemoglobin and then exhaled hemoglobin can also release NO which causes vasodilation 6 Erythrocyte disorders Anemia characterized by reduced numbers of RBCs or a decreased amount of hemoglobin in the blood fatigue intolerant to cold pale skin lack of oxygen needed for ATP and heat production low hemoglobin circulation Iron deficiency anemia most common type of anemia cause by inadequate absorption of iron excessive loss ofiron increased iron requirement or insufficient intake of iron mostly affects women due to menstral blood losses gastrointestinal losses ulcers also lead to it megaloblastic anemia Pernicious anemia inadequate intake of folic acid B12 red bone marrow produces large abnormal red blood cells may be caused by drugs that alter gastric secretion or treat cancer Insufficient hemopoiesis inability of the stomach to produce intrinsic factor which is needed for absorption of vitamin B12 in the small intestine Hemorrhagic anemia Hemolytic anemia excessive loss of RBCs through bleeding RBC plasma membranes rupture prematurely released hemoglobin pours into the plasma and damage the filtering units in the kidneys results from inherited defects such as abnormal red blood cell enzymes or from parasites toxins or antibodies Thalassemia deficient synthesis of hemoglobin a group of hereditary hemolytic anemias small pale and short lived primarily occurs in populations from countries bordering the Mediterranean Sea destructions of red bone marrow caused by toxins gamma radiation and certain medications that inhibit enzymes Aplastic anemia Sickle cell Disease the RBCs contain Hb S Hb S gives up oxygen in the interstitial fluid which forms long stiff rodlike structures that bend into a sickle shape sickle cells rupture easily erythropoiesis cannot keep pace with hemolysis sickle cells breakdown prematurely which leads to anemia fatigue paleness delayed development jaundice blocked blood vessels infection fever inflammation excessive thirst painful episodes inherited disease must have 2 sickle cell genes to have severe anemia primarily found in Mediterranean Europe sub Saharan Africa and tropical Asia some patients benefit from taking hydroxyurea Not always for long term use Polycythemia artificial blood doping athletes inject Procrit or Epogen to increase volume of RBC dangerous because this increases the resistance to blood flow and makes the blood more difficult to pump Can lead to stroke or heart attacks banned by Olympics natural blood doping train at higher altitudes so the body increases the production of RBC common in Kenyan runners 7 Leukocytes have nuclei and a full complement of other organelles do not contain hemoglobin classifies as granular or agranular combat invaders by phagocytosis or immune responses inflammation form selectins and integrins and defensins Granular Leukocytes can be distinguished under a light microscope Neutrophil granules of a neutrophil are smaller than those of other leukocytes pale lilac evenly distributed neutrophilic has 2 5 nuclear lobes which increases with age unleash chemicals that destroy the pathogen Eosinophil large uniform sized granules within an eosinophil eosinophilic red orange with acidic dyes do not cover or obscure the nucleus usually has 2 lobes release enzymes that combat allergic reactions phagocytize antigen antibody complexes Basophil round variable sized granules of a basophil blue purple with basic dyes granules commonly obscure the nucleus which has 2 lobes release granules that intensify the inflammatory reaction Agranular Leukocytes not visible under a light microscope because of their small size and poor staining qualities Lymphocyte nucleus stains dark and is round or slightly indented cytoplasm stains sky blue and forms a run around the nucleus small 6 9 micrometers in diameter Large 10 14 micrometers destroy bacteria attack viruses attack infectious microbes Monocyte kidney shaped nucleus blue gray foamy cytoplasm due to azurophilic granules arrive at infections last but have the most numbers and destroy the most clean up cellular debris Hemopoietic Growth Factors used when a person s natural ability to form new
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