Brainscape's Knowledge GenomeTM

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


See full index

Feedback control & physiology > Control of arterial blood pressure > Flashcards

Control of arterial blood pressure Flashcards

1
Q

what are korotkoff sounds?

A

the sounds heard when doing blood pressure

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

what is record systolic blood pressure and record diastolic blood pressure?

A

record systolic = 1st appearance of sound
record diastolic = point where sound disapears

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

what drives blood around systemic circulation?

A

a pressure gradient between the aorta and RA drives blood

  • since RA pressure is close to 0 →driving force for blood flow is MAP (mean arterial blood pressure)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how to calculate pressure gradient?

A

mean arterial blood pressure - central venous (RA) pressure (CVP)

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

what is systemic vascular resistance?

A

sum of resistance of all vasculature in systemic circulation

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

what are 2 common areas for baroreceptors?

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

what happens in normal baroreceptor reflexes in prevention of postural hypotension?

A

when normal person stands up from sitting:

  • venous return of heart decreases - effect of gravity
  • MAP very transiently decreases
  • this reduces the rate of firing of baroreceptors
  • vagal tone to heart decreases and sympathetic tone to heart increases, this increases the HR and SV
  • the sympathetic constrictor tone increases, this increases the systemic vascular resistance - arterioles are main SVR site
  • sympathetic constrictor tone to veins increases the venous return to heart & SV

= the result is rapid correction of transient fall in MAP (HR increase, SV increase, SVR increase)

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

what is postural hypotension?

A

results from failure of baroreceptor responses to gravitational shifts in in blood, when moving from horizontal to vertical position

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

what are risk factors for postural hypotension?

A
  • age related
  • medications
  • certain diseases
  • reduced intravascular volume
  • prolonged bed rest
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is a positive result for postural hypotension?

A

a positive result is indicated by a drop within 3 minutes of standing from lying position

  • in systolic blood pressure of at least 20 mmHg (with or without symptoms)
  • a drop in diastolic blood pressure of at least 10 mmHg (with symptoms)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are symptoms of postural hypotension?

A

lightheadedness, blurred vision, faintness, dizziness, falls

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

what do baroreceptors only respond to?

A

acute changes in blood pressure

  • Baroreceptors “re-set” - they will fire again only if there is an acute change in MAP above the new higher steady state level
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how can blood volume of MAP be regulated?

A

regulating the extracellular fluid volume
→plasma volume and hence steady state blood volume and MAP would be regulated if ECFV is regulated

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

what is extracellular fluid?

A

plasma volume (PV) + Interstitial fluid volume (IFV) →this is the fluid which bathes the cells and acts as the go between the blood & body cells

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

what does body do if plasma volume falls?

A

compensatory mechanisms shift fluid from interstitial compartment to plasma compartment

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

what are the 2 main factors that affect extracellular fluid volume?

A
  1. water excess or deficit
  2. Na+ excess or deficit
17
Q

what regulates the extracellular fluid volume (including plasma volume) and how?

A

Hormones act as effectors to regulate the extracellular fluid volume (including Plasma Volume) by regulating the Water and Salt Balance in our bodies

= Healthy people stay in a stable water and salt balance, where water input = water output

18
Q

what are the 3 main hormone mechanisms that regulate extracellular fluid volume?

A
  1. renin-angiotensin-aldosterone- system = RAAS
  2. Natriuretic Peptides – NPs
  3. Antidiuretic Hormone (Arginine Vasopressin) - ADH
19
Q

what happens in RAAS hormone regulation?

A

renin = released from kidneys & stimulates formation of angiotensin 1 in the blood from angiotensinogen (produced by liver)

angiotensin 1 is converted to angiotensin 2 by angiotensin converting enzyme - ACE (mainly produced by pulmonary vascular endothelium)

angiotensin 2
1. stimulates release of aldosterone from adrenal cortex
2. causes systemic vasoconstriction → increases SVR
3. also stimulates thirst and ADH release i.e. contributes to increasing plasma volume mainly brought about by aldosterone

aldosterone (steroid hormones) acts on kidneys to increase Na+ and water retention = increases plasma volume

20
Q

what is purpose of RAAS?

