Blood Pressure Flashcards

1
Q

what is blood pressure

A

the outwards (hydrostatic) pressure exerted by the blood on blood vessel walls

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

name the blood pressure; ‘the pressure exerted by the blood on the walls of the aorta and systemic arteries when the heart contracts’

A

systemic SYSTOLIC arterial blood pressure

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

name the blood pressure; the pressure exerted by the blood on the walls of the aorta and systemic arteries when the heart relaxes

A

Systemic DIASTOLIC Arterial Blood Pressure

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

what value should Systemic Diastolic Arterial Blood Pressure not reach or exceed

A

90 mm Hg

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

what value should Systemic Systolic Arterial Blood Pressure not reach or exceed

A

140 mm Hg

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

define hypertension

A

clinical blood pressure of 140/90 mm Hg or higher and day time average of 135/85 mm Hg or higher

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

what is pulse pressure

A

Is the difference between systolic and diastolic blood pressures

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

what is the normal range of values for pulse pressure

A

between 30 and 50 mmHg

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

describe the blood flow in normal arteries

A

laminar- central, not audible

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

when does an artery become completely occluded

A

when external pressure is applied that exceeds the systolic blood pressure- no blood flows through so no sound

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

what happens when the external pressure is kept between systolic and diastolic

A

blood flow becomes turbulent and is now audible through a stethoscope

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

what is the first korotkoff sound

A

peak systolic pressure

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

what are the second and third korotkoff sounds

A

intermittent sounds as blood pressure due to turbulent spurts of flow cyclically exceed cuff pressure

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

what is the fourth korotkoff sound

A

last sound, minimum diastolic pressure (muffled/muted)

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

what is the fifth korotkoff sound

A

no sound as return to laminar flow

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

at which korotkoff sound is diastolic pressure recorded

A

5th as more reproducible, 4th can be interpreted differently

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

at which korotkoff sound is systolic pressure recorded

A

1st

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

why is blood pressure essential

A

the pressure gradient between the aorta and the right atrium drives the blood around the systemic circulation

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

what is the main driving force for blood flow and why

A

MAP (mean arterial pressure) as RA pressure is close to 0

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

how is pressure gradient calculated

A

PG= MAP - central venous (right atrial) pressure (CVP)

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

what does CVP stand for

A

central venous pressure

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

what is mean arterial blood pressure (MAP)

A

the average arterial blood pressure during a single cardiac cycle

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

explain why the formula for MAP = ((2x diastolic) + systolic) / 3

A

As the relaxation (Diastolic) portion of the cardiac cycle is about twice as long as the contraction (Systolic) portion of the cardiac cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are the units for MAP

A

mm Hg

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

what is the second formula for calculating MAP

A

DBP + 1/3 pulse pressure

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

what is a normal range for MAP

A

70-105 mm Hg

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

why is a minimum MAP of 60 mm Hg needed

A

to perfuse the coronary arteries, brain and kidneys

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

how are blood vessels affected by high blood pressure

A

damages vessel walls

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

what is the relationship between MAP, CO and SVR (systemic vascular resistance)

A

MAP= CO x SVR

as CO= SV x HR
MAP= SV x HR x SVR

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

what is systemic vascular resistance

A

the sum of resistance of all vasculature in the systemic circulation

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

what is total peripheral resistance

A

systemic vascular resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what are the major resistance vessels

A

the arterioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what effect does parasympathetic stimulation have on MAP

A

decreases it (as decreases HR and CO)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what effect does sympathetic stimulation have on MAP

A

increases it as increases HR, SV and also increases vasoconstriction in the arterioles and veins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

how does vasoconstriction in the veins increase MAP

A

as increases venous return, SV and CO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

how does vasoconstriction in the arterioles increase MAP

A

increases SVR (TPR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is the role of the baroreceptor reflex

A

short term regulation of mean arterial blood pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what sense changes in MAP

A

baroreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what is the control centre of the Baroreceptor Reflex

A

the medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what are the effectors of the Baroreceptor Reflex

A

heart (HR and SV), blood vessles (SVR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

what does negative feedback act to do

A

minimise any disturbance to controlled variable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

where are the baroreceptors

A

in aortic arch and carotid sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

how do signals from the carotid baroreceptors reach the medulla

A

via the 9th cranial nerve (IXth CN)

44
Q

how do signals from the aortic baroreceptors reach the medulla

A

via the 10th cranial nerve (Xth CN)

45
Q

is the vagus nerve para or symp

A

para

46
Q

what happens to cardiac vagal efferent activity when BP increases

A

increases

47
Q

what are efferent neurons

A

efferent neurons are motor neurons that carry neural impulses away from the central nervous system and towards muscles to cause movement

48
Q

what are afferent neurons

A

Afferent neurons are sensory neurons that carry nerve impulses from sensory stimuli towards the central nervous system and brain

49
Q

what causes postural hypotension

A

when a person stands up from a lying position and the venous return to the heart decreases due to the effect of gravity

50
Q

what happens to MAP during postural hypotension

A

very transiently decreases

51
Q

what does the transient decrease in MAP do to baroreceptors

A

decreases their firing

52
Q

how does the baroreceptors reflex prevent postural hypotension

A

reduce vagal tone to heart and increase sympathetic tone to the heart.

