Chapter 14 Blood

Functions Transportation –Food and oxygen to cells –Waste from cells –Hormones –Heat from the core to the surface

Blood Characteristics Plasma = fluid portion of blood. –55% of the blood’s volume –90% water, 8% proteins, and 2% acids and salts. Blood Cells: –Erythrocytes – red blood cells (rbc) (99%) –Leukocytes – white blood cells (.2%) –Thrombocytes – platelets (.6 – 1%)

Blood Characteristics Continued Blood volume –Varies with age, body type, and sex –Body Fat decrease in body fat = increase blood volume. More oxygen to cells = increase energy –About pints of blood

Blood Cells Erythrocytes (Red blood cells) –Appearance No nucleus or organelles Concave shape (donut) Large surface area to carry oxygen Great elasticity –Abnormalities Sickle cells – crescent shaped RBC’s –Hemoglobin – molecule in RBC Contains 4 iron atoms – which allows oxygen to bind Men carry more than women Color of blood depends on hemoglobin content

Blood Cells Continued Erythrocytes –Anemia – the state of having a deficiency of hemoglobin content in RBC’s –Blood doping – increases RBC’s = increase in hemoglobin = more oxygen to cells –Formation of RBC’s – Erythoropoiesis Mature in red bone marrow Contain reticulocytes – help doctors diagnose how much blood is being made –Destruction of RBC’s Live 3-4 months Cells lining blood vessels phagocytose RBC’s Iron is recycled in the liver Bilirubin is formed = yellow pigment When bilirubin accumulates in liver - jaundice

Homeostatic Mechanism – Keeps RBC’s Constant Normal Red Blood Count Some Factor (Car Wreck) Tissue Hypoxia Increased secretion of erythroprotein by kidney and liver Decreased # of RBC’s Hormone Increased erythropoiesis (rbc production) by red bone marrow Increased # of RBC’s Tends to restore

Blood Cells Continued Leukocytes (White blood cells) –Appearance Five types in body – lymphocytes, neutrophils, eosinophils, monocytes, and basophils –Function Fight infection Phagocytosis – ingest and digest microbes –Formation In red bone marrow or lymphatic tissue Life span not known (3-12 days or 3-6 months)

Blood Cells Continued Platelets –Appearance Colorless, irregular spindles or oval disks –Function Hemostasis – stopping of blood flow to area Clotting – plugging up ruptured vessels –Formation In red bone marrow, lungs, and spleen About a 10 day life span

Blood Types A person’s blood type depends on the type of antigen on the RBC membrane –Type A – antigen A on RBC –Type B – antigen B on RBC –Type AB – antigen A and B on RBC (universal recipient) –Type O – no antigen A or B on RBC (universal donor) –Rh-factor = Rh antigen on RBC Rh-positive = Rh antigen present Rh-negative = Rh antigen not present

A type of protein

Blood Types Continued Antigen – stimulates the formation of antibodies (identify and neutralize foreign objects) that combine with antigen to clump cells. It is a type of protein found on the membranes of red blood cells. –Danger in blood transfusions –Plasma never contains antibodies against the antigen present on RBC’s

Blood Types Continued Anti-Rh antibodies –No blood usually contains this antibody –Can show up in blood of an Rh-negative type comes into contact with an Rh-positive type Transfusions Pregnant women with Rh-negative blood –Fetus is Rh-positive (gene from dad) –Blood mixes at birth – mother’s body makes anti-Rh antibodies (no harm to mother) –During the 2 nd pregnancy the antibodies could attack the fetus and destroy = erythroblastosis fetalis

Blood Types Continued

Anti-Rh antibodies –No blood usually contains this antibody –Can show up in blood of an Rh-negative type comes into contact with an Rh-positive type Transfusions Pregnant women with Rh-negative blood –Fetus is Rh-positive (gene from dad) –Blood mixes at birth – mother ’ s body makes anti-Rh antibodies (no harm to mother) –During the 2 nd pregnancy the antibodies could attack the fetus and destroy = erythroblastosis fetalis

Blood Coagulation Mechanism –Vessel is cut –Bleeding occurs –Platelets aggregate at the site of injury –Formation of a chemical with chemical fibrinogen –Insoluble fibrin is made and tangles with RBC which forms the clot –RBC’s give scab a red/brown color

Blood Coagulation Continued Opposition of Clotting Mechanism –Smooth surface of blood vessel –Antithrombins – heparin No thrombin made – no clot

Blood Coagulation Continued Factors that Hasten Clotting –Rough spot on blood vessel lining –Slow blood flow to area – atherosclerosis Bed patients must be moved frequently –Clots seem to grow once started –Clinical method Apply gauze – rough surface Heat massage

Blood Typing

Blood Transfusion Game