Physiology of Blood

amazing facts about blood The human body manufactures 17 million red blood cells per second. If stress precipitates a need the body can produce up to 7 times that amount. (That’s up to 119 million red blood cells per second). It only takes 20 to 60 seconds for a drop of blood to travel from the heart, through your body, and back to the heart again. Cows have 800 (and possibly more) blood types. George Washington was bled to death by doctors, who were treating him for a cold. Bloodletting was a common medical practice in those times in order to remove “dirty blood,” when in reality it only weakens the patient. Half or more of his blood was removed within a few hours. The human cornea extracts oxygen directly from the air. It has no blood supply. There is about 0.2 milligrams of gold in our bodies, most of which is in our blood. However, you would need to bleed 40,000 people dry just to collect enough blood to make an 8-gram souvenir. Mosquitoes prefer blood type O to any other. Pregnant women have about 50% more blood by week 20 of pregnancy than they did before they conceived. A 2014 study published in the journal Neurology found those with blood type AB were twice as likely to experience memory problems as those with type O blood. All blood isn’t red. Crabs have blue blood. Earthworms and leeches have green blood. Many invertebrates, such as starfish, have clear or yellowish blood.

Outline 1.describe the blood components and hemopoiesis. 1.describe the blood components and hemopoiesis. 2.describe red blood cell, its function, and explain the mechanism for regulation of its production. 2.describe red blood cell, its function, and explain the mechanism for regulation of its production. 3.expound the plasma proteins and their functions. 3.expound the plasma proteins and their functions. 4.understand the composition, types, forms, synthesis, destruction and abnormalities of Hb. 4.understand the composition, types, forms, synthesis, destruction and abnormalities of Hb. 5.characterize the types of anemia. 5.characterize the types of anemia. 6.explain the types, functions, and the formation of white blood cells. 6.explain the types, functions, and the formation of white blood cells. 7.describe the types of immunity and the development of the immune system. 7.describe the types of immunity and the development of the immune system. 8.understand the inflammatory process. 8.understand the inflammatory process. 9.expound blood types, blood incompatibility, and transfusion reaction. 9.expound blood types, blood incompatibility, and transfusion reaction. 10.understand platelets and their functions. 10.understand platelets and their functions. 11.describe hemostasis and blood coagulation. 11.describe hemostasis and blood coagulation. 12.explain fibrinolysis and the anticlotting mechanisms. 12.explain fibrinolysis and the anticlotting mechanisms. Objectives after studying this chapter, you should be able to..

FUNCTIONS OF THE BLOOD 1. Transport of O 2, nutrients and hormones to the tissues and carries CO 2 to the lungs and other products of metabolism to the kidneys to be excreted. 2. Participates in the regulation of body temperature, pH and electrolyte concentrations of interstitial fluid within the normal ranges through a constant exchange of molecules with the interstitial fluid. 3. Blood also serves essential body protective functions, such as combating invading microorganisms, mediating inflammation, initiating immune responses to foreign materials, and maintaining hemostasis.

electrolytes glucose urea lipids albumin globulins fibrinogen RBCs WBCs platelets such as

PLASMA PROTEINS TYPES ALBUMIN (4.5 g/dl)  (58%) GLOBULINS (2.5 g/dl)  (38%) ( , ,  ) FIBRINOGEN (0.3 g/dl)  (4%) FUNCTIONS 1- Exert colloid osmotic pressure. 2- Act as buffers. 3- Transport hormones and other substances in blood. 4- Provide the body with immunity. 5- Involved in blood clotting. 6- Act as a source for rapid replacement of tissue proteins.

HEMOPOIESIS SITES In the early weeks of embryonic life In the Yolk sac After 12 weeks gestation In the liver, spleen, lymph nodes Later on and after birth In the bone marrow of all bones After 20 years of age In the bone marrow of only flat bones and upper femur and humerus

HEMOPOIESIS Reticulocyte count is used as a clinical measurement of erythropoietic activity 0.5%-1.5% are Reticulocytes

 Non nucleated discs.  Biconcave in shape ;  lack mitochondria,  Incapable of aerobic respiration (use anaerobic glycolysis)  High surface area /volume ratio - maximum surface area - greatest deformability  After 120 days, they die in the spleen  Normal RBC count: male 5,200,000±300,000/µL female 4,700,000±300,000/µL  RBC count varies with age, sex, altitude.

ERYTHROPOIESIS Basic substances required: Proteins, Iron, Vit.B 12, Folic acid, Vit.B 6. ERYTHROPOIESIS

Hemoglobin molecule

Forms of normal Hb OxyHb Hb + O2 CarbaminoHb Hb + CO2 CarboxyHb Hb + CO SulfHb Hb + Sulfur MetHb Fe +2 Fe +3 (oxidation)