1. Cardiovascular System

2. Characteristics of Blood Connective tissue Plasma and cells Transports substances between body cells and the external environment

3. Blood Volumes Varies with body size, fluid and electrolyte concentrations, and amount of adipose Average adult volume – 5 liters (4-5 L for women, 5-6 L for men) Hematocrit – usually 45%

4. Blood Cell Types Erythrocytes – RBCs Leukocytes – WBCs Thrombocytes - platelets

5. Red Blood Cells (RBCs) Biconcave disks that thin near the centers  increased surface area for transporting gases Have nuclei early in development, but extrude them No nucleus – more room for hemoglobin, but cannot reproduce or make proteins

6. Hemoglobin Oxygen-carrying protein 1/3 of each RBC Gives blood its color Oxyhemoglobin Deoxyhemoglobin Hypoxia Cyanosis

7. Red Blood Cell Counts RBCC – the number of RBCs in 1 mm 3 of blood Adult male average – 4.6 – 6.2 million Adult female average – 4.2 – 5.4 million Determines blood’s oxygen carrying capacity Important diagnostic tool

8. Blood Cell Production RBCs are normally flexible, elastic, and able to pass through small blood vessels More fragile as they age Macrophages phagocytize and destroy damaged RBCs in the liver and spleen

9. Breakdown of Hemoglobin

11. White Blood Cells (WBCs) Function to protect against disease –Phagocytize bacterial cells –Produce antibodies Move by diapedesis 2 main types: –Granulocytes – neutrophils, eosinophils, and basophils –Agranulocytes – monocytes and lymphocytes

13. Granulocytes Lobed nucleus with 2- 5 sections Dark staining nucleus and pale granules 54-62% of WBCs Contain many lysosomes – actively phagocytizes bacteria

14. Granulocytes Contains coarse, uniformly sized granules 2 lobes on nucleus Stains red 1-3% of WBCs Kills parasites Helps control inflammation and allergic reactions

15. Granulocyte Fewer, more irregular granules than eosinophils Granules stain deep blue Less than 1% of WBCs Contain heparin (inhibits blood clotting) and histamine (increases blood flow to injured tissues)

16. Agranulocytes Largest blood cells May live weeks  months 3-9% of WBCs Discussed later

17. Agranulocyte Form in red bone marrow and lymphatic system Slightly larger than RBCs Large, round nucleus with rim of cytoplasm May live for years 25-33% of WBCs Discussed more later

18. White Blood Cell Count (WBCC) Number of WBCs in 1 mm 3 of blood Adult average – 5000 – 10,000 cells Leukocytosis Leukopenia Differential WBCC (DIFF) –More neutrophils – bacterial infection –More eosinophils – parasitic infection, allergic reaction Leukemia

19. Platelets Not complete cells Form from megakaryocytes that fragment Lack nuclei Half size of RBCs Live 10 days Average count – 130,000 – 360,000 cells Help close breaks in damaged blood vessels Initiate formation of blood clots

20. Plasma 92% water Functions include: –Transporting nutrients, gases, and vitamins –Regulating fluid and electrolyte balance –Maintaining pH

21. Plasma Proteins

22. Hemostasis Vasospasm Platelet plug formation Coagulation Fibroblasts invade clot

23. Hemostasis

24. Blood Groups ABO blood group is based on the presence or absence of 2 major antigens (RBC surface molecules) 4 possible combinations: –A–A –B–B –AB –O–O

26. Rh Blood Group

27. Cardiovascular System – Pulmonary and Systemic Circuits

28. System Overview System consists of the heart and the blood vessels Function: to bring oxygen and nutrients to all body cells and to remove waste

30. Heart Location

31. Coverings of the Heart Pericardium –Fibrous pericardium –Parietal pericardium –Visceral pericardium Pericardial cavity Pericardial fluid reduces friction

32. Walls of the Heart Epicardium Myocardium Endocardium –Purkinje fibers

33. Heart Chambers 4 chambers of the heart –Atria Thin walls Receive blood returning to the heart Auricles –Ventricles Thicker walls Receive blood from atria Force blood out of heart Septum

35. Heart Valves Atrioventricular valves –Tricuspid – right –Bicuspid – left Semilunar valves –Pulmonary – right –Aortic – left Chordae tendinae Papillary muscles

37. Blood Supply to the Heart Coronary arteries Cardiac veins Coronary sinus

41. Cardiac Cycle Cardiac cycle – series of events that constitute a complete heartbeat Systole – contraction Diastole – relaxation

42. Cardiac Cycle Heart Sounds – “lub- dup” Lub – ventricular systole –AV valves close Dup – ventricular diastole –SL valves close Murmur

43. Cardiac Conduction System Coordinates the events of the cardiac cycle Consists of clumps and strands of specialized cardiac muscle that initiate and distribute impulses throughout the myocardium

44. Nodes of Cardiac Conduction System Sinoatrial node – AKA “pacemaker” –Just beneath epicardium –Located in right atrium near opening of superior vena cava –Initiates impulses without nervous stimulation

45. Nodes of Cardiac Conduction System Atrioventricular node –Located in inferior portion of septum AV bundle (bundle of His) –Large fibers run through the interventricular septum Purkinje fibers –Spread from septum into papillary muscles –Stimulate ventricular contraction

47. Regulation of Cardiac Cycle Parasympathetic and sympathetic fibers from medulla oblongata run to the nodes –Secrete acetylcholine to decrease heart rate –Secrete norepinephrine to increase heart rate Cardiac center

48. Electrocardiogram (ECG) Recording of the electrical changes in the myocardium during the cardiac cycle P – atrial systole QRS – ventricular systole; covers atrial diastole T – ventricular diastole

49. Blood Vessels

50. Arteries Strong, elastic vessels that carry blood away from the heart Lead to finer branches called arterioles

51. Artery Layers Tunica interna – simple squamous epithelium for smooth surface Tunica media – largest layer; smooth muscle and elastic CT Tunica externa – CT that attaches artery to surrounding tissues

52. Capillaries Smallest diameter blood vessels Extensions of inner lining of arterioles Connect arterioles and venules Allow exchange between blood and tissue fluid More abundant around muscles and nerves Blood flow controlled by precapillary sphincters Exchanges occur by diffusion, osmosis, and filtration

53. Veins Carry blood back to the right atrium of the heart Form from microscopic venules that are continuous with capillaries Structure similar to arteries, but less developed tunica media Many have valves to prevent blood backflow Act as blood reservoirs when hemorrhage causes decrease in arterial blood pressure

55. Blood Pressure The force blood exerts against the inner walls of blood vessels Refers primarily to arterial blood pressure Increases during ventricular systole – systolic pressure (100-140) Decreases during ventricular diastole – diastolic pressure (70-90) Pulse

56. Factors that Affect Blood Pressure Heart action – how much blood enters arteries Blood volume Peripheral resistance – friction between blood and vessels Blood viscosity Hypertension and stroke