Ch 18 Cardiovascular System The Heart

Front 1

Where is the heart located?

Back 1

The heart is located approximately five fingers below the left nipple in the mediastinum of the thorax.

Front 2

The heart is made up of two layers, the outer and the inner. Describe what the outer layer is made of.

Back 2

The outer layer is made of connective tissue, and is called the fibrous pericardium.

Front 3

The heart is made up of two layers, the outer and the inner. Describe what the inner layer is made of.

Back 3

The inner layer of the heart is made of epithelial tissue, is called the serous membrane, and is made of three parts. The outermost layer is called the parietal pericardium, the innermost layer is called the visceral pericardium (also known as the epicardium), and between the parietal and visceral layer is filled with pericardial fluid, and is called the pericardial cavity.

Front 4

What is a serous membrane?

Back 4

Serous membranes line internal body cavities.

Front 5

What is a mucous membrane?

Back 5

Mucous membranes line passageways open to the outside world.

Front 6

In terms of physiology, what does visceral mean?

Back 6

Visceral means organs, or guts.

Front 7

Describe pericarditis.

Back 7

Pericarditis is an inflammation of the pericardium, which is often caused by an infection or a heart attack. IV drug users often get this infection.

Front 8

Describe cardiac tamponade.

Back 8

Cardiac tamponade is a condition where there is a buildup of fluid in the pericardium. IV drug users often get this infection.

Front 9

What is a membrane composed of?

Back 9

A membrane is composed of an epithelium bound to an underlying layer of connective tissue.

Front 10

Name and describe the location of the three layers of the heart wall.

Back 10

The epicardium is the outer most layer, the myocardium (composed of specialized cardiac muscle cells) is the middle layer and the innermost layer is the endocardium.

Front 11

What is the cutaneous layer composed of?

Back 11

The cutaneous layer is another name for skin.

Front 12

What does atrium mean?

Back 12

Atrium means courtyard.

Front 13

What are auricles, and how many are there?

Back 13

Auricles are small wrinkled protruding appendages that slightly increase the heart volume. There is a left and a right auricle.

Front 14

What are pectinate muscles, and where are they found?

Back 14

Pectinate muscles are ridged muscles that look like the teeth of a comb that are found in the left and right atria.

Front 15

What does pectin mean?

Back 15

Pectin means comb.

Front 16

16. What are the atria, how many are there, and what are their purposes?

Back 16

These are the receiving chambers of the heart. The right atrium receives de-oxygenated blood from the inferior and superior vena cava, and the left atrium receives oxygenated blood from the right and left pulmonary veins. The right atria also receives blood from the coronary sinus.

Front 17

17. What is the fossa ovalis?

Back 17

The fossa ovalis is depression that marks the spot where the foramen ovale was in the fetal heart.

Front 18

18. What is the foramen ovale?

Back 18

The foramen ovale is the hole that connects the atria in the fetal heart that is used because the blood being used by the fetus is already oxygenated.

Front 19

19. What kind of complication can arise if the foramen ovale doesn’t completely close?

Back 19

If the foramen ovale doesn’t completely close the person may experience migraine headaches, and strokes.

Front 20

20. What are the ventricles, how many are there, and what are their purposes?

Back 20

The ventricles are the discharging chambers of the heart. The right ventricle pumps de-oxygenated blood into the pulmonary circulation system, and the left ventricle pumps oxygenated blood into the system systemic circulation system.

Front 21

What is the systemic circulation system?

Back 21

The systemic circulation system brings oxygenated blood to the body, and brings back de-oxygenated blood to the heart.

Front 22

What is the pulmonary system?

Back 22

The pulmonary system brings de-oxygenated blood from the heart to the lungs, and brings oxygenated blood to the lungs to the heart.

Front 23

What are trabeculae carneae?

Back 23

Trabeculae carneae are fleshy beams of muscle that line the inner surface of the ventricles.

Front 24

What does trabeculae mean?

Back 24

Trabeculae is small beam, strut, or rod that generally serves a mechanical function, and is made of collagenous tissue.

Front 25

What does carneae mean?

Back 25

Carneae means flesh.

Front 26

What are papillary muscles?

Back 26

Papillary muscles serve by limiting the movement of the tricuspid and bicuspid valves. When they contract they tighten the chordae tendineae, and insure there won’t be any blood regurgitated back into the atria.

Front 27

Describe the pathway of blood through the heart.

