1. Cardiovascular System: The Heart
Chapter 11

2. Put your hand on your heart
Put your hand on your heart. Did you place your hand on the left side of your chest? Many people do, but the heart is actually located almost in the center of the chest, between the lungs. It's tipped slightly so that a part of it sticks out and taps against the left side of the chest, which is what makes it seem as though it is located there.
Hold out your hand and make a fist. If you're a kid, your heart is about the same size as your fist, and if you're an adult, it's about the same size as two fists.
Your heart beats about 100,000 times in one day and about 35 million times in a year. During an average lifetime, the human heart will beat more than 2.5 billion times.
Give a tennis ball a good, hard squeeze. You're using about the same amount of force your heart uses to pump blood out to the body. Even at rest, the muscles of the heart work hard--twice as hard as the leg muscles of a person sprinting.
Feel your pulse by placing two fingers at pulse points on your neck or wrists. The pulse you feel is blood stopping and starting as it moves through your arteries. As a kid, your resting pulse might range from 90 to 120 beats per minute. As an adult, your pulse rate slows to an average of 72 beats per minute.
The aorta, the largest artery in the body, is almost the diameter of a garden hose. Capillaries, on the other hand, are so small that it takes ten of them to equal the thickness of a human hair.
Your body has about 5.6 liters (6 quarts) of blood. This 5.6 liters of blood circulates through the body three times every minute. In one day, the blood travels a total of 19,000 km (12,000 miles)--that's four times the distance across the US from coast to coast.
The heart pumps about 1 million barrels of blood during an average lifetime--that's enough to fill more than 3 super tankers.
lub-DUB, lub-DUB, lub-DUB. Sound familiar? If you listen to your heart beat, you'll hear two sounds. These "lub" and "DUB" sounds are made by the heart valves as they open and close.
Amazing Facts

3. Walls of the Heart
Heart is a hollow organ enclosed in a fluid-filled, double-walled sac
Pericardium
The outer wall anchors the heart to the sternum, diaphragm, and the lungs.
2 inner walls separated by a fluid that allows the heart to beat in a frictionless environment.

4. Heart Layers Epicardium Outer layer Myocardium Heart muscle. The
workhorse of the heart. Strong enough to pump blood through 60,000 miles of vessels and back to the heart.
Endocardium
Inner layer. Layer of the chambers and valves. Helps blood flow smoothly.

5. The Four Chambers of the Heart
The heart has an atrium and ventricle on both sides.
Atria are the collecting chambers,
Ventricles are the pumping chambers
Atria separated by interatrial septum
Ventricles by interventricular septum
Purpose of septum = avoiding mixing oxygenated and deoxygenated blood

7. The Heart
The heart is divided into left and right halves and has four chambers.
Two atria and two ventricles
The atria are the first chambers to receive blood from the body.
They fill with blood, contract, and transfer blood to the pumping chambers – ventricles
The r. ventricle pumps deoxygenated blood to the lungs and the l. ventricle pumps oxygenated blood to the rest of the body.
To prevent this from happening the other way, the heart has build in doors or valves that open only to a certain direction. Between the r. atrium and the r. ventricle we have the (4) ticuspid valve. (has three flaps) The one between the l. atrium and the l. ventricle has only two flaps and is therefore called (12) bicuspid valve. The we have to more valves to prevent backflow of blood into the ventricles: On the right side is the (6) pulmonary semilunar valve and on the left side is the (14) aortic semilunar valve.

8. 4 Heart Valves
Allow blood to flow only in one direction = Atrio-ventricular
Located between the atrium and ventricle
When these valves are open, they allow blood to flow from the atria into the ventricles.
Tricuspid Valve (right side)
Named because it has three flaps.
Bicuspid (mitral) (left side)
Named because it has two flaps

9. 4 Heart Valves Semilunar Valves
Allow blood to flow from the ventricles to the lungs and the rest of the body.
Pulmonary valve
Aortic valve
Have 3 half-moon flaps

10. Cardiac Cycle Consists of two phases: contraction and relaxation
systole (contraction)
diastole (relaxation)
Chambers are filling with blood
Referred to what happens in the ventricles, since they are the ones that pump the blood.
Chambers are pumping blood out of the heart

11. Cardiac Cycle
During the cycle the AV valves and the semilunar valves make a sound when they close:
“lub-dub”
lub = when the tricuspid and mitral close
dub = when the pulmonary and aortic close

12. Cardiac Cycle Time: Calculating mean arterial pressure (MAP)
One cycle is approximately 0.81 seconds in duration
2/3 of the 0.81 sec (0.54 sec) in diastole while 0.27 sec. is spent in systole.
Calculating mean arterial pressure (MAP)
MAP = 2/3 of diastolic x 1/3 of systolic blood pressure blood pressure

13. MAP determines the mean arterial pressure, which determines blood flow through the organs. If this pressure falls below 60 mmHG (millimeters or mercury) the organs will become damaged from lack of oxygen.

