Chapters 10 & 11 Blood and Cardiovascular System

1. Chapters 10 & 11Blood and Cardiovascular System Course of Study: 9.) Identify structures and functions of the cardiovascular system. • Tracing the flow of blood through the body • Identifying components of blood • Describing blood cell formation • Distinguishing among human blood groups • Describing common cardiovascular diseases and disorders Examples: myocardial infarction, mitral valve prolapse, varicose veins, arteriosclerosis

2. Components of Blood

3. Blood • The only fluid tissue in the human body • Classified as a connective tissue • Living cells = formed elements • Non-living matrix = plasma

4. Components of Blood: • Although blood appears to be a thick, homogenous liquid, the microscope reveals it has both solid and liquid components • Blood is a complex connective tissue (it is the only liquid tissue) in which living blood cells, the formed elements, are suspended in a nonliving fluid matrix called plasma.

5. Components of Blood: • Blood in a centrifuge: • The heavier formed elements are packed down • The plasma rises to the top • Most of the reddish mass at the bottom of the tube consists of erythrocytes, the red blood cells that function in oxygen transport • Although, it is barely visible in there is a thin, whitish layer called the “buffy coat” at the junction between the formed elements and the plasma. This layer contains leukocytes (leuko=white), the white blood cells that act in various ways to protect the body, and platelets, cell fragments that function in the blood clotting process. • Erythrocytes normally account for about 45% of the total volume of a blood samples, a percentage known as a “hematocrit”. • White blood cells and platelets contribute less than 1%. • Plasma makes up most of the remaining 55% of whole blood.

6. Figure 10.1 in your book, pg.329

7. Physical Characteristics and Volume • Blood is a sticky opaque fluid with a characteristic metallic taste • Depending on the amount of oxygen it is carrying, the color of blood varies from scarlet (oxygen-rich) to a dull red (oxygen-poor) • Blood is heavier than water and about five times thicker, or more viscous, largely because of its formed elements. • Blood is slightly alkaline (basic) with a pH between 7.35 and 7.45. • Its temperature is always slightly higher than body temperature (38°C or 100.4°F) • Blood accounts for approximately 8% of body weight, and its volume in healthy males is 5-6 liters, or approximately 6 quarts…so what is it in women? (2 point bonus…)

8. Plasma • Is approximately 90% water • Is the liquid part of the blood • Over 100 different substances are dissolved in this straw-colored fluid such as nutrients, salts (electrolytes), respiratory gases, hormones, plasma proteins, and various wastes and products of cell metabolism • The composition of plasma varies as cells remove or add substances to the blood…assuming a healthy diet, however, the composition is kept relatively constant by various homeostatic mechanisms of the body

9. Plasma Proteins • The most abundant solutes in plasma • Except for antibodies and protein-based hormones, most plasma proteins are made by the liver. • Serve a variety of functions • Albumin: contributes to osmotic pressure of blood, which acts to keep water in the bloodstream • Clotting Proteins: Help stem blood loss when a blood vessel is injured • Antibodies: Help protect the body from pathogens (disease causing organisms) • Plasma proteins are NOT taken up by cells to be used as food fuels or metabolic nutrients, as are other solutes such as glucose, fatty acids, and oxygen.

10. Formed Elements • Erythrocytes • Leukocytes • Platelets • If you observe a stained smear of human blood under a microscope, you will see smooth, disc-shaped red blood cells, a variety of gaudily stained white blood cells, and most likely, some scattered platelets that look like debris. • Erythrocytes vastly outnumber the other types of formed elements.

11. Erythrocytes: “red blood cells” (RBCs) • Salmon-colored, biconcave disks • Function to ferry oxygen in blood to all cells of the body • RBCs differ from other blood cells because they are anucleate meaning they lack a nucleus and they also contain very few organelles (which also means they cannot divide) • Mature RBCs are literally sacs of hemoglobin molecules • Hemoglobin: iron-bearing protein, transports the bulk of the oxygen that is carried in the blood • In fact, because erythrocytes lack mitochondria and make ATP by anaerobic mechanisms, they do not use up any of the oxygen they transport, making them very efficient oxygen transporters indeed! • RBCs live about 120 days and are then phagocytized by the liver and spleen

