1. EDU2HBS Human Body Systems 1 Cardiovascular System

2. EDU2HBS Human Body Systems 2

3. 3 The Cardiovascular System A closed system of the heart, blood 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

4. EDU2HBS Human Body Systems 4  Color range  pH must remain between 7.35–7.45  Blood temperature is slightly higher than body temperature The Blood ( Physical Characteristics)

5. EDU2HBS Human Body Systems 5 Blood Plasma  Includes many dissolved substances  Nutrients  Salts (metal ions)  Respiratory gases  Hormones  Proteins  Waste products

6. EDU2HBS Human Body Systems 6 Erythrocytes (Red Blood Cells)  Outnumber white blood cells 1000:1  Contain a protein chemical called hemoglobin  Make blood bright red  Contains the element iron which carries oxygen

7. EDU2HBS Human Body Systems 7 Leukocytes (White Blood Cells) Platelets  occurs when blood vessels are ruptured.

8. EDU2HBS Human Body Systems 8 The Heart  Location  Thorax between the lungs  Pointed apex directed toward left hip  About the size of your fist

9. EDU2HBS Human Body Systems 9 The Heart: Coverings  Pericardium – a double walled membrane  Visceral pericardium  Parietal pericardium  Serous fluid fills the space between the layers of pericardium

10. EDU2HBS Human Body Systems 10 The Heart: Heart Wall  Three layers  Epicardium  Outside layer  This layer is the parietal pericardium  Myocardium  Middle layer  Endocardium  Inner layer

11. EDU2HBS Human Body Systems 11 External Heart Anatomy

12. EDU2HBS Human Body Systems 12 The Heart: Chambers  Four chambers  Atria  Receiving chambers  Right atrium  Left atrium  Ventricles  Discharging chambers  Right ventricle  Left ventricle

13. EDU2HBS Human Body Systems 13 Blood Circulation

14. EDU2HBS Human Body Systems 14 The Heart: Valves  Four valves  Atrioventricular valves – between atria and ventricles  Mitral valve (left)  Tricuspid valve (right)  Semilunar valves between ventricle and artery  Pulmonary semilunar valve  Aortic semilunar valve

15. EDU2HBS Human Body Systems 15 The Heart: Valves  Valves open as blood is pumped through  Close to prevent backflow

16. EDU2HBS Human Body Systems 16 Coronary Circulation  The heart has its own nourishing circulatory system  Coronary arteries  Cardiac veins  Blood empties into the right atrium via the coronary sinus

17. EDU2HBS Human Body Systems 17 The Heart: Conduction System  Intrinsic conduction system (nodal system)  Heart muscle cells contract, without nerve impulses, in a regular, continuous way

18. EDU2HBS Human Body Systems 18

19. EDU2HBS Human Body Systems 19 Heart Contractions  Sequential stimulation occurs at other autorhythmic cells  AV node  AV bundle  Bundle branches  Purkinje fibres

20. EDU2HBS Human Body Systems 20 The Heart: Cardiac Output  Cardiac output (CO)  CO = (heart rate [HR]) x (stroke volume [SV])  Stroke volume

21. EDU2HBS Human Body Systems 21 The Heart: Regulation of Heart Rate  Starling’s law of the heart – the more that the cardiac muscle is stretched, the stronger the contraction  Changing heart rate is the most common way to change cardiac output

22. EDU2HBS Human Body Systems 22 The Heart: Regulation of Heart Rate Increased heart rate  Sympathetic nervous system  Crisis  Low blood pressure  Hormones  Epinephrine  Thyroxine  Exercise  Decreased blood volume

23. EDU2HBS Human Body Systems 23 The Heart: Regulation of Heart Rate Decreased heart rate  Parasympathetic nervous system  High blood pressure or blood volume  Decreased venous return

24. EDU2HBS Human Body Systems 24 Blood Vessels: The Vascular System  Taking blood to the tissues and back  Arteries  Arterioles  Capillaries  Venules  Veins

25. EDU2HBS Human Body Systems 25 Differences Between Blood Vessel Types  Walls of arteries are the thickest  Lumens of veins are larger  Walls of capillaries are only one cell layer thick to allow for exchanges between blood and tissue

26. EDU2HBS Human Body Systems 26 Movement of Blood Through Vessels  Most arterial blood is pumped by the heart  Veins use the milking action of muscles to help move blood Figure 11.9

27. EDU2HBS Human Body Systems 27 Capillary Beds  Capillary beds consist of two types of vessels 1. Vascular shunt – directly connects an arteriole to a venule

28. EDU2HBS Human Body Systems 28 Capillary Beds 2. True capillaries – exchange vessels  Oxygen and nutrients cross to cells  Carbon dioxide and metabolic waste products cross into blood Figure 11.10

29. EDU2HBS Human Body Systems 29 Pulse  Monitored at “pressure points” where pulse is easily palpated

30. EDU2HBS Human Body Systems 30 Blood Pressure  Pressure in blood vessels decreases as the distance away from the heart increases

31. EDU2HBS Human Body Systems 31 Blood Pressure: Effects of Factors  Neural factors  Autonomic nervous system adjustments (sympathetic division)  Renal factors  Regulation by altering blood volume  Renin – hormonal control

32. EDU2HBS Human Body Systems 32 Blood Pressure: Effects of Factors  Temperature  Heat has a vasodilation effect  Cold has a vasoconstricting effect  Chemicals  Various substances can cause increases or decreases  Diet

33. EDU2HBS Human Body Systems 33 Factors Determining Blood Pressure

34. EDU2HBS Human Body Systems 34 Variations in Blood Pressure  Human normal range is variable  Normal  140–110 mm Hg systolic  80–75 mm Hg diastolic  Hypotension  Low systolic (below 110 mm HG)  Often associated with illness  Hypertension  High systolic (above 140 mm HG)  Can be dangerous if it is chronic