14. Cardiac Output
The amount of blood pumped from the heart per minute is called cardiac output (L/min).
Stroke volume (SV) is the amount of blood pumped from the heart per beat (mL/beat)
Average heart rate (HR) is 72 beats/min and 70 mL/beat = 5,040 ml in men
How to calculate cardiac volume:
SV x HR = Q (cardiac output)
(mL/beat) (beats/min)

15. Blood Circulation
Blood flows through the pulmonary circuit – all blood vessels that take deoxygenated blood from the right ventricle to the lungs and then return oxygenated blood to the left atrium.
The part where the oxygenated blood flows to the body is called the systemic circuit.
VAHA page 149

16. B1 Superior/Inferior Vena Cava
B4 Aortic Arch
B5 Aorta
B9 Pulmonary Trunk
B10 Pulmonary arteries
B11 Pulmonary veins
B12/13 Coronary arteries (r/l)
C1 r. atrium
C2 l. atrium
C3 r. ventricle
C4 l. ventricle

18. Blood Flow Through the Heart
_________________blood enters the __________(inferior and superior vena cava) Blood collects in _____________
Pressure increases against the tricuspid valve = __________

19. Blood Flow Through the Heart
_________________contracts and causes the pressure to increase in the chamber.
________ valve closes
____________ valve opens
Blood forced into _________________.

20. Blood Flow Through the Heart
Pulmonary artery carries the blood to_____________, where it becomes ____________ in the capillary network of the lungs.
Oxygenated blood returns to the left atrium via the pulmonary veins.

21. Blood Flow Through the Heart
Blood collects in the left atrium, causing pressure to increase in the chamber, forcing the mitral valve to open.
Left ventricle is filling with blood
Left ventricle contracts, pressure increases = mitral valve

22. Blood Flow Through the Heart
Left ventricle contracts, pressure increases = mitral valve closes and aortic valve opens. Blood is forced into the aorta.
____________ blood begins its journey of supplying ________ to all parts of the _____________.

23. Electrocardiography
The making and study of graphic records produced by electrical currents originating in the heart.
Electrocardiogram: A record of the electrical activity of the heart – shows waves called P, Q, R, S, and T.
P wave is caused by contraction of the atrium muscle, Q, R, S, and T waves are caused by ventricle muscle contraction
The electrocardiogram gives important information concerning the spread of excitation to the different chambers of the heart and it is of value in the diagnosis of cases of abnormal cardiac rhythm and damage.

24. The P to Q interval lasts for approximately 0
The P to Q interval lasts for approximately 0.16 seconds and is caused by blood flowing into the left and right atria.
The Q wave is the opening of the valve in the left atrium and the R wave is caused by the contraction of the ventricle. The QRS lasts for approximately 0.08 seconds. No blood flow
The S-T segment is the phase when blood is pushed through the ventricles, while the T wave is the decontraction of the ventricle.

25. Cardiac Arrhythmias bradycardia tachycardia
slow heart beat
tachycardia
fast heart beat
premature atrial contraction (PACs)
atria contracts before SA node

26. Cardiac Arrhythmias atrial fibrillation
atria contract faster than 350 bpm
premature ventricular contractions (PVCs)
ventricles contract too soon
ventricular tachycardia (VT)
ventricles, rather than SA node, cause beat

27. Cardiac Arrhythmias ventricular fibrillation (VF) heart block
ventricles contract faster than 350 bpm
heart block
impulse from SA node to AV node
first–impulse delayed
second–intermittently blocked
third–completely blocked

28. Defibrillators and Life-Threatening Arrhythmias
automatic external defibrillator (AED)
electric shock
stops heart
allows heart to start normal rhythm
anyone can use one

29. Heart Sounds
Systole – contraction
Diastole - relaxation

30. Heart Sounds Murmur: soft blowing or rasping sound
caused by the valve not closing properly.
can be born with or appear in sickness

31. Heart Sounds Atrial Septal Defect
The septum is the wall that separates the heart’s left and right sides.
Septal defects are called a “hole” in the heart mixing O2 with CO2
The problem is that oxygen rich blood flows back to the lungs and causes the heart to work overtime for the amount of O2 that reaches the body.