12. Anemia & Sickle-Cell Anemia • Anemia: Decrease in the oxygen-carrying ability of the blood • May be result of: 1) Lower than normal number of RBCs 2) abnormal or deficient hemoglobin content in the RBCs or • Sickle-Cell Anemia (SCA): • The abnormal hemoglobin formed becomes spiky and sharp when the RBCs unload oxygen molecules or when the oxygen content of the blood is lower than normal (like during exercise, anxiety, or other stressful situations). • The deformed (crescent-shaped) erythrocytes rupture easily and dam up in small blood vessels. These events interfere with oxygen delivery and cause extreme pain. • It is amazing that this havoc results from a change in just ONE of the amino acids in each of the beta chains of the globin molecule! • SCA occurs chiefly in black people who live in the malaria belt of Africa and among their descendants….Apparently, the same gene that causes sickling makes RBCs infected by the malaria-causing parasite stick to the capillary walls and then lose potassium, an essential nutrient for survival of the parasite…Hence, the malaria-causing parasite is prevented from multiplying within the RBCs, and individuals with the sickle gene have a better chance of surviving where malaria is prevalent!!! Cool.

13. Leukocytes: “white blood cells” (WBCs) • Far less numerous than RBCs • Are crucial to body defense against disease • Include: Granulocytes (neutrophils, eosinophils, basophils) & Agranulocytes (lymphocytes, monocytes) • WBCs are the only complete cells in the blood; that is, they contain nuclei and the usual organelles • WBCs form a protective, movable army that helps defend the body against damage by bacteria, viruses, parasites, and tumor cells….so they have special characteristics…

14. More About Leukocytes (WBCs)… • RBCs are confined to the bloodstream and carry out their function in the blood…not WBCs… • WBCs are able to slip into and out of the blood vessels - a process called diapedesis. • The circulatory system is simply their means of transportation to areas of the body where their services are needed for inflammatory or immune responses (we will look more at this in ch.12) • WBCs can also locate areas of tissue damage and infection in the body by responding to certain chemicals that diffuse from the damaged cells (they “pick up the scent” and move there…pretty neat!) They pinpoint areas of tissue damage and rally round in large numbers to destroy microorganisms or dead cells. • Whenever WBCs mobilize for action, the body speeds up their production, and as many as twice the normal number of WBCs may appear in the blood within a few hours. A total WBC count above 11,000 cells/mm3 is referred to as leukocytosis….this generally indicates that a bacterial or viral infection is stewing in the body. Leukopenia, the opposite condition, is an abnormally low WBC count. It is commonly caused by certain drugs, such as corticosteroids and anticancer agents.

15. Leukocytosis & Leukemia • Leukocytosis: Normal and desirable response to infectious threats to the body. • By contrast, the excessive production of abnormal WBCs that occurs in infectious mononucleosis and leukemia is distinctly pathological. • Leukemia: • Literally “white blood” • The bone marrow becomes cancerous, and huge numbers of WBCs are turned out rapidly • Seems like not a bad thing….but….the “newborn” WBCs are immature and incapable of carrying out their normal protective functions. So, the body becomes the easy prey of disease-causing bacteria and viruses.

16. 2 Major Groups of WBCs: Granulocytes Granule containing Agranulocytes Lack visible granules Neutrophils Avid phagocytes at sites of acute infection Eosinophils Their number increases rapidly during allergies and infections by parasitic worms (like tapeworm) Basophils Rarest of WBCs that contain large histamine-containing granules Histamine is an inflammatory chemical that makes blood vessels leaky and attracts other WBCs to the inflammatory site. Lymphocytes Take up residence in lymphatic tissues, where they play an important role in the immune response Monocytes Largest of all WBCs They migrate into tissues, change into macrophages with huge appetites. Macrophages are very important in fighting chronic infections, such as tuberculosis

17. Platelets • Really aren’t cells…they are fragments of bizarre multinucleate cells called megakaryocytes which pinch off thousands of anucleate platelet “pieces” that quickly seal themselves off from the surrounding fluids • Platelets appear as darkly staining, irregularly shaped bodies scattered among the other blood cells • The normal platelet count in blood is about 300,000/mm3. • Platelets are needed for the clotting process that occurs in plasma when blood vessels are ruptured or broken