Back 27

a. De-oxygenated blood is brought into the right atria from the inferior and superior vena cava
b. Blood is then routed through the tricuspid valve and into the right ventricle.
c. Through the pulmonary semi-lunar valve and through the pulmonary artery.
d. Gets oxygenated in the lungs
e. Oxygenated blood is then enters the left atria from the right and left pulmonary veins.
f. Through the bicuspid valve and into the left ventricle
g. Out through the aortic semi-lunar valve and through the aorta

Front 28

Describe coronary circulation.

Back 28

Two coronary arteries branch from the aorta as it leaves the heart and blood returns from the heart walls to the right atrium via the coronary sinus.

Front 29

Describe angina pectoris, and list the four E’s of angina.

Back 29

Angina pectoris, which is commonly known as angina, is chest pain caused by ischemia of the heart, and is generally caused by obstruction to the coronary arteries. The four E’s of angina are: eating, exercise, emotional stress, and exposure to cold, all of which increase the hearts workload.

Front 30

What is ischemia?

Back 30

Ischemia is a lack of blood, and hence oxygen supply.

Front 31

31. What is myocardial infarction (MI)?

Back 31

Myocardial infarction is also known as a heart attack, is when the blood supply to part of the heart is interrupted.

Front 32

32. What kind of myocardial infarction is most serious?

Back 32

Blood clots in the left coronary artery are often fatal if not treated quickly. Less severe MI’s result from blockages of the circumflex artery or the right coronary artery.

Front 33

33. What are three anti-clot drugs, when should they be taken, and what is a common complication of administering these drugs.

Back 33

TPA (tissue plasminogen activator), streptokinase, and Retavase work by breaking down blood clots. TPA should be given within six hours of a heart attack or stroke. The incorrect dosage of TPA kills about 1500 people yearly.

Front 34

34. What are signs of a heart attack?

Back 34

Chest pains are a sign, but many women don’t experience chest pains before a heart attack. Unusual fatigue and sleepiness up to a month in advance might be an indicator for women.

Front 35

35. What is C-reactive protein?

Back 35

C-reactive protein is an inflammatory protein that appears to damage the lining of artery walls and contribute to formation and rupture of plaques, and may be as important as lowering of cholesterol.

Front 36

Describe what a blood clot is, and give another name for one.

Back 36

A blood clot is the final step in blood coagulation, and is also called a thrombus.

Front 37

What is cardiac arrest?

Back 37

Cardiac arrest is the abrupt cessation of circulation of blood caused by the ventricles not contracting properly. Cardiac arrest is not the same as a myocardial infarction.

Front 38

Within how long should the heart be given a shock once it stops, and what is the name of the equipment that administers the shock?

Back 38

The heart should be given a shock within 2 minutes of it stopping, and this is done with a defibrillator.

Front 39

What is code blue?

Back 39

A code blue is an adult medical emergency.

Front 40

What is an atrioventricular valve, and what sound does it make?

Back 40

The atrioventricular valves control the blood coming into the ventricles from the atria, and they make the ‘lub’ sound. The right AV valve is called the tricuspid valve, and the left AV valve is called the bicuspid or mitral valve.

Front 41

What is an occlusion?

Back 41

An occlusion is a term used to describe a blockage in a blood vessel that prevents any blood flow.

Front 42

What is semi-lunar valve, name the two of the heart, and what sound do they make?

Back 42

A semi-lunar valve controls the flow of blood from the ventricles and outside the heart.
The aortic semi-lunar valve controls blood from the left ventricle and the aorta, and the pulmonary semi-lunar valve controls blood from the right ventricle and the pulmonary artery. The semi-lunar valves make the ‘dub’ sound.

Front 43

What do you call a blood clot caused from sitting inactive too long?

Back 43

A blood clot from sitting inactive too long is called deep venous thrombosis.

Front 44

Describe the microscopic anatomy cardiac muscle fibers in comparison with skeletal muscle.

Back 44

a. The similarities that cardiac muscle fibers have with skeletal muscle are: striations, actin & myosin, sacromeres, and sliding filament mechanism.
b. The differences are cardiac muscles are: branched cells, contract w/o nervous stimulation, and are intercalated discs.

Front 45

What is a functional syncytium?

Back 45

The intercalated discs contain anchoring desmosomes and gap junctions. The desmosomes prevent neighboring cells from separating during contraction, and the gap junctions allow ions to pass from cell to cell, transmitting current across the entire heart.

Front 46

46. What are sacromeres?

Back 46

A sacromere is the smallest contractible unit of muscle that connects one ‘z’ disc to the next.

Front 47

47. What are actin and myosin?

Back 47

Actin and myosin are contractile proteins of muscle.

