The Blood “Transport System”

FUNCTIONS Transports nutrients and wastes Distributes body heat Delivers hormones Helps fight disease

Composition of the Blood Blood is a connective tissue! Blood makes up ~8% of total body weight ~55% plasma ~45% formed elements 4 to 5 liters for average females 5 to 6 liters for average male *the higher percent body fat the less blood you have per kilogram of weight

Plasma 90% water 10% solutes (salts and minerals)

Formed Elements Red Blood Cells (RBCs) (erythrocytes) White Blood cells (WBCs) (leukocytes) Platelets (thrombocytes) RBCs make up about 45% of blood volume WBCs and platelets make up about 1%

Blood Composition

Red Blood Cells(erythrocytes) Mature cells loose/lack a nucleus and most organelles Hemoglobin, red pigment, makes up 1/3 of cell volume RBCs are highly flexible because of spectrin protein Flexibility can determine the speed of blood flow Men have more RBCs because of the influence of testosterone

Hematocrit tubes Hematocrit tubes show normal, anemic and polycythemia

Function of RBCs structure = function slight dimple in Hemoglobin and carbonic anhydrase both work to transport O2 and CO2 structure = function slight dimple in center surface area

Hemoglobin Made up of 4 protein chains called globins Each chain is bound to a heme group which contains one Fe The iron can bind to one O2 Each globin can bind to one CO2

Formation of RBCs Erythropoiesis begins with hematopoietic stem cells in red bone marrow New red blood cells take 4 days to mature Sickle cell anemia- inherited defect, causes a defective hemaglobin. Cells become sickle shaped and can clog blood vessels. (coevolution at work!)

Formation of RBCs Decreased levels of oxygen stimulate the production of RBCs by secreting erythropoietin (EPO) from the kidneys

Destruction of RBCs ~200 million RBCs are formed each day to replace the equal amount destroyed Lifespan of RBCs is 105-120 days Lining of blood vessels in liver and spleen destroy damaged or fragmented RBCs Components of the cells are broken and reused to make more RBCs Bone marrow must have a constant supply of iron, B12, and amino acids to make new RBCs B12 is called the antianemic principle

White Blood Cells Special cells that help fight infection Many different types Phagocytize foreign matter Produce antibodies HIV attacks these cells

White Blood Cells(leukocytes) Granulocytes Neutrophils – multi-lobed make up about 65% of WBC count Move from blood vessels into tissues through diapedesis Eosinophils – orange-ish Fight infection caused by parasitic worms and allergic reactions Basophils – dark purple Granules contain histamine and heparin (anticoagulant) neutrophils eosinophils basophils

Who has pimples? BEN does. Basophils, eosinophils, neutrophils

White Blood Cells(leukocytes) Agranulocytes Lymphocytes – “eyes” Ingest infected or cancerous cells (phagocytosis) Create antibodies Monocytes – kidney-shaped lobe Largest of the leukocytes Ingest infected cells lymphocytes monocytes

White blood cells numbers Differential white blood cell count can indicate different types of infections. Certain drugs (such as cancer treatments)can cause leukopenia (low WBC count)

Platelets Are small cells with special characterisitcs: agglutination, adhesiveness, and aggregration. Once they leave the blood vessels they become misshapen and clump together

Platelet Action Platelets have two roles, hemostasis (blood flow stoppage) and coagulation (blood clotting). Hemostatic action will occur when a platelet encounters a tear in a capillary. It will form a platelet plug to stop blood from flowing into the tissue. Coagulation occurs when sticky platelets release chemicals to cause the blood to clot. Platelets have a life span of ~7 days resting platelets activated platelets

Blood Clotting Clotting Factors in the blood, in blood cells, and in tissues combine in a metabolic cascade when damage to cells or tissues occurs. Factors in the blood are called intrinsic Factors in tissues are called extrinsic Prothrombin→Thrombin→Fibrinogen→Fibrin→Clot

Blood Clotting As platelets bind to injury site they release chemicals that trigger the clotting process. Fibrin forms at site of injury and entangle RBCs. Calcium in the blood and vitamin K are an important cofactors in coagulation. Arteriosclerosis can increase clotting because platelets stick to rough patches. Applying a rough surface such as gauze, heat or pressure as well as direct application of clotting agents can speed up clotting.

Clot Dissolving After a while, the clot must dissolve. Fibrinolysis Heparin is major anticoagulant produced in by the liver

Blood Disorders Anemia-inability of blood to transport O2 Aplastic anemia-caused by destruction of bone marrow, drugs, radiation or idiopathic. Pernicious anemia- results from lack of vitamin B12 Folate-deficiency anemia- results from lack of folic acid, common in alcoholics Acute blood loss anemia- occurs after serious injury.

Blood Disorders Clotting disorders Thrombus- is a localized blood clot, thrombosis. Embolus- when a clot circulates in blood stream, embolism. Hemophilia is an inherited (sex linked) disorder where the blood has difficulty clotting. No Factor VIII (8)

Blood Types Blood type is determined by the type of antigens found on the outside of RBC’s. Blood plasma will then contain antigens only for the type not found on the person’s RBC’s.

Agglutination Agglutination will only occur when antibodies encounter foreign antigens.

Blood Donations Homologous transfusion- when a persons receives a matching blood type from another person Autologous transfusion- when a person donates blood to themselves.

Rh factor Rh+ positive persons carry the Rh antigen Rh- negative person has no antibodies against the antigen until they are exposed to it through either blood transfusions or pregnancy.

a. Rh+: has antigen b. Rh-: no antigen, recessive