32. Heart Sounds Pulmonary stenosis stenosis means narrowing
Pulmonary stenoisis is the narrowing of the pulmonary valve
This causes decrease of blood flow and eventually enlarges the right atrium.

33. Heart Sounds Ebstein’s Anomaly
is a heart defect in which the tricuspid valve is abnormally formed. Two of its three leaflets are stick to the heart wall, and most always the heart has an atrial septal defect.
With this defect – with every heartbeat some blood gets pumped backwards which could cause heart failure.

34. The Cardiovascular System: Blood Vessels
Chapter Twenty-One

35. VAHA 151 5 Types of Blood vessels
Arteries - away
Arterioles small artery leads into capillaries
Capillaries where veins and arteries unite
Venules small vein, leads into capillaries
Veins – towards (have valves)
Arteries always carry blood away from the heart. They are thicker-walled than veins because the blood within them is at a higher pressure.
All veins always carry blood back to the heart. Because the pressure within them is lower, they are thinner-walled. Larger veins contain valves at regular intervals to assist the blood to return to the heart. Arteries and veins connect together at the microscopic level by capillary networks.
Capillaries are the smallest blood vessels in the body and are very important functionally because gas and fluid exchange occurs here. Their entire wall is often a single cell layer in thickness.
Don’t confuse yourself by trying to distinguish between arteries and veins as to whether they carry oxygenated blood or not. Some arteries/veins do and others don’t. - pulmonary artery
Roundtrip of blood from right atrium back the the right atrium is about a minute

36. Blood Vessels: The Transport Network

37. 3 Layers of Blood Vessesl
tunica intima
innermost layer
tunica media
middle layer
tunica externa
outermost laye

39. Capillaries exchange vessels capillary bed precapillary sphincters
gas moves between tissue and blood
capillary bed
network of exchange vessels
precapillary sphincters
close off capillary bed as needed

40. Circulation cardiopulmonary circulation systemic circulation
between heart and lungs
systemic circulation
between heart and body

43. Blood Pressure Blood pressure is the force in the arteries when
the heart beats (systolic
pressure) and when the
heart is at rest (diastolic pressure). It's measured in millimeters of mercury (mm Hg). High blood pressure (or hypertension) is defined in an adult as a blood pressure greater than or equal to 140 mm Hg systolic pressure or greater than or equal to 90 mm Hg diastolic pressure.
What is Blood Pressure? Blood is carried from the heart to all parts of your body in vessels called arteries. Blood pressure is the force of the blood pushing against the walls of the arteries. Each time the heart beats (about times a minute at rest), it pumps out blood into the arteries. Your blood pressure is at its highest when the heart beats, pumping the blood. This is called systolic pressure. When the heart is at rest, between beats, your blood pressure falls. This is the diastolic pressure. Blood pressure is always given as these two numbers, the systolic and diastolic pressures. Both are important. Usually they are written one above or before the other, such as 120/80 mmHg. The top number is the systolic and the bottom the diastolic. When the two measurements are written down, the systolic pressure is the first or top number, and the diastolic pressure is the second or bottom number (for example, 120/80). If your blood pressure is 120/80, you say that it is "120 over 80." Blood pressure changes during the day. It is lowest as you sleep and rises when you get up. It also can rise when you are excited, nervous, or active.

44. Still, for most of your waking hours, your blood pressure stays pretty much the same when you are sitting or standing still. That level should be lower than 120/80. When the level stays high, 140/90 or higher, you have high blood pressure. With high blood pressure, the heart works harder, your arteries take a beating, and your chances of a stroke, heart attack, and kidney problems are greater.
What causes it? In many people with high blood pressure, a single specific cause is not known. This is called essential or primary high blood pressure. Research is continuing to find causes. In some people, high blood pressure is the result of another medical problem or medication. When the cause is known, this is called secondary high blood pressure

45. What is high blood pressure
What is high blood pressure? A blood pressure of 140/90 or higher is considered high blood pressure. Both numbers are important. If one or both numbers are usually high, you have high blood pressure. If you are being treated for high blood pressure, you still have high blood pressure even if you have repeated readings in the normal range. There are two levels of high blood pressure: Stage 1 and Stage 2 (see the chart below). Categories for Blood Pressure Levels in Adults* (In mmHg, millimeters of mercury) CategorySystolic (Top number)Diastolic (Bottom number)Normal
Less than 120
Less than 80
Prehypertension
80-89
High Blood PressureSystolicDiastolicStage 1
90-99
Stage 2
160 or higher
100 or higher
* For adults 18 and older who:
Are not on medicine for high blood pressure
Are not having a short-term serious illness
Do not have other conditions such as diabetes and kidney disease

