Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOM20002 - HSF > Lecture 56 - Blood Pressure and its Regulation > Flashcards

Lecture 56 - Blood Pressure and its Regulation Flashcards

1
Q

What questions do we ask when we see a patient with low BP?

A
  • Is it genuine hypertension?
  • is the heart rate appropriate for BP?
  • What is the cardiac filling?
  • does the heart contract normally?
  • is the patient abnormally vasodilated?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the factors that effect BP?

A

TPR
CO
Blood volume
Elasticity

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

Describe the generalised tissue structure of veins and arteries

A

Tunica intima
Tunica media
Tunica externa

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

What is special about the structure of arteries?

A

Elastic tissue

For elastic recoil to move blood along the artery

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

Describe the structure of arterioles, and how this relates to the function

A

Smooth muscle
Endothelium

Smooth muscle for resistance

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

Describe the pressure changes from the heart to veins

A 
Heart: Fluctuates from 5-120 mmHg with beating
Arteries: pulse: 120/80 mmHg
Arterioles: drops, pulse present
Capillaries: around 40 mmHg
Veunles: around 20
Veins: 20 down to 0
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is pulse pressure?

A

Strength of the pressure wave

Sys. - Dys.

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

What is MAP?

A

Average pressure responsible for driving blood forward

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

What unit is used to measure BP?

A

mmHg

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

What is driving pressure?

A

Pressure that pushes blood forward

Generated by the heart

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

What is transmural pressure?

A

Pressure difference between inside of vessels and outside of vessels

eg. Brain in skull: skull means that there is high transmural pressure

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

What is hydrostatic pressure?

A

Pressure in a column of water due to the height of the liquid

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

What are the origins of pressure in circulation?

A

Gravity
Compliance
Viscous resistance
Inertia

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

When does gravity affect pressure?

A

Gravity affects hydrostatic pressure when there is a height difference

ie when standing

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

Does gravity affect driving pressure?

A

No

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

What is the difference in pressure of the arteries and veins when standing and lying at any given point on the body?

A

85 mmHg

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

What is compliance?

A

The ‘expandability’ of the walls of the vessel

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

What sort of container has zero compliance?

What happens when we keep adding liquid to this container?

A

eg. A steel tube

Pressure increases
Volume does not increase

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

What happens when we add liquid to a container with infinite compliance?

A

Increase in volume

Pressure remains at zero

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

What happens when we add liquid to a container with finite compliance?

A

Increase in volume
Increase in pressure

(walls can expand)

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

Change in pressure with a given change in volume is greater if the compliance of the vessel is…

A

Lower

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

What is viscous resistance?

A

Sticky fluid stick to the side of the vessel and thus exert resistance.

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

What does blood viscosity depend on?

A 
Fibrinogen concentration
Hematocrit
Vessel radius
Linear velocity
Temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How does vessel radius affect blood viscosity?

A

Lesser radius, greater viscosity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How does temperature affect blood viscosity?

A

Greater temperature, lower viscosity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does the law of conservation of energy say about fluid pressure and velocity?

A

When blood velocity increases, fluid pressure must decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What causes the decrease in pressure of the blood when blood velocity increases?

A

Inertia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is ‘Z’?

A

Impedance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What does vascular impedance depend on?

A

Flow resistance
Compliance
Inertiance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

According to Poiseuille’s law, what is resistance affected by?

A

Length of tube
Viscocity
Radius of tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is conductance?

A

Inversely proportional to resistance

Bloop flow through a vessel at a given pressure difference

32
Q

Where is total resistance highest?

Why?

A

Arterioles

33
Q

Why is it important for the walls of the arteries to be elastic?

A

When blood flow in, the wall stretches out.

The elastic recoil then pushes the blood forward.

The elastin stretching is stored potential energy that is converted into kinetic energy

34
Q

What happens when MAP is too high or low?

A

Low: dizziness, organ failure

High: stroke, aneurysm

35
Q

What things determine MAP?

A

MAP = CO x TPR
(Cardiac output
TPR)

Also:

  • total blood volume
  • HR
  • SV
36
Q

Why must flow into a segment equal flow out?

A

If this is not maintained, BP will either be too high or too low.

37
Q

How is MAP calculated?

A

1/3(sys - dys) + dys

38
Q

What is DP?

A

Pressure gradient

ie P1 - P2

39
Q

What functions does the movement of blood fulfill?

