1. The Heart ~ size of fist mass 250-350 grams (< 1 lb)
4 chambers/double pump

2. Pericardium – double walled sac that encloses the heart
-protects
-anchors
-prevents overfilling
-prevents friction

3. Four Chambered Heart
2 Atria are the receiving chambers returning to the heart from circulation
Right atrium receives deoxygenated blood from the body
Left atrium receives oxygenated blood from the lungs

4. Four Chambered Heart
2 Ventricles are the discharging chambers returning blood to circulation
Right ventricle pumps deoxygenated blood to the lungs (pulmonary circulation)
Left ventricle pumps oxygenated blood to the body (systemic circulation)

7. Physiology of the Heart Beat
The Intrinsic (In-House) Conduction System of the Heart consists of autorythmic cells found in the following areas of the heart
Sinoatrial node
Atrioventricular node
Atrioventricular bundle
Right and Left Bundle Branches
Purkinje fibers

8. Sinoatrial (SA) Node
The heart’s pacemaker – it is a small mass of autorhythmic cells that generate impulses ~ 75 times per minute
This sinus rhythm determines heart rate

10. Atrioventricular (AV) Node
Impulse from SA node travel via the internodal pathway causing both the right and left atria to contract
Tricuspid and Mitral valves are open
The impulse pauses at the AV node (~.1 seconds) – atria contraction completed

11. Atrioventricular (AV) Node
Impulse travels from atrioventricular node to the right and left bundle branches to the Purkinje fibers located in the walls of the ventricles
Mitral and Tricuspid valves close and the Pulmonary and Aortic valves open while the right and left ventricles contract

13. Mechanical Events of Cardiac Cycle
Diastole – heart chamber relaxation period
Systole – heart chamber contraction period

14. Mechanical Events of Cardiac Cycle
Phase 1 – Ventricular filling
Tricuspid and Mitral Valves are open
Atria contract forcing residual blood into ventricles (P wave of electrocardiogram –ECG)

15. Mechanical Events of Cardiac Cycle
Phase 2 – Ventricular systole
Atria relax and Tricuspid and Mitral valves close (QRS complex of ECG) – isovolumetric contraction phase
Pulmonary and Aortic valves open and ventricles contract (T wave of ECG follows)

16. Mechanical Events of Cardiac Cycle
Phase 3 – Isovolumetric relaxation – all valves are closed and ventricles are relaxed

17. Electrocardiogram (ECG or EKG)
a test that checks for problems with the electrical activity of your heart. An ECG translates the heart's electrical activity into line tracings on paper.

19. http://player. discoveryeducation. com/index. cfm

20. Blood Vessels

22. Blood Vessels Elastic (Conducting) Arteries 1.5 cm
Muscular (Distributing) Arteries 6.0 mm
Arterioles µm lumen diameter
Capillary 9.0 µm lumen diameter
Venule µm lumen diameter
Vein 5 mm lumen diameter

23. Artery

24. Vein

25. Capillary
Endothelial cells

27. Capillary Bed

28. Diffusion
Molecules moving from an area of high concentration to low concentration until equilibrium is met
Passive Transport – Diffusion across a cell membrane
Osmosis – Diffusion of water across a cell membrane

30. What types of molecules diffuse across cell membranes??

31. HUMAN CIRCULATION
Systemic Circulation – Body
Cranial Circulation – Brain
Pulmonary Circulation – Lungs
Coronary Circulation – Heart
Hepatic Portal Circulation – Intestines & Liver
Renal Circulation – Kidneys

33. Blood Pressure (BP)
The force per unit area exerted on a vessel wall by the contained blood measured in mm Hg.
Blood pressure refers to systemic arterial blood pressure in the largest arteries near the heart

34. Arterial Blood Pressure
Systolic Pressure/Diastolic Pressure
Systolic pressure – the peak arterial pressure reached after the ventricles contract
Diastolic pressure – the lowest arterial pressure reached when the ventricles are relaxed

35. Resistance
The opposition to flow - it is a measure of the amount of friction blood encounters as it passes through the vessels
Because most friction occurs well away from the heart the term peripheral resistance is generally used.

36. Sources of Resistance
Blood Viscosity – related to the thickness or “stickiness” of a fluid.
The higher the viscosity the more difficult it is to keep the fluid moving

37. Sources of Resistance
Total blood vessel length – the longer the vessel, the greater the resistance
An extra pound or two of fat requires miles of small blood vessels to service it

39. Sources of Resistance
Blood vessel diameter – small diameter arterioles, which enlarge or constrict in response to neural and chemical controls, are the major determinants of peripheral resistance.

40. Sources of Resistance
Blood flow becomes turbulent when it encounters rough or protruding areas of the tube wall (atherosclerosis)
Turbulence increases resistance

41. Atherosclerosis
Plaque build up in the lumen of blood vessels – may completely block blood flow

43. Effects of Chronic Hypertension

44. Negative Effects of Hypertension – High Blood Pressure on the body
Heart failure
Vascular disease
Renal failure
Stroke
Retinal damage

46. Measuring Blood Pressure
Sphygmomanometer – cuff used to measure blood pressure in brachial artery
Stethoscope –used to hear a heart beat