1. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Cardiovascular System  A closed system of the heart and blood vessels  function - transportation - oxygen, nutrients - carbon dioxide, wastes - heat, hormones - defensive cells

2. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Circulation Figure 11.3

3. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Vessels: The Vascular System  Taking blood to the tissues and back  Arteries  Arterioles  Capillaries  Venules  Veins Figure 11.8a

4. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Vascular System Figure 11.8b  Three layers: endothelium, middle, outer layer  Middle layer is smooth muscle

5. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Capillary Exchange  Fluid forced out by blood pressure  Plasma proteins,blood cells retained in blood  Osmotic pressure brings fluid back into capillary  Excess tissue fluid collected into lymphatic system, returned to blood

6. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Capillary Exchange: Mechanisms  Direct diffusion across plasma membranes  Endocytosis or exocytosis  intercellular slits = gaps  Plasma membrane not joined by tight junctions  Pores

7. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Vessels  Venous system  three layers, thin-walled  carry blood toward the heart  Mechanisms in blood return  Contraction of skeletal muscles  One-way valves  Pressure changes associated with breathing

8. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Arterioles and Capillaries Figure 8.2

9. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart Figure 11.1 Fist-sized; placed between lungs

10. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart: Heart Wall  Three layers  Epicardium  visceral pericardium  Connective tissue layer  Myocardium  Mostly cardiac muscle  Endocardium  Endothelium

11. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart: Chambers  Right and left side act as separate pumps  Four chambers  Atria  Receiving chambers  Right atrium  Left atrium  Ventricles  Discharging chambers  Right ventricle  Left ventricle Figure 11.2c

12. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart: Associated Great Vessels  Aorta  Leaves left ventricle  Pulmonary arteries  Leave right ventricle  Vena cava  Enters right atrium  Pulmonary veins (four)  Enter left atrium

13. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart: Valves  Allow blood to flow in only one direction  Four valves  Atrioventricular valves – between atria and ventricles  Semilunar valves between ventricle and artery  Valves open as blood is pumped through  AV held in place by chordae tendineae (“heart strings”)  Close to prevent backflow

14. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Operation of Heart Valves Fig 11.4

15. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart Figure 8.8

16. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings External Heart Anatomy Figure 11.2a

17. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart: Conduction System  Intrinsic conduction system (nodal system)  Heart muscle cells contract, without nerve impulses, in a regular, continuous way

18. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart: Conduction System  Special tissue sets the pace  Sinoatrial node  Pacemaker  Atrioventricular node  Atrioventricular bundle

19. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Filling of Heart Chambers – the Cardiac Cycle Figure 11.6

20. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Cycle Figure 8.12

21. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Electrocardiograms (EKG/ECG) Figure 8.15b,c

22. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart: Cardiac Output  Cardiac output (CO)  Amount of blood pumped by each side of the heart in one minute  CO = (heart rate [HR]) x (stroke volume [SV])  Stroke volume  Volume of blood pumped by each ventricle in one contraction

23. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Heart: Regulation of Heart Rate  Decreased heart rate  Parasympathetic nervous system  High blood pressure or blood volume  Decreased venous return

24. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cardiac Output Regulation Figure 11.7

25. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Pulse  Pulse – pressure wave of blood  Monitored at “pressure points” where pulse is easily palpated Figure 11.16

26. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Measuring Arterial Blood Pressure Figure 11.18  Systolic – pressure at the peak of ventricular contraction  Diastolic – pressure when ventricles relax

27. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Regulation of the Cardiovascular System: Baroreceptors  Baroreceptors: pressure receptors in aorta and carotid arteries  Steps in mechanism  Blood pressure rises, vessels stretched  Signals sent to brain in the cardiovascular center  Heart signaled to lower heart rate and force of contraction  Arterioles vasodilate, increasing blood flow to tissues  Combined effect lowers blood pressure

28. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Regulation of the Cardiovascular System: Nervous and Endocrine Factors  Medulla oblongata signals  Sympathetic nerves: constrict blood vessels, raising blood pressure  Parasympathetic nerves: dilate blood vessels, lowering blood pressure  Hormones: epinephrine (adrenaline)  Local requirements dictate local blood flow

29. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Pressure: Effects of Factors  Neural factors  Autonomic nervous system adjustments (sympathetic division)  Renal factors (kidneys)  Regulation by altering blood volume  Renin – stimulates hormonal control

30. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Blood Pressure: Effects of Factors  Temperature  Heat - vasodilation effect  Cold - vasoconstricting effect  Chemicals  Various substances can cause increases or decreases  Diet

31. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Variations in Blood Pressure Normal range is variable  140–110 mm Hg systolic  80–75 mm Hg diastolic  Hypotension  Low systolic (below 100 mm HG)  Often associated with illness  Hypertension  High systolic (above 140 mm HG)  Can be dangerous if it is chronic

32. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

33. Atherosclerosis  Buildup of plaques on inner wall of arteries  Source - injury from chemicals, physical blow or pressure. injured cells attract lipid deposits, muscle cells which block lumen of vessel Arteriosclerosis - hardening, loss of elasticity in wall as cells die, fibers degenerate, rigid scar tissue replaces elastic cells.

34. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cardiovascular Disorders  Angina pectoris: a warning  Myocardial infarction/heart attack: permanent cardiac damage  Congestive heart failure: decrease in pumping efficiency  Embolism: blockage of blood vessels  Stroke: impaired blood flow to the brain

35. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Reducing the Risk of Cardiovascular Disease  Smoking: don’t  Blood lipids: monitor cholesterol levels  Exercise: regular and moderate  Blood pressure: treat hypertension  Weight: being overweight increases risk of heart attack and stroke  Control of Diabetes Mellitus: early diagnosis and treatment delays onset of related problems  Stress: avoid chronic stress