A

Heat transport
Gas
Nutrient
Wastes

40
Q

What things help the movement of blood?

A 
Heat (energy source)
Elastic tissue
Gravity
Skeletal muscle
Diaphragm

Of course, heart contraction

41
Q

What is normal CO?

A

5 L/min

42
Q

What is normal SV?

A

Stroke volume

70 mL

43
Q

How is SV calculated?

A

EDV - ESV

End diastolic volume - End systolic volume

44
Q

What factors affect stoke volume?

A
  • preload
  • contractility = inotropy
  • afterload
45
Q

What is preload?

A

EDV: end diastolic volume

What is there before systole

46
Q

What is afterload?

A

ESV: end systolic volume

What is left after systole

47
Q

Explain the Frank-Starling Law

A

As EDV increases, SV increases.

The greater the stretch of the cardiac muscle, ie the more blood coming into the heart, the heart will eject more blood in the next stroke.

48
Q

At any one time, what percentage of blood is in the veins?

How about arteries?

A

Veins: 64%
Arteries: 13%

49
Q

What determines preload?

A

Venous return determines EDV

50
Q

What factors affect venous return?

A 
Muscle pumps
Respiratory pump
Neural control
(sympathetic tone
vasoconstriction)
51
Q

How does noradrenaline affect EDV?

A

NA increases EDV and thus SV

52
Q

What does increased afterload mean?

A

decreased SV

Increased ESV

53
Q

What does increased inotropy mean?

A

Increased SV

Decrease ESV

54
Q

What does increased proload mean?

A

Increased SV

Increased EDV

55
Q

What things control the heart rate?

A

Neural:

  • Intrinsic: autorhythmic cells
  • Extrinsic: ANS
56
Q

Describe the sympathetic effect on HR

A

Increases contraction of the heart by:

  • changing ion permeability
  • so that the cells reach threshold potential sooner
  • depolarisation
57
Q

Describe the parasymathetic effect on HR

A

Decreased contraction rate of the heart by:
- changing ion permeability
- so that the cells take longer to reach threshold
(hyperpolarisation)

58
Q

Which cells does the sympathetic and parasympathetic act on?

A

B-adrenoceptors and mAChR

Conduction through the internodal pathways

59
Q

What happens to MAP when there is a decrease in TPR?

A

Decrease in MAP

60
Q

What does an organ do to achieve greater blood supply?

A

Decreased arterial resistance

Relaxation of arterial smooth muscle

61
Q

What compensatory mechanisms are effected to compensate for low MAP?

A

Increase CO
Increased TPR
Increased HR
Increase SV

62
Q

What happens when CO decreases?

A

Pooling of blood in the legs

63
Q

How does the body monitor CO?

A

pH
CO2
O2
BP

64
Q

How is BP regulated over the short term?

A

Neural (ANS)

Baroreceptor reflex

65
Q

Describe the baroreceptor reflex when standing up

A
  1. Decreased stretch detected by baroreceptors
  2. Central integration
  3. Activation of Sym. and deactivation of Parasym.
  4. Increased:
    - HR
    - Force of contraction
    - TPR
    4b. Decreased:
    - atrioventricular conduction time
66
Q

Where are the baroreceptors located?

A

Carotid sinus

Aortic arch

67
Q

What are the normal effects of the parasympathetic division on the heart

A

Decreased HR

Increased antrioventricular conduction time

68
Q

Describe the baroreceptor reflex when lying down

A
  1. Excess stretch detected by baroreceptors
  2. Central integration
  3. Activation of Parasym. and deactivation of Sym.
  4. Increased:
    - AV conduction time
    4b. Decreased:
    - TPR
    - HR
    - Force of contraction
69
Q

What do chemoreceptors detect?

A

Low pH

Low O2

70
Q

What does low O2 and high pH stimulate?

A

Increased respiration rate

Increased BP

71
Q

How is BP regulated over the long-term?

A
  1. Cardiac Output
    - hormonal
    - renal
  2. TPR
    - hormonal
    - vascular structure
72
Q

How do we increase CO over the long-term?

A

Increased ECF

Decreased renal salt excretion

73
Q

How do we increase TPR over the long-term?

A

Hypertrophy of arterial wall

Vasoconstrictive hormones

74
Q

Which receptors detect low BP?

A

Atrial baroreceptors

75
Q

Describe the function of atrial baroreceptors

A

Monitor changes in central blood volume

–> Thirst stimulated

BIOM20002 - HSF (60 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions