blood pressure Flashcards
(53 cards)
1
Q
what is arterial blood pressure?
A
a measure of force to push blood around the body
2
Q
what is systolic blood pressure?
A
pressure in arteries during systole (contraction)
3
Q
what is diastolic blood pressure?
A
pressure in arteries during diastole (relaxation)
4
Q
how would you calculate pulse pressure?
A
systolic BP- diastolic BP
5
Q
how would you calculate mean arterial pressure?
A
diastolic blood pressure + 1/3 pulse pressure
6
Q
what is the mean arterial blood pressure?
A
- Driving force for blood flow through organs (except lungs)
- Maintenance is essential for ensuring adequate blood flow to organ systems
- Arterial blood pressure is maintained at around 120 / 80mmHg
- Variations in blood flow to different organs must occur when demand arises to ensure adequate perfusion.
- Arterial blood pressure provides a useful insight into a patient’s cardiovascular health
- Routinely measured in clinical practice.
7
Q
what is mean systemic arterial pressure a product of?
A
cardiac output and total peripheral resistance
8
Q
when is blood pressure greatest?
A
on waking up
9
Q
when is blood pressure lowest?
A
during sleep
10
Q
when does blood pressure increase?
A
in response to exercise, stress, sensory stimuli
11
Q
what is blood pressure measured using?
A
sphygmomananometer
12
Q
what are korotkoff sounds?
A
the sounds that medical personnel listen for when they are taking blood pressure using a non-invasive procedure
13
Q
what are korotkoff sounds?
A
the sounds that medical personnel listen for when they are taking blood pressure using a non-invasive procedure
14
Q
why are the cuffs inflated when measuring blood flow?
A
stops the artery blood flow
15
Q
what are the two mechanisms which control and regulate blood pressure?
A
rapid and long term
16
Q
what is the rapid regulation of blood pressure?
A
nerves and hormones
17
Q
what is the long term regulation of blood pressure?
A
blood volume
18
Q
where do pressure gradients exist in relation to blood pressure?
A
from the arterial system to venous system
19
Q
when is blood pressure highest in relation to the heart?
A
when it enters the aorta on contraction of the left ventricle
20
Q
what are baroreceptors?
A
- Mechanoreceptors that detect the degree of stretch of blood vessel walls
- Monitor blood pressure
- Mechanical stretch (circumferential stress) in arteries occurs due to pulsatile blood flow
- Directly related to blood pressure
- Increases during systole
- Gradually reducing during diastole.
- Most abundant in the aortic arch and carotid sinus.
- Sensitive to changes in stretch (pressure)
- Also sensitive to the rate of pressure change
21
Q
where is it extremely important to monitor blood pressure?
A
entering the head and neck
22
Q
what is the carotid sinus?
A
the area with a large number of branching nerve endings in a thin artery which comes from a carotid artery
22
Q
what is the carotid sinus?
A
the area with a large number of branching nerve endings in a thin artery which comes from a carotid artery
23
Q
what is the aortic arch?
A
where the aorta comes out the heart
24
what are carotid sinus baroreceptors innervated by?
the sinus nerve of Hering
25
what are the baroreceptors of the aortic arch innervated by?
the aortic nerve and vagus nerve- these baroreceptors have a higher theshold pressure so are less sensitive to chages in strecth
26
what is the sinus nerve of Hering?
a branch of the Glossopharyngeal nerve
27
what happens if baroreceptors detect a decrease in arterial pressure?
- reduced action potential firing from baroreceptors
- stimulation travels along afferent neurons
- to the medullary cardiovascular centre
- increased stimulation of sympathetic neurons to heart/vein/arteries
- decreased stimulation of parasympathetic neurons to heart
28
what happens if baroreceptors detect an increase in arterial pressure?
- increased action potential firing from baroreceptors
- stimulation travels along afferent neurons
- to the medullary cardiovascular centre
- decreased stimulation of sympathetic neurons to heart/vein/arteries
- increased stimulation of parasympathetic neurons to heart
29
what is the valsava manoeurve?
- breathing method through nose to attempt to expire against a closed glottis
- associated with, exhaling when mouth & nose are closed e.g. lifting of heavy weights
30
physiological response of the valsalve manoeuvre
1) Increased intrathoracic pressure
2) Raising blood pressure; normal LV contraction + (1); increased baroreceptor firing
3) Heart rate falls transiently – impeding venous return of blood to heart
4) Fall in CO and MAP
5) As MAP decreases, HR rises and (w/TPR), stabilises blood pressure
When the glottis (pharynx) is re-opened to allow expiration;
6) Intrathoracic pressure falls
7) BP falls initially
8) Venous return is rapidly restored
9) EDV & CO increase, raising BP
10) Increased BP is sensed by baroreceptors results in reflex bradycardia (slowing of HR)
31
what happens to the threshold for baroreceptor activity when the atrial blood pressure is elevated for a prolonged period >15mins?
rises to a higher value
32
how effective are baroreceptors as moniters?