18. Hemostasis (hem=blood; stasis=standing still) • The process of stopping bleeding • Coagulation causes the formation of a blood clot • 3 Key Events: • 1. Blood vessel spasm - damaged or broken vessels stimulate muscle tissue in the walls of the blood vessels to contract. This slows or stops blood flow, lasts for several minutes. Also, platelets release serotonin, a vasoconstrictor which maintains the muscle spasm even longer. • 2. Platelet plug formation - platelets stick to surfaces of damaged blood vessels and to each other to form a "plug" • 3. Blood coagulation - most effective, forms a blood clot (hematoma). Injury causes an increase in the release of coagulants. Main event - conversion of fibrinogen into long protein threads called fibrin. • Blood clotting - Animation - YouTube

19. Undesirable Clotting: • Sometimes clots form in intact blood vessels, particularly in the legs • A clot that develops and persists in an unbroken blood vessel is called a thrombus • If large enough, it may prevent blood flow to the cells beyond the blockage…for example…if a thrombus forms in the blood vessels serving the hearth (coronary thrombosis), the consequences may be death of heart muscle and a fatal heart attack • If a thrombus breaks away from the vessel wall and floats freely in the bloodstream, it becomes an embolus. An embolus is usually no problem unless or until it lodges in a blood vessel too narrow for it to pass through…for example…a cerebral embolus may cause a stroke • A number of anticoagulants, most importantly aspirin, heparin, and dicumarol, are used clinically for thrombus-prone patients

20. Cool Picture from your Text…Reads: Fibrin Clot. Scanning electron micrograph of red blood cells trapped in a mesh of fibrin threads.

21. Blood Cell Formation (Hematopoiesis)

22. Blood Cell Formation • Occurs in red bone marrow • In adults, this tissue is found is found chiefly in the flat bones of the skull and pelvis, the ribs, sternum, and proximal epiphyses of the humerus and femur • Each type of blood cell is produced in different numbers in response to changing body needs and different stimuli…after they mature, they are discharged into the blood vessels surrounding the area. • All formed elements arise from a common type of stem cell: the hemocytoblast, which resides in the red bone marrow

23. Erythrocyte Development: • Because RBCs are anucleate (have no nucleus) they are unable to synthesize proteins, grow, or divide • As they age, RBCs become more rigid and begin to fragment, or fall apart, in 100-120 days. Their remains are eliminated by phagocytes in the spleen or liver. • Lost cells are replaced by the division of hemocytoblasts in the red bone marrow. • The developing RBCs divide many times and then begin synthesizing huge amounts of hemoglobin…suddenly when enough hemoglobin has been accumulated, the nucleus and most organelles are ejected and the cell collapses inward. • The result is the young RBC, called a reticulocyte because it still contains some rough endoplasmic reticulum (ER) • The reticulocytes enter the bloodstream to begin their task of transporting oxygen….within 2 days of release, they have ejected the remaining ER and have become fully functioning erythrocytes. • The entire developmental process from hemocytoblast to mature RBC takes 3-5 days.

24. Erythrocyte Development: • Rate of production is controlled by a hormone (not so surprisingly!) called erythropoietin • Normally a small amount of erythropoietin circulates in the blood at all times, and the red blood cells are formed at a fairly constant rate • Although the liver produces some, the kidneys play the major role in producing this hormone. • When blood levels of oxygen begin to decline for any reason, the kidneys step up their release of erythropoietin…the erythropoietin targets the bone marrow, prodding it into “high gear” to turn out more RBCs. • As you might expect, and overabundance of erythrocytes, or an excessive amount of oxygen in the bloodstream, decreases erythropoietin release and red blood cell production.

