Blood Pressure 1 Flashcards

1
Q

Degree of constriction
experienced by a blood
vessel relative to…

A

… its maximally dilated state.

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

What is vascular smooth muscle?

A

vascular tone (vascular tonus).

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

Which units are used to measure blood pressure?

A
  1. Bar
  2. PSI (pound per square inch)
  3. mm Hg – millimetre of mercury
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define blood pressure?

A

pressure exerted by circulating blood upon the walls of blood vessels. Force applied to the vessel walls.

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

What is the flow rate of blood?

A

volume of blood flowing through a specific vessel – or organ – over a period of time (for example, L/min, mL/s, etc.)

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

Flow is directly proportional to…

A

… pressure gradient

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

Flow is inversely proportional to …

A

… vascular resistance.

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

What is vascular resistance?

A

Frictional force that opposes the flow of a fluid

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

Increased resistance =

A

decreased flow rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

decreased resistance =

A

increased flow rate

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

How can the body compensate for increased
resistance?

A

Heart works harder to achieve a larger
pressure gradient

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

the flow rate of blood through a vessel is…

A

… the volume of blood passing thorugh per unit of time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

the flow rate of blood thorugh a vessel is directly proportional to…

A

… the pressure gradient (as the pressure gradient increases, flow rate increases.

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

the flow rate of blood is inversely proportional to …

A

… vascular resistance (as resistance increases, flow rate decreases).

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

flow rate of blood through a vessel =

A

pressure gradient / resistance of blood vessel.

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

What causes resistance to blood flow?

A
  1. Blood viscosity
  2. Vessel dimensions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is blood viscosity?

A

The ‘thicker’ a liquid, the more viscous it is

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

What causes resistance to blood flow?

A
  1. Vessel dimensions
    Length
    Radius

Blood ‘rubbing’ - the greater the contact area = the greater the ressitance

‘rubbing against arterial walls.

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

More blood in contact with the walls of a narrow vessel =

A

increased resistance - flow decreases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Less blood in contact with the walls of a wide vessel =

A

decreased resistance. Flow increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Slight change in the radius of a vessel =

A

notable change in flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Poiseuille law

A

Flow = pi x pressure gradient x radius^4

/

8 x viscosity x length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Resistance is inversely proportional to…

A

… the fourth power of the
radius

24
Q

Doubling the radius reduces resistance to…

A

1/6th its orginal value

25
Q

flow is…

A

… 16 fold

26
Q

What is pulse pressure?

A

PP = systolic pressure – diastolic pressure (DP)

in simple terms

27
Q

Pulse pressure represents…

A

It represents the force that the heart generates each time it contracts
(Amount of pressure required to create the feeling of a pulse)

28
Q

MAP = clinically defined as

A

Perfusion pressure

29
Q

MAP is normally between…

A

70 to 110 mmHg

30
Q

If MAP falls significantly…

A

organ will not receive enough blood flow -> resulting in ischemia.

31
Q

cross sectional area is related to…

A

… velocity

32
Q

velocity is inversely proportional to …

A

… cross sectional area.

33
Q

what is cardiac output?

A

volume of blood pumped by the heart

34
Q

Cardiac output (CO) = ?

A

CO = Heart Rate X Ventricle Stroke Volume = dm3/min, L/min

35
Q

What is peripheral resistance?

A

resistance of arteries and
arterioles to blood flow

36
Q

What results in changes in blood pressure?

A

Any factor causing a change in cardiac output or peripheral resistance will result in a change in blood pressure.

37
Q

Factors affecting heart rate?

A

o2 and co2
Phyiscal activity
Hct
Symp and paraymp activity
body comp
drugs
dehydration
adrenaline adn other hormones
adenosine and caffeine
pH
electrolytes
prostaglandins

38
Q

Factors affecting heart rate (HR)?

A

Autonomic innervation
Hormones
fitness levels
age

39
Q

What factors affect stroke volume?

A

Heart size
Fitness levels
gender
contratility
duration of contraction
preload (EDV)
Afterload (resistance)

40
Q

How to calculate stroke volume?

A

Stroke volume (SV) = EDV - ESV

41
Q

How to calculate cardiac output?

A

Cardiac output (CO) = HR x SV

42
Q

What is vascular compliance?

A

Ability of a blood vessel wall to expand and contract passively with changes in pressure.

43
Q

whats vascular compliance?

A

Ability of a blood vessel wall to expand and contract passively with changes in pressure

44
Q

What is aortic aneurysm a result of?

A

of increased total peripheral resistance.

45
Q

An increase in cardiac output leads to…

A

…an increase in the volume of blood contained in the aorta and an increase in mean arterial pressure when total peripheral resistance remains the same

46
Q

a constant cardiac output leads to…

A

… an increase in the volume of blood contained in the aorta and an increase in mean arterial pressure when total peripheral resistance increases.

47
Q
A
48
Q

aortic aneurysms have a limited…

A

…vascular compliance

49
Q

aortic aneurysm affect on aorta?

A

Enlargement (dilatation) of the
aorta to greater than 1.5 times
normal size.

50
Q

Aortic aneurysm is often…

A

…asymptomatic -> high risk of death

51
Q

what are some occasional symptoms of aneurysms?

A

Occasionally, abdominal, back, or
leg pain.

52
Q

Aortic aneurysm most commonly located in…

A

… abdominal aorta, but can be located in the thoracic aorta.

53
Q

describe the distribution of blood within the circulation?

A

the greatest volume found in venous vasculature, where 70-80% of blood is found. FOr this reason, veins are referred to as capacitance vessels. The relative volume of blood between arterial and venous sides of the circulation can vary considerably depending upon total blood volume, intravascular pressures, and vascular compliance.

54
Q
A
55
Q

blood distribution values?

A

vein = 65%
arteries = 13%
arterioles = 2%
capilleries = 5%
central blood volume = 15%

56
Q

what is central blood volume (CBV)?

A

Central blood volume (CBV) = blood in heart cavities + lungs
+ central arterial tree.

57
Q

CBV increased during …

A

… sympathetic stimulation