Front 48

48. What are desmosomes?

Back 48

A desmosome is a cell structure specialized for cell-to-cell adhesion.

Front 49

49. What are intercalated discs?

Back 49

The plasma membranes of neighboring cardiac cells interlock at dark-staining junctions called intercalated discs that contain gap junctions and desmosomes.

Front 50

50. What is autorhythmicity?

Back 50

51. Some cardiac muscle cells are self-excitable and can initiate their own depolarization, and that of the rest of the heart, in a spontaneous and rhythmic way. This is called autorhymicity.

Front 51

What are the two structural features that underlie the heart’s ability to be excited?

Back 51

The two structural features that allow the heart to be excited are gap junctions, and the conduction system.

Front 52

What are gap junctions?

Back 52

A gap junction is a junction between certain animal cell-types that allows different molecules and ions to pass freely between cells. The junction connects the cytoplasm of cells.

Front 53

What is the intrinsic conduction system?

Back 53

The intrinsic conduction system doesn’t need outside nerve signal to fire.

Front 54

What is the difference between organ and motor unit contraction?

Back 54

In skeletal muscle, all cells of given motor unit are stimulated and contract at the same time. Impulses don’t spread from cell to cell. In cardiac muscle, the heart either contracts as a unit or doesn’t contract at all. This is due to the transmission of the depolarization wave across the heart from cell to cell via ion passage through gap junctions.

Front 55

What is the absolute refractory period, what is happening to sodium channels, and approximately how long is it for the heart?

Back 55

A refractory period is the inexcitable period when sodium channels are still open or inactivated. This lasts approx 250 ms in cardiac muscle cells, nearly as long as the contraction. (Muscle cells 1-2 ms for contractions that last 15-100ms)

Front 56

What are the energy requirements of the heart?

Back 56

The heart requires oxygen to function. It also needs either, glucose, fatty acids, and or lactic acids.

Front 57

Describe the action potential process in the heart with respect to the autorhythmic cells and pacemaker potentials, also, what’s another name for pacemaker pre potentials?

Back 57

The autorhythmic cells that are part of the intrinsic conduction system don’t keep a stable resting membrane potential. They have an unstable resting potential that continuously depolarizes. These spontaneously changing membrane potentials are called pacemaker potentials or prepotentials, and they start the action potentials that spread through the heart and trigger its rhythmic contractions.

Front 58

Describe the sequence of excitation.

Back 58

a. From the SA node the depolarization wave spreads via gap junctions throughout the atria and to the AV node. At the AV node the impulse is delayed for about .1 s, which allows the atria to respond and complete their contraction before the ventricles contract.
b. From the AV node to the impulse travels to the atrioventricular bundle (AV bundle), although the atria and ventricles abut each other, they aren’t connected by gap junctions, only by the AV bundle
c. The AV bundle then splits into the right and left bundle branches, which go along the interventricular septum toward the heart apex.
d. The Purkinje fibers go the rest of the way through the interventricular septum into the heart apex, and turn superiorly into the ventricular walls.
e. Ventricular contraction almost immediately follows ventricular depolarization wave.

Front 59

Where is the sinoatrial node located, and if left alone, what would it keep the heart rate at, and what is it also known as?

Back 59

The sinoatrial node is also known as the SA node, if left alone it would keep the heart rate at 100 x minute. The SA node is located in the wall of the right atrium, just inferior to the entrance of the superior vena cava.

Front 60

Where is the atrioventricular node located, and if left alone, what would it keep the heart rate at?

Back 60

The atrioventricular node is also known as the AV node, if left alone it would keep the heart rate at 50 x minute, and it’s located in the inferior portion of the interatrial septum, just above the tricuspid valve.

Front 61

62. Where is the AV bundle located, what is another name for this, and if left alone, what would it keep the heart rate at?

Back 61

The AV bundle is located in the superior part of the interventricular septum, it is also known as the bundle of His, and if left alone, it would keep the heart rate at 35 x minute.

Front 62

Where are the right and left bundle branches located?

Back 62

The left and right bundle branches

Front 63

Where are the purkinje fibers located, and what heart rate, if left alone, would the Purkinje fibers keep the heart at?

Back 63

The Purkinje fibers are located in the complete the path through the interventricular septum, into the heart apex, and then superiorly into the ventricular walls. If left alone, the Purkinje fibers would keep the heart at about 30 x minute.

Front 64

What is arrhythmia?

Back 64

Defects in the intrinsic conduction system may cause arrhythmias, which are irregular heart rhythms.

Front 65

What is fibrillation, and what is a heart in fibrillation compared to?

