Cardiovascular system Flashcards
1
Q
What is the direction of blood flow in the systemic arteries?
A
From the left ventricle to the systemic circuit to provide blood to organs in the body
2
Q
What is the direction of blood flow in the systemic veins?
A
From the body organs to the right ventricle
3
Q
What is the direction of blood flow in the pulmonary arteries?
A
From the right ventricle to the lungs
4
Q
What is the direction of blood flow in the pulmonary veins?
A
From the lungs to the left ventricle
5
Q
Do systemic arteries carry oxygenated or deoxygenated blood?
A
Oxygenated blood
6
Q
Do systemic veins carry oxygenated or deoxygenated blood?
A
Deoxygenated blood
7
Q
Do pulmonary arteries carry oxygenated or deoxygenated blood?
A
Deoxygenated blood
8
Q
Do pulmonary veins carry oxygenated or deoxygenated blood?
A
Oxygenated blood
9
Q
What is the peak pressure in the left ventricle?
A
120mmHg
10
Q
What is the peak pressure in the right ventricle?
A
27mmHg
11
Q
What is the peak pressure in the left atrium?
A
8mmHg
12
Q
What is the peak pressure in the right atrium?
A
5mmHg
13
Q
What is the mean pressure in the right atrium?
A
3mmHg
14
Q
What is the mean pressure in the right ventricle?
A
20mmHg
15
Q
What is the mean pressure in the left atrium?
A
5mmHg
16
Q
What is the mean pressure in the left ventricle?
A
100mmHg
17
Q
What is the mean pressure in the systemic arteries?
A
90mmHg - 60mmHg
18
Q
What is the mean pressure in the systemic capillaries?
A
25mmHg
19
Q
What is the mean pressure in the pulmonary capillaries?
A
10mmHg
20
Q
What is the mean pressure in the pulmonary veins?
A
8mmHg
21
Q
What is the function of the superior and inferior venacava?
A
Flow of deoxygenated blood from the systemic veins into the right side of the heart
22
Q
What is the function of the left and right pulmonary arteries?
A
Flow of deoxygenated blood from the right side of the heart to the lungs
23
Q
What is the function of the left and right pulmonary veins?
A
Flow of oxygenated blood from the lungs to the left side of the heart
24
Q
What is the function of the aorta?
A
Flow of oxygenated blood from the left side of the heart to the systemic circuit
25
In the anterior/ventral view of the heart, what structures are visible?
Right ventricle, left ventricle, left atrium, superior and inferior venacavae, aorta, pulmonary trunk
26
In the posterior/dorsal view of the heart, what structures are visible?
Left atrium (small amount), left ventricle, right ventricle, right atrium, aorta, pulmonary arteries, pulmonary veins
27
Describe the inlet and outlet valves of the left ventricle?
Inlet valve - mitral (bicuspid) valve, outlet valve - aortic valve
28
Describe the inlet and outlet valves of the right ventricle?
Inlet valve - tricuspid valve, outlet valve - pulmonary valve
29
Describe the orientation of the heart?
Apex points anteriorly, inferiorly and slightly to the left. Two thirds of heart mass lies to the left of the midline. Right border formed by right atrium, inferior border formed by right ventricle, left border formed by left ventricle
30
Describe the pericardium?
A double layered "bag" that encloses the heart to prevent damage by friction
31
Moving from the outside in, list the structures forming the wall of the heart?
Outside pericardial space > fibrous pericardium > parietal pericardium > pericardial space > epicardium/ visceral pericardium > myocardium > endocardium > inside ventricle (blood)
32
What structures make up the pericardium?
Fibrous, parietal and visceral pericardium
33
What structures make up the heart wall?
Epicardium, myocardium, endocardium
34
Describe the conduction system of the heart?
SA node > AV node > AV bundle > bundle branches > purkinje fibres
35
Describe how the SA node works?
The SA node spontaneously depolarises, slow (0.5m/s) conducts electrical impulse to the AV node
36
Describe how the AV node works?
Very slow ( 0.05m/s) and causes a 100ms delay between atria firing and next step to allow ventricle to fill
37
Describe how the AV bundle works?
Fast (5m/s) conducts electrical impulse from AV bundle to bundle branches and then to purkinje fibres, allows even ventricular contraction
38
Describe the cardiac cycle?
```
1 - ventricular filling
2 - atrial contraction
3 - isovolumetric ventricular contraction
4 - ventricular ejections
5 - isovolumetric ventricular ejection
```
39
Describe ventricular filling?
Pressure in the ventricle is lower than that of the atrium, the mitral valve opens and blood flows from the atrium into the ventricle. Aortic valve is closed because pressure in the aorta is higher than in the ventricle.
40
Describe atrial contraction?
The atrium contracts to complete the filling of the ventricle
41
Describe isovolumetric ventricular contraction?
The ventricle begins to contract, blood moves back towards the atrium which closes the mitral valve (1st heart sound). The aortic valve is still closed. Pressure rises rapidly in the ventricle and volume remains the same
42
Describe ventricular ejection?
Pressure in the ventricle exceeds than of the aorta and the aortic valve opens to allow blood to flow into the aorta
43
Describe isovolumetric ventricular relaxation?
