Anatomy and Physiology of Circulatory System

Anatomy and Physiology of Blood

1. BLOOD

2. CENTRIFUGE

3. VISCOSITY Refers to how thick or sticky a fluid is  The more viscous the fluid, the thicker it is

4. BLOOD CELL FORMATION HOMOPOIESIS – production of blood 2 TYPES OF HOMOPOIESIS:  RED BONE MARROW -  found in the ends of long bones and in flat irregular bones such as the sternum, cranial bones, vertebrae, and pelvis—produces all types of blood cells. LYMPHATIC TISSUE -  found in the spleen, lymph nodes, and thymus gland—supplement blood cell production by producing lymphocytes, a specific type of WBC.

5. RED BLOOD CELLS (RBC)  Charged with delivering oxygen to cells and removing carbon dioxide, red blood cells, or erythrocytes , are critical to survival.  Blood contains more RBCs than any other formed element.

6. A normal RBC is shaped like a disc with a sunken center. This shape gives the cell a large surface area through which oxygen and carbon dioxide can readily diffuse. RBCs lose almost all of their organelles during development. Because they lack a nucleus and DNA, they cannot replicate themselves. contains stretchable fibers that make it flexible, allowing it to fold and stretch as it squeezes through tiny capillaries. When the cell emerges from the tight confines of a narrow vessel, it springs back to its original shape.

7. HEMOGLOBIN Over a third of the interior of a RBC A red pigment that gives blood its color

8. NORMAL VALUES • Hematocrit: Female: 37%–48%; Male: 45%–52% • Hemoglobin: Female: 12–16 g/dl; Male: 13–18 g/dl • RBC count: Female: 4.2–5.4 million/ mcL ; Male: 4.6–6.2 Million/ mcL Bright red when oxygenated and a deep maroon when deoxygenated. Blood is never blue. Because of the loss of blood through menstruation, women of reproductive age have the highest nutritional requirement for iron. Other nutritional requirements for red blood cell formation include vitamin B12, folic acid, and vitamin C.

9. Sickle Cell Disease

10. Life Cycle of RBCs Cells circulate for about 120 days before they die, break up, and are consumed by phagocytic cells in the spleen and the liver. Erythropoiesis :  the process of producing new erythrocytes is maintained through a negative feedback loop. Takes 3-5 days

11. Breakdown of RBCs

12. Bile in the intestines give feces its color Urochrome – breakdown of hemoglobin gives urine it yellow color Jaundice -  When the destruction of RBCs becomes excessive (hemolysis), instead of being excreted into the intestines, the excess bilirubin enters the tissues, causing the skin and sclera to take on a yellowish hue.  Physiological jaundice - newborns often develop jaundice shortly after birth (immature livers begin the task of clearing bilirubin from the blood) Polycythemia – state in which the body has excess RBCs

13. WHITE BLOOD CELLS Also called leukocytes The body’s line of defense against invasion by infectious pathogens. Contains nucleus Contain a number of other internal structures, some of which look like  granules  when stained and examined under a microscope.

14. Granulocytes Besides containing  granules  in the cytoplasm, granulocytes also contain a single multilobular nucleus.  Three types: neutrophils, eosinophils, and basophils.

15. Neutrophils Most abundant in WBCs Function: highly mobile, quickly migrates out of blood vessels and into tissue spaces, where they engulf and digest foreign materials Worn-out neutrophils – form the main component of pus

16. B. Eosinophils 2%-5% of the circulating WBCs Few exist in bloodstream but numerous in the lining of respiratory and digestive Function: involved in allergic reaction, also kills parasites

17. C. Basophils Fewest of the WBCs; 0%-1% Function: secretes heparin (anticoagulant) which prevents clotting in the affected area so WBC can enter. Also secretes histamine – causes blood vessels to leak = attracts WBCs

18. Agranulocyte Unlike granulocytes, agranulocytes lack cytoplasmic granules; the nuclei of these WBCs also lack lobes.  Two types: lymphocytes and monocytes When cells become inflamed from a bacterial infection, they release  chemicals that attract neutrophils and other phagocytic WBCs to the infection site.

19. Lymphocytes Second most numerous in the WBCs: 25% - 33%  Smallest of WBCs Function: responsible for long-term immunity T-lymphocytes – directly attack an infected or cancerous cells B- lympocytes  - produce antibodies against specific antigens 

20. B. Monocytes 3% - 8% of WBCs Largest and highly phagocytic that can engulf large bacteria and viral-infected cells When cells become inflamed from a bacterial infection, they release chemicals that attracts neutrophils and other phagocytic WBCs to the infection site. 

21. Leukopenia – abnormally low WBC count (d/t viral illnesses, AIDS, lead poisoning)  Leukocytosis – elevated WBC count = indicates infection/allergy  Differential count (diff count) - count of each WBCs Elevated neutrophils = bacterial infection  Elevated eosinophil = allergic reaction/parasitic infection 

22. PLATELETS AKA thrombocytes Second most abundant formed element (each microliter of blood = 140,000 to 400,000 platelets  Plays key role in stopping bleeding (HEMOSTASIS)

23. HEMOSTASIS  VASCULAR SPASM Blood vessel injured --> spasm of smooth muscle fibers --> constricts BV --> slows the flow of the blood (This response is only temporary but gives the other hemostatic mechanisms time to activate)

24. 2. FORMATION OF A PLATELET PLUG Exposed collagen fibers --> rough spot in normally slick interior of BV --> changes in passing platelets --> sticky platelets

25. 3. FORMATION OF A BLOOD CLOT  Blood clotting or coagulation , involves a complex series of chemical reactions using proteins called clotting factors . Specifically, when the damaged blood vessel and surrounding tissues—areas outside or extrinsic to the blood—release clotting factors, this kicks off a cascade of events called the extrinsic pathway .  When the clotting factors are activated within the blood—such as by the platelets as they adhere to the collagen in the damaged vessel wall—this sets off a different cascade of events called the intrinsic pathway .

26. BLOOD CLOTTING DISORDERS Thrombus – an unwanted blood clot inside of a vessel .  Embolus – blood clot circulates through the bloodstream.  TX: heparin or the oral anticoagulant warfarin (Coumadin) Heparin blocks the action of thrombin Warfarin (Coumadin) blocks the effects of vitamin K on the liver --> liver produces less prothrombin = less thrombin.  Hemophilia—rare disorder results from a deficiency of one of the clotting factors. People with hemophilia lack the ability to form blood clots, even minor injuries can become life threatening. 

27. Tissue plasminogen activator (t-PA) —one of the substances that stimulates the conversion of plasminogen into plasmin—can be administered as a drug.  early treatment to dissolve clots causing strokes and heart attacks

28. BLOOD TYPES This scientist discovered that the surface of each red blood cell carries a protein called an antigen (aka agglutinogen ).  There are two antigens: A and B.

29. While the blood cell carries antigens, the blood plasma carries antibodies (called agglutinins ) against the antigens of the other blood types.

30. Transfusions are successful as long as the recipient’s plasma doesn’t contain antibodies against the ABO type being transfused. If such antibodies are present, they will attack the donor’s RBCs, causing a transfusion reaction .

31. clumping of RBCs ---> blocks blood vessels --> cutting off the flow of O2 --> RBCs burst ( hemolysis ) --> release their hemoglobin into the bloodstream --> block tubules in kidneys --> renal failure --> DEATH 

32. THE Rh GROUP