1. Cardiovascular
System

2. The Cardiovascular System: The Heart
Heart pumps over 1 million gallons per year
Over 60,000 miles of blood vessels

3. Functions Transport oxygen & carbon dioxide to and from tissues
Transports nutrients, waste products, and hormones
Regulates body temperature
Plays a role in the immune response

4. Important Facts
A healthy adult heart pumps about 5 liters of blood out per minute.
During vigorous exercise, the amount of blood pumped out of the heart per minute drastically increases.
If the heart stops contracting, blood flow throughout the body stops.
If the heart stops functioning for a few minutes life will end.

5. Circulation Heart is two pumps in one!!!
Pulmonary —right side of heart forcing blood to flow to the lungs and back to the left side of the heart
Systemic —left side of heart forces blood to flow to all other tissues in the body and back to the right side of the heart

6. Circulation
Circulation

7. Size, Form, and Location of Heart
Shaped like a blunt cone
About the size of a closed fist
In thoracic cavity between the lungs
Apex —blunt, rounded point; most inferior part of heart
Base —larger, flat portion; directed superiorly and slightly posteriorly

8. Anatomy of the Heart
Pericardium —double layered, closed sac that surrounds the heart
Pericardial cavity —space around the heart
Filled with a thin layer of pericardial fluid—helps reduce friction as the heart moves within the pericardial sac

9. Layers of Heart Wall Epicardium Myocardium Endocardium
visceral layer of serous pericardium
Myocardium
cardiac muscle layer is the bulk of the heart
Endocardium
chamber lining & valves

10. Concept Check
About how big is your heart? What is the inferior portion called? The superior?
How many miles of blood vessels does your body contain?
What are the two types of circulation the heart does?
What are the functions of the circulatory system?
What are the three layers of the heart?
What surrounds the heart in the body?

11. Myocardial Thickness and Function
Thickness of myocardium varies according to the function of the chamber
Atria are thin walled, deliver blood to adjacent ventricles
Ventricle walls are much thicker and stronger
right ventricle supplies blood to the lungs (little flow resistance)
left ventricle wall is the thickest to supply systemic circulation

12. Thickness of Cardiac Walls
Myocardium of left ventricle is much thicker than the right.

13. External Anatomy of Heart
Superior/Inferior Vena Cava —carry blood from body to right atrium
Pulmonary veins —carry blood from lungs to left atrium
Pulmonary arteries —carry blood from heart to the lungs
Aorta —carry blood from the heart to the rest of the body

15. Heart Chambers Atria—2 upper chambers Ventricle—2 lower chambers
Receives blood from veins
Contraction of atria forces blood into ventricles
Ventricle—2 lower chambers
Pump blood out of the heart into arteries
Left is thicker than right
Septum—separates heart into right and left sections

16. Aorta
Superior
Vena Cava
Left atrium
Right atrium
Septum
Left ventricle
Right ventricle

17. Heart Valves
Atrioventricular valves—located between atria and ventricles
Prevent blood from backflow into atrium
Tricuspid valve—between right atrium & right ventricle
Bicuspid (mitral) valve—between left atrium & left ventricle
bicuspid
tricuspid

18. Heart Valves
Aortic semilunar valve—blood flow from left ventricle to aorta
Prevents backflow
Pulmonary semilunar valve—blood flow from right ventricle to pulmonary trunk

20. Path of Blood Through Heart
Enters through Superior/Inferior Vena Cava—Right atrium—tricuspid valve—Right ventricle—pulmonary semilunar valve—pulmonary arteries—lungs—Left atria—bicuspid valve—left ventricle—aortic semilunar valve—aorta

22. Conduction System of Heart
SA node
cluster of cells in wall of Rt. Atria
begins heart activity that spreads to both atria
excitation spreads to AV node
AV node
in atrial septum, transmits signal to bundle of His
AV bundle of His
the connection between atria and ventricles
divides into bundle branches & purkinje fibers, large diameter fibers that conduct signals quickly

23. Electrocardiogram---ECG or EKG
Action potentials of all active cells can be detected and recorded
P wave
atrial depolarization
P to Q interval
conduction time from atrial to ventricular excitation
QRS complex
ventricular depolarization
T wave
ventricular repolarization

24. Conduction of the Heart
Fibrillation—heart acting as a lot of pacemakers causing the heart to contract rapidly
Reduces the output of the heart by only a few milliliters of blood per minute when it occurs in the ventricles—these needs to stop quickly before death sets in
Defibrillation—a strong electrical shock is applied to the chest region
Trying to cause heart to go back into normal fibrillation

25. Auscultation Stethoscope
Sounds of heartbeat are from turbulence in blood flow caused by valve closure
first heart sound (lubb) is created with the closing of the atrioventricular valves
second heart sound (dupp) is created with the closing of semilunar valves

26. Blood Pressure Systole—contraction of the ventricles
Atria are relaxed allowing blood to collect
Immediately atrioventricular valves closes
Once pressure builds beyond pressure in aorta and pulmonary trunk, blood is forced into pulmonary trunk and aorta
Diastole—relaxation of the ventricles
Atria contract allowing blood to flow into ventricles
Ventricular pressure decreases
Semilunar valves close

27. Exercise and the Heart
Sustained exercise increases oxygen demand in muscles.
Benefits of aerobic exercise (any activity that works large body muscles for at least 20 minutes, preferably 3-5 times per week) are;
increased cardiac output
increased HDL and decreased triglycerides
improved lung function
decreased blood pressure
weight control.

28. Congestive Heart Failure
Causes of CHF
coronary artery disease, hypertension, MI, valve disorders, congenital defects
Left side heart failure
less effective pump so more blood remains in ventricle
heart is overstretched & even more blood remains
blood backs up into lungs as pulmonary edema
suffocation & lack of oxygen to the tissues
Right side failure
fluid builds up in tissues as peripheral edema

29. Risk Factors for Heart Disease
Risk factors in heart disease:
high blood cholesterol level
high blood pressure
cigarette smoking
obesity & lack of regular exercise.
Other factors include:
diabetes mellitus
genetic predisposition
male gender
high blood levels of fibrinogen
left ventricular hypertrophy

30. Coronary Artery Disease
Heart muscle receiving insufficient blood supply
narrowing of vessels---atherosclerosis, artery spasm or clot
atherosclerosis--smooth muscle & fatty deposits in walls of arteries
Treatment
drugs, bypass graft, angioplasty, stent

31. Clinical Problems MI = myocardial infarction Blood clot
death of area of heart muscle from lack of O2
replaced with scar tissue
results depend on size & location of damage
Blood clot
use clot dissolving drugs streptokinase or t-PA & heparin
balloon angioplasty
Angina pectoris----heart pain from ischemia of cardiac muscle

32. By-pass Graft

33. Stent in an Artery
Maintains patency of blood vessel

35. Cardiac Cycle
Repetitive pumping process that begins with the onset of cardiac muscle contraction and ends with the beginning of the next contraction
Pressure changes—Blood moves from areas of high pressure to low pressure
Blood Pressure
Systole
Diastole

36. Abnormal Heart Sounds Called murmurs
Result of faulty valves—valve doesn’t close tightly allowing blood to enter
Makes a swishing sound immediately after closure of the valve
Example: incompetent bicuspid valve makes a swishing sound after first heart sound

37. Regulation of Heart Function
Cardiac output— volume of blood pumped by either ventricle of the heart each minute
Cardiac output= stroke volume x heart rate
Stroke volume— the volume of blood pumped per ventricle each time the heart contracts
Heart rate— the number of times the heart contracts each minute