2. Cardiovascular System  Components- blood, heart, blood vessels  1st system to become fully operational (heart beats at the end of the 3rd week of development)

3. Functions of Blood  Transportation of dissolved gases, nutrients, and hormones  Regulation of pH and ion composition of interstitial fluids  Restriction of fluid losses at injury sites (blood clots)  Defense against toxins and pathogens  Stabilization of body temperature

4. Composition of Blood  Fluid connective tissue with a matrix called plasma  Formed elements- RBC transport oxygen, WBC defend body, platelets help clot the blood

5. Blood Facts  Blood Temperature is 38 C  Blood is 5 times as viscous as water  pH is slightly alkaline averaging 7.4  Body contains between 4-6 liters of blood

6. Plasma  Composed of 92% water  7% plasma proteins  1% other solutes

7. Plasma Proteins  Albumins- most common, maintain osmotic pressure, transport fatty acids, steroid hormones, and cholesterol  Globulins- antibodies  Fibrinogens- blood clotting  Peptide hormones- insulin, thyroid stimulating hormones, etc.

9. Formed Elements  Red Blood Cells (RBC)- make-up 99% of formed elements l Hemoglobin- red pigment that binds to oxygen l One drop contains 260 million RBCs, account for 1/3 of all cells of the body l Each RBC can carry more than a billion molecules of oxygen l No nuclei, mitochondria, or ribosomes l Don’t divide or make proteins, life span about 120 days

11. RBC continued  Cells of the liver, spleen, and bone marrow monitor blood for damaged cells  RBC’s are formed in the red bone marrow  Biconcave shape l Provides larger SA to volume ratio, allows oxygen to be absorbed and released quicker l Allow RBC to stack on top of each other, this makes it easier to flow through narrow areas l Allows bending and flexing through very small capillaries

13. Blood Types  Blood types are determined by the type of antigen present on RBCs  Antigens are proteins on the surface of the cell that mark the cell as being “self”  The main surface antigens of RBCs are A, B, and Rh l A person can have A, B, AB, or neither A or B and be type O. In addition you either have a Rh (+), or not (-)

14. Blood type cont.  Your body will produce antibodies (called agglutinins) to combat antigens not found on your own cells. When these agglutinins attack foreign RBC they bind to them and clump in a process called agglutination  People w/out the Rh antigen (Rh-) don’t necessarily carry an antibody against Rh. This antibody is produced when a person is exposed to Rh.

18. White Blood Cells “leukocytes”  Have nuclei and other organelles, but lack hemoglobin  Defend body against invasion by pathogens  Circulate for only a short portion of their lifespan

19. Function of WBC  Neutrophils- difficult to stain, digest bacteria that have been marked by antibodies and then join w/ lysosomes that break down pathogens  Short life span- 10 hours in blood, or only 30 minutes when attacking bacteria

20. Eosinophils and Basophils  Stain darkly, attach object with antibodies, use endocytosis, defend against large multicellular parasites  Basophils- Stain darkly, rare 1%, release histamine, which dilates blood vessels and heparin, which prevents blood clotting

22. Monocytes  Circulate in the blood for only 24 hours, then enter tissues and become macrophages, which engulf debris, and microorganisms in cells

23. Lymphocytes  20-30% of WBCs,  T cells- cell mediated immunity  B cells- make antibodies to attack foreign material in the blood  NK cells- natural killer cells, immune surveillance, important in preventing cancer

24. Hemostasis- cessation of bleeding  Prevents loss of blood when there is damage to vessel walls at the same time providing a framework for tissue repair  3 Phases l Vascular l Platelet l Coagulation

25. Vascular Phase  As soon as there is a cut in the wall of a blood vessel, smooth muscle fibers in the wall contract, lasts for 30 minutes l Decreases diameter of blood vessel, restricting blood flow l Stimulates release of chemical factors that accelerate division of new cells to help in repair

27. Platelet Phase  Platelets in the blood stick to the walls of the vessel surrounding cut as well as collagen fibers exposed to the cut, 15 seconds after injury  Platelet plug  Platelets release compounds that stimulate contraction of smooth muscle and more platelets to stick to plug, positive feedback

28. Coagulation Phase  30 seconds after injury  Complex sequence of steps, fibinogens that circulate in blood are changed into fibrin which is an insoluble fiber  Fibrin forms over platelet plug  Clotting requires Ca 2+ and 11 different proteins (clotting factors)  Some of these clotting factors create a positive feedback loop to increase rate of coagulation