Back 65

Fibrillation is a condition of rapid and out-of-phase contractions in which control of heart rhythm is taken away from the SA node by rapid activity in other regions. A heart in fibrillation is compared to a squirming bag of worms.

Front 66

What happens if defibrillation doesn’t happen quickly?

Back 66

Because fibrillating ventricles don’t work as pumps, unless the heart is defibrillated quickly, blood flow will cease, and brain death will occur.

Front 67

What is the ectopic focus, and what is it also known as?

Back 67

This can also be thought as another pacemaker taking over for a defective SA node. Sometimes this happens even when the SA node is firing, and can in that instance is a result of hyperexciteability of a certain region due to too much caffeine or nicotine.

Front 68

How does a defibrillator work?

Back 68

A defibrillator works by sending an electric charge to the heart, which depolarizes the whole heart, and hopefully resetting the SA node.

Front 69

What is bradycardia?

Back 69

Bradycardia is a heart rate under 60beats/minute.

Front 70

What is tachycardia, and how can this be easily remembered?

Back 70

Tachycardia is a heart rate of over 120beats/minute, this can be remembered when thinking about the tachometer on a car.

Front 71

What is the parasympathetic nerve system?

Back 71

The parasympathetic nervous system acts as the “brake” of the autonomic nervous system.

Front 72

73. What is the sympathetic nerve system?

Back 72

The sympathetic nervous system acts as the “accelerator” of the autonomic nervous system.

Front 73

74. What is the autonomic nerve system?

Back 73

The autonomic nervous system is part of the peripheral nervous system.

Front 74

75. What is the enteric division of the nervous system.

Back 74

The enteric division is part of the autonomic nervous system and it controls the bowels.

Front 75

76. Describe what extrinsic innervations of the heart is, and name what controls this.

Back 75

The heart is sped up by the sympathetic (accelerator) system and slowed by the parasympathetic system (brake). The cardiac centers that can override this control are in the medulla.

Front 76

77. What is an electrocardiograph?

Back 76

An electrocardiograph is a machine that reads the electrical currents generated in the heart and throughout the body.

Front 77

78. What is an electrocardiogram?

Back 77

An electrocardiogram is a graphic record of the electrical activities of the heart.

Front 78

79. Name the three distinguishable waves/deflections, and describe what is happening with the heart at each interval.

Back 78

a. The first small wave is the ‘P’ wave, this is caused by atrial depolarization
b. Between the ‘P’ and ‘Q’ wave the atria depolarize and contract
c. The ‘R’ wave is ventricular depolarization
d. The QRS complex is from ventricular depolarization, and is before ventricular contraction.
e. The T wave is caused by ventricular repolarization.

Front 79

80. What is happening when the heart makes the ‘lub’ ‘dub’ sound?

Back 79

The ‘lub’ is the sound of the AV valves closing, and the ‘dub’ is the sound of the semi-lunar valves closing.

Front 80

81. What are murmurs and bruits?

Back 80

A heart murmur is a turbulent blood flow that is sufficient to make noise. A bruit indicates a fatty build up in a vessel, and is heard as an abnormal sound.

Front 81

82. What is atherosclerosis?

Back 81

Atherosclerosis is a disease affecting arterial blood vessels. It is a chronic inflammatory response in the walls of arteries, in large part due to the deposition of lipoproteins (plasma proteins that carry cholesterol and triglycerides). It is commonly referred to as a "hardening" or "furring" of the arteries. It is caused by the formation of multiple plaques within the arteries.

Front 82

83. What is stenosis?

Back 82

A stenosis is an abnormal narrowing of a blood vessel or tubular organ, or structure.

Front 83

84. Describe the cardiac cycle, listing the names of specific points in the cycle.

Back 83

a. The cycle starts in mid-to-late diastole when the pressure in the heart is slow, and blood returning from circulation is flowing passively through the atria and the open AV valves into the ventricles (approximately 70% of ventricle filling is passive, and the remaining 30% is active), and the SL valves are closed.
b. Following the P wave of the ECG, the atria contract, compressing the blood in their chambers, which causes a sudden slight rise in atrial pressure, and pushes residual blood out of the atria into the ventricles.
c. The ventricles are in their last part of diastole and have the maximum blood volume they can have, which is called the end diastolic volume (EDV)
d. The atria relax and the ventricles depolarize (QRS complex), atrial diastole persists through the rest of the cycle
e. As the atria relax the ventricles begin contracting, and the AV valves close.
f. For a split second the ventricles are completely closed chambers and blood volume in the chambers remains the same, this is called the isovolumetric contraction phase
g. The pressure in the ventricles continues to rise until it exceeds the pressure in the large arteries and the SL valves are opened (this is the end of the isovolumetric contraction phase)
h. During the brief phase following the T wave, the ventricles relax.
i. The blood remaining in their chambers after contraction is called the end systolic volume (ESV)
j. Ventricular pressure drops and blood backflows toward the heart from the pulmonary arteries and the aorta, closing the SL valves.

