1. Cardiovascular System The Heart

2. Heart Facts
The cardiovascular system is composed of the heart and a closed system of vessels through which blood is circulated.
Hollow muscular organ
Tipped slightly so that a part of it sticks out and taps against the left side of the chest (apex), which is what makes it seem as though it is located there.
During an average lifetime, the human heart will beat more than 2.5 billion times.
Beats over 100,000 times/day and 35 million times/year to pump blood around the body's 60,000 miles of blood vessels.
5 pints of blood pump throughout your entire body with one single heartbeat.

3. External Structure of the Heart
Layers
Edocardium (inner layer)
Epicardium (outer layer)
Myocardium (middle layer)
Pericardium - the protective membrane surrounding the heart
Coronary arteries – supply blood to the outside of the heart

4. External Structure

5. Internal Structure Septum Atria and ventricles
atria contract while the ventricles relax
ventricles contract while the atria relax.
Atrioventricular (AV) Valves
Bicuspid (Mitral) Valve – between left atria and ventricle
Tricuspid Valve – between right atria and ventricle
Semilunar (SL) Valves
Pulmonary SL Valve – between right ventricle and pulmonary artery
Aortic SL Valve – between left ventricle and aorta
Ventricular Septum - right and left ventricles are divided by a thick muscular wall
babies born with "hole in the heart“
Why problematic?
Septum

7. connect papillary muscles to AV valves
“heartstrings”

8. The Cardiac Cycle The events associated with one heartbeat.
A single cardiac cycle lasts 0.8 seconds
Described as the contraction and relaxation of the four heart chambers.
During relaxation, chambers fill with blood (diastole).
During contraction, chambers expel blood (systole).
Heart Sounds
The first heart sound (lubb)
occurs during ventricular contraction
when the tricuspid and bicuspid valves (AV valves) close.
The second heart sound (dubb)
occurs during ventricular relaxation
when the pulmonary and aortic valves (SL valves) close.

9. The walls of the left ventricle are thicker as it has to pump blood to all the tissues, compared to the right ventricle which only pumps blood as far as the lungs.
Septum

11. Blood Pressure
Blood moves through circulatory system from areas of high pressure to low pressure. (Contraction of the heart produces the pressure.)
Blood Pressure is a measurement of the force that blood exerts against the inner walls of arteries.
120/80 is normal = systole/diastole
systolic pressure - The maximum pressure during ventricular contraction; systolic pressure is the peak arterial pressure.
diastolic pressure - The lowest pressure of blood in the arteries during ventricular relaxation (diastole); the arterial pressure drops.

12. Blood Pressure vs. Distance From Left Ventricle

13. Conduction System
Heart muscle cells contract without stimulation from the nervous system in a continuous, rhythmic pattern.
Contraction is initiated by the sinoatrial (SA) node (pacemaker).
SA node is located in the right atrium
Cells of the SA node can reach threshold on their own
SA node initiates one action potential after another (~70-80 times/min)
Pathway of electrical impulse
Sinoatrial (SA) node
Atrioventricular (AV) node
Atrioventricular bundle (bundle of His)
Bundle branches
Purkinje fibers
There is a momentary delay as the ventricles fill before they contract

15. Electrocardiograms (ECG / EKG)
A recording of the electrical changes that occur within
the myocardium as the
heart contracts.
R vent cont
L vent cont
R atr cont

16. Electrocardiograms (ECG / EKG)
Atria repolarized
Ventricle depolarized
Heart relaxed
Ventricular walls
repolarize
AV node and
walls depolarize
Atrial walls
completely
depolarized
Atria repolarizes
Ventricle
depolarizes

18. Cardiomyopathies Heart Valves
Stenosed Valves – valves that are narrower than normal, slowing blood flow from heart chamber
Rheumatic Heart Disease – delayed inflammatory response to streptococcal infection that occurs most often in children; valves become inflammed
Mitral Valve Prolapse (MVP) – affects bicuspid or mitral valve; flaps of valve extend back into the left atrium causing the valve to leak; asymptomatic or pain and fatigue
Aortic Regurgitation – blood ejects into aorta and regurgitates back into left ventricle due to leaky aortic SL valve; ventricle becomes too full and can cause MI

19. Cardiomyopathies Myocardium
Coronary Artery Disease (CAD) – One of leading causes of death in US; reduced blood flow to myocardial tissue; occlusion causes cells deprived of oxygen and eventually die
Heart Attack
Myocardial Infarction (MI)
myocardial = heart muscle tissue
infarction = tissue death due to oxygen starvation
A blood clot completely blocks a coronary artery (or one of its branches), cutting off oxygen supply to that part of the heart. This results in cardiac tissue death.
Atherosclerosis – hardening of the arteries due to fatty build up
Angina pectoris – myocardium deprived of oxygen causing severe chest pain; warning that coronary arteries can not supply heart with necessary oxygen
Coronary Bypass Surgery – treatment for coronary artery blood flow constriction; veins are harvested from other areas of body and used to bypass blockages
Congestive Heart Failure (CHF) – “left-side heart failure”; inability of left ventricle to pump blood effectively; could result from MI caused by CAD

20. Cardiomyopathies Arteries
Arteriosclerosis – hardening of the arteries causing blockage and weakening of the arterial walls; calcium deposits form; painful and life threatening
Ischemia – decreased blood supply to tissue; gradual cell death
Necrosis – tissue death
Gangrene – necrosis that has progressed to having decomposing bacteria
Angioplasty – procedure to mechanically open the affected area of an artery like in atherosclerosis patients; catheter inserts balloon to inflate and push out plaque; stents can be inserted to keep artery open
Aneurysm – arterial wall damage due to arteriosclerosis or other factors; section of artery abnormally widened because of weak arterial wall; causes clot formation that travels (thrombus) that can cause an embolism (blockage) in the heart; tendency to burst resulting in death
Cerebrovascular Accident (CVA) aka Stroke – results from brain tissue ischemia caused by an embolism or ruptured aneurism; effects range from hardly noticeable to crippling effects

21. Balloon Angioplasty

22. Cardiomyopathies Veins
Varicose Veins – enlarged veins where blood tends to pool rather than continuing to the heart; occur in superficial veins
Hemorrhoids – varicose veins in the anal canal due to excessive straining
Phlebitis – vein inflammation
Thrombophlebitis – acute phlebitis caused by a thrombus; pain and discolored tissue
Pulmonary Embolism – embolus lodged in lung; death quickly

23. Heart Attack
In this illustration, a clot is shown in the location of #1. Area #2 shows the portion of the damaged heart that is affected by the clot.
Heart Attack Animation

24. Heart Transplant

25. The surgeon will begin by exposing the chest cavity through a cut in the ribcage. The surgeon will then open the pericardium (a membrane that covers the entire heart) in order to remove your diseased heart. The back part of your own left atrium will be left in place, but the rest of the heart will be removed.

26. Your new heart will be carefully trimmed and sewn to fit the remaining parts of your old heart. This transplant method is called an "Orthotopic procedure". This is the most common method used to transplant hearts.
You will be given medications both before and during the operation to prevent you from rejecting the new heart.

27. Live heart to be transplanted into patient