53
Q

what is the role of sympathetic constrictor tone in preventing postural hypotension

A

increases due to decrease in MAP and which increases SVR which increases venous return to the heart and stroke volume

54
Q

during the correction of postural hypotension what does the increase if SVR also cause

A

increased DBP

55
Q

what is the term used to describe venous constriction

A

venoconstriction

56
Q

what type of changes in blood pressure to baroreceptors respond to

A

acute changes

57
Q

what happens to baroreceptors firing when high blood pressure is sustained

A

decreases

58
Q

describe how baroreceptors ‘re-set’

A

will fire again only if there is an acute change in MAP above the new higher steady state level

59
Q

how is MAP controlled mainly in the long term

A

via control of blood volume by hormones

60
Q

how can blood volume and MAP be controlled

A

by controlling the extracellular fluid

61
Q

what does total body fluid consist of

A

Intracellular fluid (2/3rd) + Extracellular Fluid (ECF) - normally 1/3rd of the total

62
Q

what makes up extracellular fluid volume (ECFV)

A

plasma volume (PV) + interstitial fluid (IFV)

63
Q

what is interstitial fluid volume

A

fluid which bathes the cell and acts as the go- between the blood and body cells

64
Q

what happens if plasma volume falls

A

compensatory mechanisms shifts fluid from the interstitial compartment to the plasma compartment

65
Q

how much body weight is fluid normally

A

60%- 20% extra cellular (interstitial fluid) 40% intracellular (intracellular fluid)

66
Q

what two main factors affect extracellular fluid volume

A

water excess or deficit, Na+ excess or deficit

67
Q

why does Na affect extracellular fluid volume

A

as water follows Na+, more sodium = more water

68
Q

what is hormones role in regulating the extracellular fluid volume

A

act as effectors to regulate this by regulating the water and salt balance in our bodies

69
Q

what three hormones regulate long term extracellular fluid volume

A

The Renin-Angiotensin- Aldosterone System - RAAS

Natriuretic Peptides – NPs

Antidiuretic Hormone (Arginine Vasopressin) - ADH

70
Q

what hormone is associated with the most therapeutic interventions

A

renin-angiotensin-aldosterone system RAAS

71
Q

what is the role of RAAS

A

regulates plasma volume and SVR and therefore also MAP

72
Q

what are the three components of RAAS

A

(1) Renin
(2) Angiotensin
(3) Aldosterone

73
Q

what releases renin

A

kidneys

74
Q

what does renin stimulate

A

formation of angiotensin 1 from angiotensinogen

75
Q

what releases angiotensinogen

A

the liver

76
Q

what converts angiotensin 1 to angiotensin 2

A

Angiotensin converting enzyme - ACE

77
Q

what produces ACE

A

pulmonary vascular endothelium

78
Q

what are the 4 things angiotensin 2 stimulates

A

1- release of aldosterone from the adrenal cortex
2-systemic vasoconstriction
3-thrist
4-ADH relsease

79
Q

what is aldosterone and what does it do

A

a steroid hormone that acts on the kidneys to increase sodium and water retention (increases PV and BP)

80
Q

what is the rate limiting step for RAAS

A

renin secretion

81
Q

what is RAAS regulated by

A

mechanisms which stimulate Renin release from the juxtaglomerular apparatus in the kidney

82
Q

what are the mechanisms which stimulates Renin release from the juxtaglomerular apparatus in the kidney

A

1- renal artery hyPOtension
2- stimulation of renal sympathetic nerves
3- decreased Na+ in renal tubular fluid

83
Q

what causes renal artery hypotension

A

systematic hypotension

84
Q

what are natriuretic peptides (NPs)

A

peptide hormones

85
Q

what synthesises NPs

A

the heart (+other organs)

86
Q

what stimulates the release of NPs

A

cardiac distension or neurochemical stimuli

87
Q

what do NPs cause (3)

A

1- excretion of salt and water in the kidneys ( decreased BV and BP)
2- decrease renin release (decrease BP)
3- vasodilators (decrease SVR and BP)

88
Q

what system do NPs provide

A

a counter-regulatory system for RAASystem

89
Q

what are the two types of natriuretic peptides released by the heart

A

atrial natriuretic peptide (ANP) and brain-type natriuretic peptide (BNP)

90
Q

describe ANP, its components, location and course of action

A

28 amino acid peptide synthesised and stored by artial muscle cells (atrial myocytes) until released in response to atrial distension (hypervolemic states)

91
Q

describe ANP, its components and where it is produces

A

32 amino acid peptide synthesised by heart ventricles, brain and other organs

92
Q

describe the production of BNP

A

firstly prepro-BNP (longer chain), which is cleaved to pro-BNP (108 amino acids) and then BNP (32 aa)

93
Q

what is the N terminal piece of pro-BNP called

A

NT-pro-BNP (76 aa)

94
Q

what can be measured in patients with suspected heart failure

A

serum BNP and NT-pro-BNP (measured in the blood)

95
Q

what is vasopressin

A

ADH

96
Q

what is ADH and how is it made

A

Peptide hormone derived from a prehormone precursor synthesised by the hypothalamus

97
Q

where is ADH stored

A

in the posterior pituitary

98
Q

what is secretion of ADH stimulated by

A

(1) reduced extracellular fluid volume(will store water) or (2) increased extracellular fluid osmolality

99
Q

what is the main stimulus of ADH secretion

A

increased extracellular fluid osmolality

100
Q

what is osmolality

A

indicates relative solute-water balance (concentration of solution)

101
Q

what is plasma osmolality measured by

A

osmoreceptors close to the hypothalamus in the brain

102
Q

where and how does ADH act

A

ADH acts in the kidney tubules to increase the reabsorption of water i.e. concentrate urine

103
Q

what would the absorption of water cause

A

would increase extracellular and plasma volume and hence cardiac output and blood pressure

104
Q

how does ADH act on blood vessels

A

causes vasoconstriction - increase SVR and blood pressure

105
Q

when does the vasoconstriction effects of ADH become important

A

hypovolaemic shock (e.g. haemorrhage)