A

to increase plasma volume (which makes more fluid and increases pressure)

21
Q

what are the 3 results of angiotensin 2?

A
  1. vasoconstriction (increases SVR and blood pressure)
  2. increases ADH release and increase thirst (increases plasma volume and blood pressure)
22
Q

what is the rate limiting step for RAAS?

A

renin secretion

23
Q

what releases renin? (specifically)

A

in kidney = Juxtaglomerular apparatus is a region comprising the macula densa, extraglomerular mesangial cells and granular cells release renin

24
Q

what is renin angiotensin aldosterone system (RAAS) regulated by?

A

regulated by mechanisms which stimulates renin release from juxtaglomerular apparatus in kidney:

  1. Renal artery hypotension -caused by systemic hypotension (↓ blood pressure)
  2. stimulation of renal sympathetic nerves
  3. Decreased [Na+] in renal tubular fluid – sensed by macula densa (specialised cells of kidney tubules)
25
Q

describe what happens in natriuretic peptides to regulate extracellular fluid volume?

A

peptide hormones (synthesised by heart - and brain & other organs) are released in response to cardiac distension (stretching) or neurohormonal stimuli

  • they cause excretion of salt & water in kidneys, thereby reducing blood volume & blood pressure

decrease renin release = decrease blood pressure
act as vasodilators = decrease SVR & blood pressure

  • NP’s provide a counter-regulatory system for RAAS
26
Q

what are the 2 types of natriuretic peptides?

A
  1. atrial natriuretic peptide (ANP)
  2. brian type natriuretic peptide (BNP)
27
Q

what is atrial natriuretic peptide?

A

ANP - 28 amino acid peptide synthesised and stored by atrial muscle cells (atrial myocytes)

→it’s released in response to atrial distension (hypervolemic states= decreased volume of blood circulating in body)

28
Q

what is brain type natriuretic peptide?

A

BNP is a 32 amino acid peptide synthesised by: heart ventricles, brain (where it was originally identified) and other organs

  • BNP is first synthesised as prepro-BNP, which is then cleaved to pro-BNP (108 amino acids) and finally BNP (32 amino acids)
  • Serum BNP and the N-terminal piece of pro-BNP (NT-pro-BNP, 76 amino acids) can be measured in patients with suspected heart failure
29
Q

what is ADH?

A

antidiuretic hormone - also called vesopressin

Peptide hormone derived from a pre-hormone precursor synthesised by the hypothalamus and stored in the posterior pituitary

30
Q

what is secretion of ADH stimulated by?

A
  1. reduced extracellular fluid volume
  2. increased extracellular fluid osmolality (main stimulus)

ADH release is stimulated by increased plasma osmolality

31
Q

what does plasma osmolality indicate?

A

relative solute-water balance

32
Q

what is plasma osmolality monitored by?

A

monitored by osmoreceptors mainly in the brain in close proximity to hypothalamus

33
Q

what does ADH do?

A
  • acts in the kidney tubules to increase the reabsorption of water (conserve water) - i.e. concentrate urine (antidiuresis)
  • This would increase extracellular and plasma volume and hence cardiac output and blood pressure
  • also acts on blood vessels to cause vasoconstriction - increase SVR and blood pressure: the effect is small in normal people but becomes important in hypovolaemic shock (e.g. haemorrhage)
34
Q

what are the factors of Fick’s law of diffusion?

A

Fick’s law of diffusion describes the rate at which a gas or solute diffuses across a fluid membrane

factors:
- surface area
- concentration gradient
- membrane permeability
- membrane thickness

you do top 3 x together then divided by membrane thickness (think like need a thick base)

Feedback control & physiology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions