S1: structure and function of CVS Flashcards

1
Q

What is the course of blood flow into and out of the heart through the major vessels?

A

The right side of the heart consists of the right atrium which receives deoxygenated blood from the body and the right ventricle which pumps the deoxygenated blood out through the pulmonary artery to the lungs. The left side of the heart consists of the left atrium which receives oxygenated blood from the lungs and the left ventricle which pumps the oxygenated blood out through the aorta to the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does the pericardium enclose?

A

The heart and roots of the great vessels are enclosed by a fibroserous sac called the pericardium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the two layers of the pericardium?

A

Fibrous pericardium = strong, outer fibrous layer made of tough connective tissue
-prevents overfilling of the heart
Serous pericardium = two different layers: visceral & parietal
-outer parietal layer: lines the internal surface of the fibrous pericardium
-internal visceral layer: forms the outer layer of the heart (epicardium)
-between the two layers there is a small amount of lubricating serous fluid (heart beats in a minimised friction environment)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is in between the two layers of the pericardium? What is the function?

A

The space between the visceral and parietal layers contains a thin film of pericardial fluid that allows the heart to beat in a minimal-friction environment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the four recognised borders of the heart?

A

Right
Left
Inferior
Superior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the four borders of the heart

A

Left border = left ventricle (& some of left atrium)
Right border = right atrium
Superior border = right and left atria (& great vessels)
Inferior border = left and right ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe problems associated with accumulation of fluid in the pericardial sac

A

Rapid fluid accumulation in the pericardium can cause cardiac tamponade, a severe compression of the heart that impairs its ability to function
Cardiac tamponade resulting from pericardial effusion can be life-threatening.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the relationship between the pericardium and the phrenic nerves

A

Sensory fibres from the phrenic nerve supply the central part of the diaphragm, including the surrounding pleura and peritoneum. The nerve also supplies sensation to the mediastinal pleura and the pericardium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the three layers that large blood vessels have and their structure?

A
Tunica intima – consists of endothelium and the internal elastic lamina.
Tunica media – smooth muscle with elastic fibres. This layer is responsible to vasoconstriction and vasodilation.
Tunica adventitia (also called externa) – connective tissue consisting of collagen and elastic fibres. It can anchor the vessel to nearby structures.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the cardiac / thoracic ratio?

A

The cardiothoracic ratio is the ratio of the transverse diameter of the heart to the maximum internal diameter of the thoracic cavity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does an increased cardiac / thoracic ratio mean?

A

Increased cardiothoracic ratio describes widening of the cardiac silhouette on a chest radiograph. This is of use when making an assessment of a PA chest x-ray since the AP chest x-ray causes the artefactual magnification of the heart and the cardiothoracic ratio is altered.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What different imaging techniques can be used to assess cardiac structure and functioning?

A
X-rays
Ultrasound
Nuclear
CMR 
CT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define haemodynamics

A

Physical factors that control blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the difference between serum and plasma?

A

Plasma is the fluid collected from unclotted blood

Serum is the fluid collected from clotted blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Name some diseases where whole blood viscosity changes

A

Polycythaemia
Thrombcythaemia
Leukaemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define flow

A

Volume transferred per unit time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define pressure

A

Force per unit area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define resistance

A

Measure of difficulty of flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the relationship between flow, conductance and pressure difference?

A
F = K * P
F = flow
K = conductance
P = change in pressure
20
Q

What is Darcy’s law and what is it similar to?

A

Flow = change in pressure / resistance

Analogous to Ohm’s law (I = V/R)

21
Q

What is vascular resistance?

A

Resistance to flow in blood vessels

22
Q

What is the relationship between flow and resistance?

What is the relationship between resistance and change in pressure?

A

Flow and resistance are reciprocally related (if one goes up the other one goes down)
At any given flow, increased resistance = increase in pressure gradient

23
Q

What is laminar flow?

A

Laminar flow is smooth, silent maintaining energy
Typical of most arteries, arterioles, venules and veins
Moves in ‘stream lines’ = centre has the greatest velocity

24
Q

What is turbulent flow?

A

Turbulent flow is disorganised and noisy

Energy is lost

25
Q

Causes of turbulent flow

A

Branching of a vessel
Change in direction of blood
Stenosis (eg. atheroma building up in a vessel)

26
Q

Define stenosis

A

Abnormal discrete narrowing of an artery or open area of a heart valve

27
Q

What is Reynolds number?

A

There is a pressure increase beyond which flow can match it linearly

28
Q

What are the main factors of resistance to flow?

A

Diameter
Length of vessel
Viscosity

29
Q

What contributes the greatest component of total peripheral resistance?

A

Smallest arteries and arterioles = biggest jump in pressure across vessel class

30
Q

Define velocity

A

The distance fluid moves in a given time

31
Q

Why is lower velocity useful in capillaries?

A

Diffusion of nutrients

Delivering of oxygenated blood

32
Q

What is pulse pressure?

A

The difference between systolic blood pressure and diastolic blood pressure
PP = SBP - DBP

33
Q

What is mean arterial pressure?

A

MAP = DBP + 1/3 PP

34
Q

What is the relationship between cardiac output, heart rate and stroke volume?

A

CO = HR * SV

35
Q

What is the relationship between mean arterial pressure, cardiac output and total peripheral resistance?

A

MAP = CO * TPR

36
Q

Define pulse

A

Shock wave that arrives slightly before the blood itself

37
Q

What factors govern pulse pressure?

A

Volume of blood ejected

Compliance of the arterial system

38
Q

What is a strong pulse described as and reasons why someone may have one?
What is a weak pulse described as?

A

Strong pulse = bounding
Bradycardia, vasodilation and elite athletes
Weak pulse = thready

39
Q

Relating to blood flow, what can be heard and what can be felt?

A

THRILL can be felt

BRUIT can be heard

40
Q

What are the names of the sounds generated when a blood pressure cuff changes the flow of blood through the artery?

A
Korotkoff sounds 
(change from laminar flow to turbulent flow)
41
Q

Describe taking blood pressure using a cuff

A

1) pressure in cuff > systolic pressure: no blood flow can take place
2) pressure in cuff < systolic pressure: blood can begin to flow, but artery is partially compressed -> flow is turbulent and korotkoff sounds can be heard
3) pressure in cuff < diastolic pressure: sounds will disappear as blood can now flow in a laminar fashion

42
Q

What is the effect of gravity on blood pressure?

A

Pressure below the level of the heart greater and above the level of the heart lower
Effects of gravity maintains a pressure gradient allowing blood flow from heart to foot when standing
Pooling of blood occurs below the level of the heart upon standing in the venous system
Postural hypotension: dizziness upon standing -> lower stroke volume

43
Q

Factors that affect venous pressure

A

Venous constriction
Changing body position
Total peripheral resistance
Cardiac output

44
Q

Factors that affect arterial pressure

A

Total peripheral resistance

Cardiac output

45
Q

Name the 5 surfaces of the heart

A
Anterior = right ventricle 
Inferior = left and right ventricles 
Posterior = left atrium 
Right pulmonary = right atrium 
Left pulmonary = left ventricle
46
Q

List 4 functions of the pericardium

A

Fixes the heart in the mediastinum and limits its motion
Prevents overfilling of the heart
Lubrication
Protection from infection