1. Cardiovascular System – Pulmonary and Systemic Circuits

2. 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

4. Heart Location

5. Coverings of the Heart Pericardium Make up the pericardial cavity
Fibrous pericardium
Protects and anchors heart
Parietal pericardium and Visceral pericardium
Make up the pericardial cavity
Pericardial fluid reduces friction

6. Walls of the Heart Epicardium Myocardium Endocardium
Same as visceral pericardium
Lubricates heart
Myocardium
Layer that contracts
Endocardium
Lines heart chambers

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

8. Heart Valves Atrioventricular valves Semilunar valves Chordae tendinae
Tricuspid – right
Three flaps
Bicuspid (mitral) – left
Two flaps
Semilunar valves
Pulmonary – right
Aortic – left
Chordae tendinae
Anchor AV valve flaps

9. Blood Supply to the Heart
Coronary arteries
Branch from aorta and nourish heart muscle
Cardiac veins
Drain blood from heart muscle into the coronary sinus then into right atrium.

11. Cardiac Cycle
Cardiac cycle – series of events that constitute a complete heartbeat
Systole – contraction
Prior to atrial systole 70% of blood follows into ventricles without contraction
Diastole – relaxation

12. Cardiac Cycle Heart Sounds – “lub-dup” Lub – ventricular systole
AV valves close
Dup – ventricular diastole
SL valves close
Murmur – irregular heart sound
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13. 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

14. 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

15. 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
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16. 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

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

18. Blood Vessels

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

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

21. Capillaries Smallest diameter blood vessels
Extensions of inner lining of arterioles (tunica intima)
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

22. 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

24. 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 ( )
Decreases during ventricular diastole – diastolic pressure (70-90)
Pulse
Heart Transplant Technology Video

25. 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
Emotions, exercise, hormones & pain