The ventricle relaxes, ventricular pressure drops and blood attempts to flow back into the ventricle which closes the aortic valve (2nd heart sound). mitral valve stays shut because ventricular pressure still exceeds atrial pressure. Ventricular pressure drops rapidly but volume remains the same.
44
Describe elastic arteries?
Very large arteries near the heart, have elastic walls which reduce pulsatile effect of blood ejecting from the ventricles
45
Describe muscular arteries?
Distribute blood around the body at high pressure, adjusts rate of blood flow using smooth muscle to constrict or dilate
46
Describe arterioles?
Control blood flow into capillary beds, greatest pressure drop occurs in arterioles and greatest resistance to flow, have thicker muscular wall in comparison to their size
47
Describe capillaries?
Small thin walled vessels which allow gas and nutrient exchange
48
Describe venules?
Low pressure, drain capillary beds, hold white blood cells
49
Describe veins?
Thin walled, low pressure, drain blood back to atria, reservoir to store blood
50
Describe coronary arteries?
Supply the muscles of the heart with blood
51
Describe mitral regurgitation?
Left ventricle dilates which causes the mitral valve fibrous rings to stretch meaning that the mitral valve can't close properly. When the ventricle contracts, blood flows back into the atrium. Therefore each time the ventricle has to pump more than the normal volume of blood to compensate for the leakage
52
What are some symptoms of mitral regurgitation?
Turbulence heard after the 1st heart sound using stethoscope, breathlessness
53
Why does mitral regurgitation cause breathlessness?
Left atrium pressure increases, which has a knock on effect of increasing pulmonary venous and capillary pressure, which results in more capillary leakage, making the lungs heavier and wetter and more rigid, and therefore breathing requires more muscular work and is more laboured resulting in breathlessness
54
Cardiac output = ?
Heart rate x stroke volume
55
Describe the different points in a pressure volume loop?
A - mitral valve opens, atrium contracts = low pressure, low volume
>> passive filling and atrial contraction = increase volume
B - mitral valve closes = low pressure, high volume
>> isovolumetric contraction = increase pressure
C - aortic valve opens = high pressure, no volume change
>> ejection of blood into aorta = decrease volume
D - aortic valve closes, isovolumetric relaxation = pressure drops, no volume change
56
Describe a typical electrocardiogram?
P wave - caused by depolarisation of atrial contractile fibres (SA node action potential)
QRS complex - caused by depolarisation of ventricular contractile fibres
T wave - caused by repolarisation of ventricular contractile fibres
57
Describe the steps involved in blood pressure regulation?
Decrease in blood pressure > detected by baroreceptors in carotid sinus and arch of aorta > stretch less which decreases rate of nerve impulses > detected by CV centre in medulla oblongata and adrenal medulla > increased sympathetic, decreased parasympathetic, increased secretion of epinephrine and norepinephrine from adrenal medulla > increased stroke volume and heart rate, increased cardiac output, constriction of blood vessels for increased vascular resistance and increased venous return > increased blood pressure > detected by baroreceptors continues feedback loop
58
What hormones are involved in blood pressure regulation?
Epinephrine - increases blood pressure by increasing heart rate and contractility
Norepinephrine - increases blood pressure by increasing heart rate and contractility
Angiotensin II - increases blood pressure by causing vasoconstriction which increases resistance
59
What do sympathetic nerves do to the heart?
```
Increase rate of spontaneous depolarisation in SA node which increases heart rate
Increased contractility (epinephrine and norepinephrine) causes increased stroke volume
```
60
What do parasympathetic (vagus) nerves do to the heart?
Decrease the rate of spontaneous depolarisation in the SA node which decreases heart rate
61
What side of the heart is the SA node found on?
The right side
62
When both the aortic and mitral valves are closed, what is happening with regards to pressure in the ventricle?
Both valves are shut during isovolumetric contraction and relaxation, so pressure is either rapidly increasing or decreasing
63
During the cardiac cycle, when do the papillary muscles contract?
When the tricuspid and mitral valves are closing
64
What type of valves have chordae tendinae?
Tricuspid and mitral valves
65
Why do the pulmonary and aortic valves lack chordae tendinae?
Because they open or close depending on blood filling their cups
66
What is in the space between the visceral and parietal pericardium?
Serous fluid to minimise friction
67
During isovolumetric contraction which valves are open?
Both valves are shut
68
During atrial contraction which valves are open?
The aortic valve is shut and the mitral valve is open
69
What is the myocardium?
It is part of the heart wall and it is heart muscle
70
What is the function of the papillary muscles?
To tighten the chordae tendinae by contracting during ventricular systole
71
What effect would an increase in sympathetic activity have on cardiac output?
It would increase contractility, and therefore stroke volume and increase cardiac output
72
On an electrocardiogram, what is the depolarisation of the ventricles represented by?
The QRS complex
73
On an electrocardiogram, what is the depolarisation of the atria represented by?
The P wave
74
On an electrocardiogram, what is the repolarisation of the ventricles represented by?
The T wave
75
Why does blood flow most slowly through capillaries?
Because their total cross sectional area is largest
76
What does the moderator band do?
It is part of the heart's conduction system
