Blood has several functions including transport, defense, and regulation. It is composed of plasma and formed elements such as red blood cells, white blood cells, and platelets. Red blood cells contain hemoglobin and carry oxygen, while white blood cells help fight infection. Platelets help form blood clots to prevent blood loss. Different blood types are determined by the presence or absence of antigens on red blood cells. Compatible blood types are required for safe blood transfusions. Some diseases of the blood include anemia, sickle cell disease, and leukemia.

1. Chapter 11 Blood

2. Composition Plasma: Yellowish liquid that contains various organic and inorganic molecules dissolved in water. Formed elements: Cells including white and red blood cells as well as platelets.

3. Functions of Blood Transport: To move materials like oxygen, carbon dioxide, and hormones to the organs. Defense: Protects the body from pathogens (infectious agents) and forms clots to prevent blood loss. Regulation: Helps regulate body heat, pH, and water levels.

4. Plasma Contains many proteins that help maintain homeostasis. Two important plasma proteins are antibodies (help fight infections) and fibrinogen (required for blood clotting).

5. Blood Cell Formation Process is called hematopoiesis. Stem cells have the ability to differentiate into different types of cells. This is a hot topic in politics and research because it holds the potential of being able to regenerate body tissue in the lab. For more information on stem cells visit: http://stemcells.nih.gov/info/basics/

6. Red Blood Cells (RBCs or (Erythrocytes) No nucleus when mature. Contain hemoglobin, the molecule which carries oxygen. Formed by the red bone marrow stem cells. Live only about 120 days and are then destroyed by the liver and spleen.

7. White Blood Cells (WBCs or Leukocytes) Less numerous than RBCs. Derived from stem cells in the red bone marrow. Fight infections. Able to squeeze through capillary walls and enter the lymph where they continue to fight infection.

8. Platelets Formed elements responsible for hemostasis (the cessation of bleeding). Live only about 10 days.

9. Hemostasis Vascular spasm: 1 st response to bleeding. Constriction of a broken blood vessel. Platelet plug formation: Platelets adhere to exposed collagen fibers. Coagulation: Many reactions occur during this process. The result is that firbrin threads wrap around the platelet plug and RBCs are trapped within the threads.

10. Gas Exchange within Capillaries Influenced by: Blood pressure: the pressure against blood vessels caused by the pumping of the heart. Diffusion: movement of substances from an area of higher concentration to an area of lower concentration. Osmotic pressure: the force caused by a difference in solute concentration on either side of a membrane.

11. Arterial End of Capillary Water and other small molecules leak out of capillaries creating tissue fluid. Molecules leaving include water, oxygen, amino acids, & glucose .

12. Midsection of Capillary Carbon dioxide and other waste products diffuse into the capillaries.

13. Venous End of Capillary Blood is a dark maroon color because it lacks oxygen. Water that previously left the capillary reenters it.

14. Blood Typing Based on the presence or absence of two possible antigens on the surface of blood cells: A type and B type antigen. Having A type antigen results in type A blood. Having B type antigen results in type B blood. Having both A & B type antigens results type AB blood. Having neither A type nor B type antigen results in type O blood.

15. Blood Transfusions It is very important that bloods involved in transfusions are compatible. Blood types that are incompatible will result in clumping of the blood. Anyone can receive type O blood because it does not contain any antigens. Called a universal donor. People with type AB blood can receive any type blood because their blood contains both antigens. Called the universal recipient.

16. Rh Blood Groups Rh is another factor present in red blood cells. People without the RH factor do not have antibodies to the factor but make them when exposed to the Rh factor.

17. Diseases of the Blood Anemia is a condition that results from a reduction in the amount of hemoglobin or RBCs or the bursting of RBCs. Sickle-cell disease is inherited. Cells tend to wear out or rupture easily as they pass through the capillaries. Leukemia is a cancer of the blood characterized by abnormally high numbers of white blood cells. Sickle cell shaped red blood cells

18. Diseases of the Blood Continued Hemophilia: An inherited clotting disorder caused by a deficiency in a clotting factor. Hemolytic disease of the newborn. A disease where a Rh+ child is born to a Rh- mother. Excessive RBC destruction can lead to brain damage, mental retardation, or death of the child.