atrial and pulmonary stretch receptors Flashcards
where are stretch receptors?
atria
pulmonary arteries
pulmonary veins
right atrium
superior and inferior vena cava
which receptors respond to lower pressures?
cardiopulmonary stretch receptors
role of cardiopulmonary stretch receptors?
regulate blood volume (which in turn regulates cardiac output and then blood pressure)
effect of a drop in venous blood pressure on atrial pressure
atrial pressure decreases
what happens to the stimulation of cardiopulmonary stretch receptors when atrial blood pressure falls?
decreased stimulation
what is the relationship between ADH and cardiopulmonary stretch receptors?
a decrease in cardiopulmonary stretch receptor stimulation causes ADH release
where is ADH released?
hypothalamus
what is the effect of ADH?
fluid from renal tubules is reabsorbed
what causes the afferent renal arterioles to constrict?
a reflex triggered by a drop in cardiopulmonary stimulation
what is the effect of vasoconstriction of afferent renal arterioles?
glomerular filtration rate is reduced
how doe ADH and a reduction in glomerular filtration rate act to increase blood volume?
reduce fluid loss to the urine
how does ADH increase total peripheral resistance?
vasoconstriction
what is the set point for MAP?
100mmHG
when barroreceptors are denervated, what happens to the MAP
the peak remains the same but there is a larger range
what happens to the peak arterial pressure when baroreceptors and cardiopulmonary receptors are denervated?
peak MAP increases
larger range
where are chemoreceptors?
carotid and aortic bodies
which metabolites are chemoreceptors sensitive to?
oxygen carbon dioxide and hydrogen ions
what roles do chemoreceptors have
respiratory and cardiovascular regulation
which states stimulate chemoreceptors?
hypoxia hypercapnia and acidosis
what process do chemoreceptors stimulate?
sympathetically-mediated peripheral vasoconstriction
what effect does chemoreceptor simulation have on heart rate and depth of breathing?
increase
what does the lung inflation reflex trigger?
increase in heart rate and small vasodilation
how does chemoreceptor simulation lead to an increase in MAP?
increasing cardiac output and TPR
what pathologies are chemoreceptors particularly important in?
asphyxia or major haemorrhage
what kind of effect do neural reflexes have on MAP?
short time
describe the lasting effect of blood volume in determining arterial pressure
long term
which organ is involved in blood volume regulation
kidney
a small increase in renal arterial pressure has what effect on urine output and glomerular filtration?
large increase
which system controls the relationship between arterial pressure and urine output?
renin-angiotensin-aldosterone system
what stimulates the renin-angiotensin-aldosterone system
decrease in blood volume or renal blood flow
what does the kidney release in response to drop in blood pressure?
renin
renin converts angiotensinogen into what?
angiotensin 1
what is the role of ACE?
converts angiotensin 1 into angiotensin 2
what is the effect of angiotensin 2?
increases thirst and vasoconstriction
aldosterone release
where is aldosterone released
kidney
how does aldosteorne increase blood pressure
increases salt and water retention therefore more water is absorbed
what drugs are used to treat hypertension?
ACE inhibitors
vasoconstriction has what effect on TPR?
increases
what effect does increase in blood volume have on cardiac output?
increases
how does adrenaline increase cardiac output?
through increasing stroke volume and heart rate
effect of sympathetic innervation from preganglionic fibres?
adrenaline and noradrenaline release
which receptors mediate the effect of adrenaline?
beta adrenoreceptors
adrenaline targets of action:
SAN
ventricular muscle
how does noradrenaline increase
raising TPR via vasoconstriction via alpha adrenoreceptors
what is the effect of ANP on MAP?
decrease
how does ANP decrease MAP?
vasodilation and increasing excretion of sodium in the kidneys
describe the release of ANP
atrial cells release ANP when cardiac filling pressures are high
why does NO have little effect on MAP?
acts locally