46. Causes of High Blood Pressure
The “Pill” can increase blood pressure
Osteoporosis – Ca- increase (stored in bones)

47. Symptoms of High Blood Pressure
Usually, there are no specific symptoms which indicate that someone has high blood pressure. But some population surveys have shown that a wide variety of common symptoms, such as sleep disturbance, emotional upsets, and dry mouth, are slightly commoner in people with higher pressures. The differences are small, however. Going red in the face, or feeling flushed, is not indicative of high blood pressure.

48. How to lower Blood Pressure
Lose weight
Quite smoking
Exercise
Reduce Stress
Decrease Alcohol

49. How it’s checked around the upper arm. A hand bulb pumps air into
1.A soft arm cuff is wrapped
around the upper arm.
A hand bulb pumps air into
the cuff, gently squeezing
the arm and temporarily interrupting the flow of blood. The pressure gauge reaches a peak.
2.Then the cuff is slowly deflated, letting blood flow again. As the cuff deflates and the pressure gauge gradually decreases, the return of the blood flow through the main artery in your arm can be heard using a stethoscope.
3. The reading on the pressure gauge when the pulse is first heard is your systolic pressure (the peak pressure as the heart contracts).
The reading when the pulse can first no longer be heard is your diastolic pressure (the lowest pressure as the heart relaxes between beats).
Be seated, with your arms bared, supported and at heart level. Do not smoke or drink caffeinated beverages 30 minutes before testing. Sit quietly for five minutes before starting measurement. Make sure the measurement cuff fits comfortably around your arm. Take two or more readings, at least two minutes apart, and average results. Make sure your measurement cuff has been checked for accuracy.
How it’s checked

51. Low Blood Pressure
In many countries low blood pressure is regarded as a sign of excellent health, and it is certainly true that it is associated with a good outlook from the point of view of risks of strokes an heart attacks
low blood pressure may be associated with fatigue, weakness, and depression. There may be overlap with the “chronic fatigue syndrome”, which remains poorly defined, and we do not know if it is the low pressure that is actually responsible for any of these symptoms.

52. Why Hypertension Matters
A growing fetus gets everything from mom--all the nutrients and oxygen necessary to grow normally. Since the mother's blood supplies the oxygen, it's important that the right amount of blood and nutrients travel to the fetus through the placenta and the umbilical cord.
High blood pressure can affect the amount of blood and nutrients the fetus receives. Sometimes the growth and development of the fetus can be slowed
Preeclampsia

53. Between 40 and 90 percent
of all stroke patients had high
blood pressure before their
stroke. Hypertension puts
stress on blood vessel walls.
This can lead to stroke from
clots or bleeding.
Ischemic stroke An ischemic stroke occurs when an artery supplying the brain with blood becomes blocked, suddenly decreasing or stopping blood flow to the brain. Eighty percent of all strokes fall into this category. The blockage is often caused by fatty deposits in the blood vessel walls. If you have these fatty deposits, which include cholesterol
Hemorrhagic stroke These strokes account for the remaining 20 percent of strokes. When an artery in the brain bursts, blood flows into surrounding tissue and neurons in the brain are upset. High blood pressure combined with cholesterol can contribute to hemorrhage. An artery encrusted with plaque from cholesterol becomes brittle and prone to cracks. Hypertension increases the risk that a brittle wall will give way and release blood into surrounding tissue.
Stroke
A stroke is a kind of brain injury that occurs when the blood supply to part of the brain is suddenly interrupted or a vessel bursts.

54. Heart Failure
Heart failure occurs when the heart can't pump enough blood to meet the needs of the body. The condition usually develops slowly over years, as the heart gradually loses its pumping ability and works less efficiently. Some people may not become aware of their condition until symptoms appear years after the heart begins its decline.
smoking, high cholesterol levels, persistent high blood pressure, diabetic abnormal blood sugar levels (diabetes) and obesity. A single risk factor may be sufficient to cause heart failure, but a combination of factors dramatically increases the risk. Of course also genetic heart defects or heart defects people are born with.

55. Organs, Abdominal Cavity and lower lips