Front 84

85. How long is one heartbeat, and how long are its parts?

Back 84

A heart beat takes place in about .8s. Atrial systole takes about .1s, ventricular systole takes about .3s, and diastole takes about .4s.

Front 85

86. What is cardiac output, what is the formula for cardiac output, and what is cardiac output also known as?

Back 85

Cardiac output is the amount of blood pumped out of EACH ventricle in 1 minute. Cardiac output (CO): CO = HR(heart rate) x SV(stroke volume).

Front 86

87. What is the average adult cardiac output?

Back 86

Normal CO is 5250 ml/min = 75beats/min x 70ml

Front 87

What is stroke volume, and what is the formula for stroke volume?

Back 87

Stroke volume is the volume of blood pumped out by one ventricle with each beat. Stroke volume is expressed as: SV = EDV – ESV

Front 88

What is normal end diastolic volume?

Back 88

A normal end diastolic volume is 120ml.

Front 89

What causes the cardiac output to increase, and what causes it to decrease?

Back 89

Cardiac output is increased when either the stroke volume or the heart rate is increased, or both, and it decreases when either one lessens, or if both of them lessen.

Front 90

How is the average adult blood volume, and how long does this blood typically take to get through each side of the heart?

Back 90

The average adult blood volume is about 5 liters and takes about one minute for each side of the heart to cycle through it.

Front 91

What are the two factors that affect EDV?

Back 91

End diastolic volume is affected by the length of ventricular diastole, and by venous pressure, which is how much blood is coming back on the right side.

Front 92

What are the two factors that affect ESV?

Back 92

End systolic volume is affected by arterial blood pressure, and the force of ventricular contraction.

Front 93

What is preload, and what can it affect?

Back 93

Preload is the amount of blood in the ventricles before contraction, and it affects SV.

Front 94

State the Frank-Starling law of the heart.

Back 94

The Frank-Starling law of the heart states that the more the ventricle is filled with blood during diastole (end-diastolic volume), the greater the volume of ejected blood will be during the resulting systolic contraction (stroke volume).

Front 95

How does the Frank-Starling law of the heart relate to venous return, and does venous return affect SV?

Back 95

Venous return is the rate of blood flow back to the heart. Therefore the more blood filling the heart during diastole (EDV), the greater the volume of blood ejected (SV) will be. Venous return affects SV.

Front 96

What are three things that can affect contractility, and what can contractility affect?

Back 96

E, NE, Ca++, and the drug digitalis can affect contractility. Contractility can affect SV.

Front 97

What is afterload, and what can it affect?

Back 97

Afterload is back pressure, like blood pressure, and it can affect strove volume.

Front 98

What is vagal tone?

Back 98

Vagal tone is when both the parasympathetic (brake) and sympathetic (accelerator) divisions of the autonomic nervous system are sending impulses to the SA node via the vagal nerves. The result is mostly inhibitory, and if cut there would be an instant increase of 25beats/minute, which reflects the inherent pacemaker rate of the SA node.

Front 99

What is the atrial reflex, and what is it also known as?

Back 99

The atrial bridge is also known as the Bainbridge reflex, and is a sympathetic reflex initiated by increased venous return and increased atrial filling.

Front 100

What are two hormones that regulate heart rate?

Back 100

Both epinephrine, which is released by the adrenal medulla by the sympathetic division, and thyroxine, which is produced by the thyroid gland, increase the heart rate.

Front 101

What are three ions that affect the heart rate?

Back 101

Three ions that affect the heart rate are calcium, sodium, and potassium.

Front 102

What is CHF?

Back 102

Congestive heart failure is not the same as cardiac arrest, where the heart stops, but is a condition that disallows the heart to pump an appropriate amount of blood through the body.

Front 103

What is the name of CHF on the left and on the right side?

Back 103

CHF on the left side is called pulmonary congestion, and CHF on the right side is called peripheral congestion.

Front 104

How does acetylcholine affect both the parasympathetic and sympathetic divisions?

Back 104

In the parasympathetic division acetylcholine slows the excitation of cardiac muscle fibers.
In the sympathetic division acetylcholine signals the medulla to release adrenaline, and noradrenaline (aka E or NE).