25. Leukocyte and Platelet Development • Also stimulated by hormones like erythrocytes • These “colony stimulating factors (CSFs)” and “interleukins” not only prompt red bond marrow to turn out leukocytes, but also marshal up an army of WBCs to ward off attacks by enhancing the ability of mature leukocytes to protect the body • They are released in response to specific chemical signals in the environment such as inflammatory chemicals and certain bacteria or their toxins • The hormone “thrombopoietin” accelerates the production of platelets, but little is known about how that process is regulated

26. Human Blood Groups

27. Antigens • Blood transfusions can save lives, but people have different blood groups, and transfusing incompatible or mismatched blood can be fatal • The plasma membranes of RBCs, like those of all body cells have genetically determined proteins (antigens), which identify each person as unique! • An antigen is a substance that the body recognizes as foreign; it stimulates the immune system to release antibodies or use other means to mount a defense against it

28. Antigens & Antibodies • Most antigens are foreign proteins like viruses or bacteria that have managed to invade the body • Each of us tolerates our own cellular (self) antigens, but one person’s RBC proteins will be recognized as foreign if transfused into another person with different RBC antigens • The “recognizers” are antibodies present in the plasma that attach to RBCs bearing surface antigens different form those on the patient’s RBCs

29. Antibodies and Agglutination • At this point of recognition of foreigner…binding of antibodies causes the RBCs to clump, called agglutination • This leads to clogging of small blood vessels throughout the body • During the next few hours, the foreign RBCs are ruptured and the hemoglobin is released into the blood stream • Although the transfused blood is unable to deliver the increased oxygen-carrying capacity hoped for and some tissue areas may be deprived of blood….the most devastating consequence…

30. Negative Consequences of Transfusion of Mismatched Blood • The most devastating consequence of severe transfusion reactions is that the freed hemoglobins block the kidney tubules and cause kidney failure • Transfusion reactions can also cause fever, chills, nausea, and vomiting, but in the absence of kidney shutdown these reactions are rarely fatal • Treatment is aimed at preventing kidney damage by infusing alkaline fluids to dilute and dissolve the hemoglobin and diuretics to flush it out of the body in urine

31. ABO and Rh Grouping • There are over 30 common RBC antigens in humans, allowing each person’s blood cells to be classified into different blood groups • However, it is the antigens of the ABO and Rh blood groups that cause the most vigorous transfusion reactions

32. ABO Blood Groups • Based on which of two antigens, type A or type B, a person inherits • Absence of both antigens results in type O blood • Presence of both antigens leads to type AB • Possession of type A gives type A blood and possession of type B gives type B blood • In the ABO blood group, antibodies are formed during infancy against the ABO antigens not present on your own RBCs • For example: a baby with neither the A nor the B antigen (O) forms both anti-A and anti-B antibodies, while those with type A antigens (A) form anti-B antibodies

33. Summary of ABO(from your text, pg.340) *Just remember, the antigens on the surface of your cells (or donated cells) will cause a reaction if your immune system does not recognize them as being part of you. Hence, if you are Type A, and transfused with Type B, your body will mobilize a massive immune response against the "invading" blood. This will cause coagulation of blood and death.

34. Rh blood groups • Named because 1 of the 8 Rh antigens was originally identified in Rhesus monkeys! • Later the same antigen was discovered in human beings • Most Americans are Rh+, meaning that their RBCs carry the Rh antigen…if you are negative, then you do not carry the Rh antigen • Unlike the antibodies of the ABO system, anti-Rh antibodies are not automatically formed and present in the blood of Rh- people. • However, if an Rh- person receives mismatched blood (Rh+), shortly after the transfusion his or her immune system becomes sensitized and begins producing antibodies (anti-Rh+) against he foreign blood type. • Hemolysis (rupturing of the RBCs) does not occur with the first transfusion because it takes time for the body to react and start making antibodies…however, the second time and every time after, a typical transfusion reaction occurs in which the patient’s antibodies attack and rupture the donor’s Rh+ RBCs

35. Important Rh Related Problem • Occurs in pregnant Rh- women that are carrying Rh+ babies • The first pregnancy usually results in the delivery of a healthy baby…but because the mother is sensitized by Rh+ antigens that have passed through the placenta into her bloodstream, she will form anti-Rh+ antibodies… • Unless she is treated with RhoGAM shortly after giving birth..RhoGAM is an immune serum that prevents this sensitization… • If she is not treated and becomes pregnant again with an Rh+ baby, her antibodies will cross through the placenta and destroy the baby’s RBCs, producing a condition known as “hemolytic disease of the newborn”. • The baby is anemic and becomes hypoxic (deficiency of oxygen) and cyanotic (the skin takes on a blue cast). Brain damage and even death may result unless fetal transfusions are done before birth to provide more RBCs for oxygen transport.

