Blood anatomy Components • Formed elements: living blood cells are suspended in the plasma (nonliving). • Blood is connective tissue • Buffy coat: the thin whitish layer between the RBCs and the plasma. – Leukocytes: white blood cells – Platelets: cell fragments that function in the blood-clotting process. – Both of these are less than 1% of blood • Hematocrit: erythrocytes that account for 45% of the total volume of blood • Plasma: makes up 55% of blood. Physical characteristics and volume • • • • • • • • • • • Sticky Opaque Metallic taste Salty Red Heavier than water and 5 times thicker Alkaline pH 7.35-7.45 Temperature: 100.4 degrees F 8% of body weight Healthy males have 5-6 quarts. Plasma • • • • 90% water Most plasma proteins are made by the liver Albumin: osmotic pressure of blood Clotting proteins: help stem blood loss when a vessel is injured. • Antibodies: help protect the body from pathogens • Acidosis: too acidic • Alkalosis: too basic Formed elements • Erythrocytes: Red blood cells, they ferry oxygen in blood to all cells of the body. • RBCs lack a nucleus. • Hemoglobin: iron containing protein that transports most of oxygen – Lack of mitochondria and make ATP by anaerobic mechanisms • RBCs are normally 5 million cells per cubic millimeter of blood. • Blood contains 12-18 g hemoglobin per 100 mL blood. – Higher in men than in women. Formed elements cont. • Leukocytes: white blood cells. – Protects against diseases – 4000-11,000 WBCs per cubic millimeter – Can slip in and out of vessels. (diapedesis) – Leukocytosis: a WBC count above 11,000 cells/mm3 – Leukopenia: abnormally low WBC Other leukocytes • Granulocytes: lobed nuclei, include neutrophils and basophils – Neutrophils: multiplied nucleus, avid phagocytes at sites of acute infections – Eosinophils: blue-red nucleus, increases rapidly during allergies and infections by parasitic worms. – Basophils: rarest of the WBCs, large histamine-containing granules • Agranulocytes: spherical nuclei, include lymphocytes, and monocytes. – Lymphocytes: large dark purple nucleus, in lymphatic tissue – Monocytes: largest WBCs , change to macrophages with huge appetites Platelets • Fragments of bizarre multinucleate cells called megakaryocytes. • Hemostasis: stoppage of blood flow – Thrombus: a clot that develops and persists in an unbroken blood vessel – Embolus: if a thrombus breaks away from the vessel wall and floats freely in the bloodstream – Blood clots in 3-6 minutes – Fibrin is a clot formed during hemostasis. – Lack of Vitamin K in body causes undesirable clotting. – Calcium is needed for clotting properly Blood groups and transfusions Losses of 15-30% lead to pallor and weakness Losses of over 30% cause severe shock which can be fatal Blood can be stored for up to 35 days in a refrigerator. Human blood groups • Antigens: body recognizes as foreign • ABO blood groups: are based on the A or B a person inherits. • Absence of both is O blood group • Rh blood groups: positive or negative – Pregnant women who carry a positive baby in a negative mother will have to have RhoGAM shots to allow the baby to live. Homeostatic Imbalances • Anemia: a decrease in the oxygen carrying ability of the blood – 1. lower than normal number of RBCs – 2. abnormal or deficient hemoglobin content in the RBCs – Lack of vitamin B12 – Lack of iron – Genetic defect – Hemorrhage • Jaundice: yellowed tissue due to rapid break down of hemoglobin.