Ineffective monitors of absolute pressure of blood in carotid arteries to the brain
Short – term regulators of blood pressure only
33
how effective are baroreceptors as moniters?
Ineffective monitors of absolute pressure of blood in carotid arteries to the brain
Short – term regulators of blood pressure only
34
describe the resetting of baroreceptor sensitivity
During exercise – Maintains Cardiac Output as heart rate does not fall in response to increase in BP accompanying exercise
Hypertension – aids buffering of acute fluctuations in BP at new higher BP level
35
what are influences on blood volume?
Venous pressure
Venous return
End – diastolic volume
Stroke Volume
Cardiac Output
36
what are influences on blood volume?
Venous pressure
Venous return
End – diastolic volume
Stroke Volume
Cardiac Output
37
what happens to blood plasma volume when artery pressure increases?
decreases via increasing renal excretion of salt and water
38
what happens to arterial pressure when blood volume increases?
increases
39
what are arterioles?
- small diameter blood vessels
- small changes in arteriolar radius control blood pressure in response to locally circulating substances
40
what happens if pressure decreases in arterioles?
- sympathetic nerves
- noradrenaline
- constriction
41
what happens if pressure increases in arterioles?
- sympathetic cholinergic nerves
- acetylchloine
- muscarinic receptors
- plasma
- adrenaline
- local controls
- increased potassium ions
- increased adenosine
- decreased PO2
- dilation
41
what happens if pressure increases in arterioles?
- sympathetic cholinergic nerves
- acetylchloine
- muscarinic receptors
- plasma
- adrenaline
- local controls
- increased potassium ions
- increased adenosine
- decreased PO2
- dilation
42
what is capillary fluid shift?
Occurs due to venous dilators
Caused by reduced proximal capillary hydrostatic pressure
Most vasodilators have effects on both arteries and veins
43
where do mechanisms that locally regulate long term blood pressure originate via?
Renin – Angiotensin – Aldosterone System (RAAS)
Blood vessels (myogenic or endothelial factors)
Maintenance of constant blood flow
Blood volume and fluid regulation
44
where do mechanisms that locally regulate long term blood pressure originate via?
Renin – Angiotensin – Aldosterone System (RAAS)
Blood vessels (myogenic or endothelial factors)
Maintenance of constant blood flow
Blood volume and fluid regulation
45
what is hypertension?
Clinic blood pressure of 140 mmHg Systolic and 90 mmHg Diastolic (140/90) or higher
Blood pressure increases with age
Usually Hypertension lacks noticeable symptoms, until very severe
Lifestyle changes and / or pharmacological intervention can lower blood pressure
46
what factors increase the risk of hypertension?
Underlying health condition (kidney disease, diabetes, hormone problems etc.)
Age
Cigarette smoking
High salt intake
Lack of exercise
Being overweight
Regularly drinking large amounts of alcohol
Stress
Genetic predisposition
Family history
47
what therapeutics can increase the risk of hypertension?
Contraceptive pill
Non-steroidal anti-inflammatory drugs (NSAIDS)
Recreational drugs (e.g. cocaine and amphetamines)
48
what are consequences of hypertesnsion?
The damage caused by prolonged Hypertension can lead to significant clinical consequences :
Aneurysms in cerebral arteries
Left Ventricular Hypertrophy (LVH)
Thickening of arteries
Atherosclerosis deterioration
These effects may lead to;
Renal Disease
Development of heart failure due to myocardial adaptation to compensate for LVH
Malignant Hypertension – Severely high BP
Angina or Myocardial Infarction (Cardiac Ischaemia)
Stroke
49
what are consequences of hypertesnsion?
The damage caused by prolonged Hypertension can lead to significant clinical consequences :
Aneurysms in cerebral arteries
Left Ventricular Hypertrophy (LVH)
Thickening of arteries
Atherosclerosis deterioration
These effects may lead to;
Renal Disease
Development of heart failure due to myocardial adaptation to compensate for LVH
Malignant Hypertension – Severely high BP
Angina or Myocardial Infarction (Cardiac Ischaemia)
Stroke
50
what is hypertensions relation to dentistry?
Many anti – hypertensive drugs have interactions with local anaesthetics and analgesics- May lead to local anaesthetic toxicity
Dental treatment is stressful for many patients and any increase in BP may lead to acute complications, e.g., Myocardial Infarction or Stroke
Thus, dental patients with CV Disease have associated higher risk of complications due to release of endogenous catecholamines due to pain/stress
Crucial that Dental practitioners obtain an up-to-date medical history prior to commencing treatment.
51
what is hypotension?
Blood pressure
Systolic = 90 mmHg
Diastolic = 60 mmHg
90/60 mmHg
Postural Hypotension (Orthostatic Hypotension) is an abnormal drop in blood pressure when individual stands up after sitting/lying down
Symptoms: Dizziness, light – headedness, fainting, possible fall
May be asymptomatic
More common in older people and those with certain underlying conditions that affect (Sympathetic or Parasympathetic nervous system)
Parkinson’s disease or Diabetes
May also be caused by dehydration or certain medicines (e.g., some anti-hypertensives
