Flashcards in BP Regulation- T2 Deck (34):
3 methods of short term BP regulation
change in vessel diameter and changes in HR and contractility and baroreceptor control
largest systemic pressure drop occurs in the ___ and why is it significant
occurs in the arteriolar beds thus this is the region with the greatest resistance to blood flow
changing ___ diameter in these vessels will also influence the ____
lumen, systemic BP
thick later of muscular tunica media in ___ and ___ allows for rapid change in vessel ___ diameter in response to __ or __
thick later of muscular tunica media in arteries and arterioles allows for rapid change in vessel lumen diameter in response to sympathetic nerve stimulation or hormones
cardiovascular centers in the medulla oblongata initiate tonic sympathetic discharge that is transmitted down the spinal cord, via the ___ and ___ to the ___
presynaptic fibers, chain ganglia, vasculature.
the release of NE within the wall of arteries is responsible for:
activating alpha1 adrenoreceptors to cause vasoconstriction
most arteries and veins receive nerve inputs from ____
postganglionic sympathetic neurons. with arteries and arterioles being more densely innervated
epi and some NE released from _____ during sympathetic activation is though to activate ____ which is more densely localized on the ___
adrenal medulla. alpha2 adrenoceptor. lumens side of the smooth muscle layer.
tissue metabolites (___, ___) and increasing ___ (decreasing __) can cause vasodilation of arterioles and ___ to increase tissue blood flow
(lactic acid, prostaglandins). increasing PCO2 (decreasing PO2). arterioles and venules
TPR * CO
TPR is influenced by
CO is influenced by
HR * SV
SV is related to ___ therefore increasing___
related to myocardial contractility therefore increasing contractile force of the heart increased SV
both SV and HR influence the amount of
blood the heart delivers per cardiac cycle to circulatory system (CO)
___ directly increase the rate and ___ of the heart to influence the ___ of the heart
beta-adrenoceptor agonists. contractility. CO.
baroreceptors are ___ found in the ___ and detect____
around stretch receptors found in the walls of the carotid sinus and the aortic arch that detect changes in the arteria pressure.
increase in BP causes distention of the baroreceptors leading to ____
increased rate of firing of afferent sensory nerves that eventually inhibit the tonic firing of the sympathetic motor center in the medulla.
the baroreceptor reflex is concerned with
the maintenance of the mean blood pressure.
drugs that cause increase in MBP initiate the reflex to
bring down the pressure
why does HR decrease with phenylephrine administration
it causes an increase in BP, which activated baroreceptors to try and decrease it by lowering the HR
long term BP regulation is achieved by the
regulation of blood volume by the kidneys.
Describe the renin-angiotensin-aldosterone axis for volume regulation
changes in blood volume due to sustained blood loss are decide by the macula densa cells of the kidneys as a decrease in Na in the glomerular filtrate. Renin is released in response to the sodium load. Macula dense cells communicate to the juxtuglomerular cells to release renin the conversion of angiotensnogen to angiotensin I to angiotensin II
juxtaglomerular cells of the kidney are stimulated to release __
renin into the blood which converts angiotensinogen to angiotensin I
angiotensin I is converted to II by __ found on __ cells
angiotensin-converting enzyme (ACE) found on endothelial cells.
angiotensin II is a potent___. Also releases __
vasoconstrictor that helps maintain the falling BP. Also releases aldosterone from the adrenal cortex, which causes increased Na and water reabsorption from the distal convoluted and collecting tubules.
what receptors on JG cells are innervated and increase renin release
how is angiotensin II a multifunctional hormone
enhance sympathetic output at nerve ending and increase norepi release
Increases in blood __ are detected by
osmolarity are decide by the pituitary to cause release of ADH into the blood
ADH is a __ that helps maintain ___
water reabsorption in the DCT and collecting ducts of the kidneys.
ADH stimulated the ___
thirst centers of the hypothalamus to increase water intake.
less than ___% of HTN cases have any identifiable causes (secondary HTN): 5 examples.
15%. aortic coarctation, renal artery constriction, cushings syndrome, pheochromocytoma, primary aldosteronism.