36. Blood Typing • The importance of determining the blood group of both the donor and the recipient BEFORE blood is transfused is glaringly obvious! • Essentially in blood typing, it involves testing the blood by mixing it with 2 different types of immune serum: anti-A and anti-B….Agglutination occurs when RBCs of a group A person are mixed with the anti-A serum, but not when they are mixed with the anti-B serum (& vise versa) • Because it is critical that blood groups be compatible, cross matching is also done….involves testing for agglutination of donor RBCs by the recipient’s serum and of the recipient's RBCs by the donor serum • Typing for Rh factors is done in the same manner as ABO blood typing

37. Blood Typing From your text…. Page 341

38. Today:1. Heart Labeling Quiz2. Complete PP Notes3. Disorders with Nooks Remember: Monday Heart Dissection!

39. Tracing the Flow of Blood through the Body (Chapter 11) Looking specifically at the heart, veins, and arteries

40. The Cardiovascular System • A closed system of the heart and blood vessels • The heart pumps blood • Blood vessels allow blood to circulate to all parts of the body • The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products

41. The Heart • Location • Thorax between the lungs • Pointed apex directed toward left hip • About the size of your fist

42. The Heart: Coverings • Pericardium – a double serous membrane that covers the heart like a bag, but has two layers with fluid in between… • Visceral pericardium • Next to heart • Parietal pericardium • Outside layer • Serous fluid fills the space between the layers of pericardium-reduces friction!

43. The Heart: Heart Wall • Three layers • Epicardium • Outside layer • This layer is the parietal pericardium • Connective tissue layer • Myocardium • Middle layer • Mostly cardiac muscle • Endocardium • Inner layer • Endothelium

44. Physiology of the Heart • As the heart beats or contracts, the blood makes continuous round trips-into and out of the heart, through the rest of the body, and then back to the heart-only to be sent out again • The amount of work that a heart does is almost too incredible to believe… • In one day it pushes the body’s supply of 6 quarts or so of blood (6Liters) through the blood vessels over 1,000 times! • Meaning that it actually pumps about 6,000 quarts (or liters) of blood every single day!

45. Blood Circulation • The systemic (to the body) and pulmonary (to the lungs) circuits are shown here • The left side of the heart is the systemic pump…supplies oxygen & nutrient rich blood to all body organs • The right side of the heart is the pulmonary circuit pump…receives relatively oxygen poor blood from the veins of the body and pumps it out to the lungs where oxygen is picked up and carbon dioxide is unloaded Figure 11.3

46. Path of Blood Through the HeartQuick OverviewGive Handout! 1. Deoxygenated blood enters right atrium through the vena cava2. Blood moves into the right ventricle3. Blood goes out the pulmonary arteries and heads to the lungs4. Blood returns from the lungs and enters the left atrium5. Blood moves into the left ventricle6. Oxygenated blood moves out of the left ventricle through the aorta and to the body

47. The Heart: Valves • Allow blood to flow in only one direction • Valves open as blood is pumped through • Held in place by chordae tendineae (“heart strings”) • Close to prevent backflow

48. The Heart: Valves • Four valves • Atrioventricular valves – between atria and ventricles • Bicuspid valve (left) • Tricuspid valve (right) • Semilunar valves between ventricle and artery • Pulmonary semilunar valve • Aortic semilunar valve

49. Sounds of the Heart • When using a stethoscope, you can hear two distinct sounds during each cardiac cycle • These heart sounds are often described by the two syllables “lub” and “dup”, and the sequence is lub-dup, pause, lub-dup, pause, etc… • The first sound “lub” is caused by the closing of the AV valves • The second sound “dup” is caused by the closing of the semilunar valves at the end of systole

50. The Heart: Associated Great Vessels • Aorta • Leaves left ventricle • Large vessel that delivers blood to the body • Pulmonary arteries • Leave right ventricle • Large vessel that splits into the left and right pulmonary arteries, these are the only arteries that carry deoxygenated blood • Vena cava • Enters right atrium • Superior Vena Cava - vessel the returns blood to the heart from the upper body • Inferior Vena Cava - vessel the returns blood to the heart from the lower body • Pulmonary veins (four) • Enter left atrium • Pulmonary Veins - returns oxygenated blood from the lungs