Control of blood pressure Flashcards
Where is the baroreceptor reflex present?
Carotid sinus and aortic arch
What nerve does the baroreceptor send signals down on the aortic arch and carotid sinus
Aortic arch- Vagus nerve
Carotid sinus- Glossopharyngeal nerve
Describe what the baroreceptor causes with an increase in bp
more action potentials fire down the glossopharyngeal nerve (From carotid sinus) and vagus nerve (From aortic arch).
Fire to the medulla oblongata in the brain that causes a negative effect on the sympathetic NS
Decreases heart rate and causes vasodilation
Describe what happens when there is a decrease in blood pressure
With decreased blood pressure, the baroreceptors fire less to the medulla oblongata, increasing sympathetic and decreasing parasympathetic output.
Increases the heart rate, inotropy and increases total peripheral resisstnace
What four pathways control blood pressure
RAAS
Sympathetic nervous system
ADH
Natriuetic peptides
Name three factors that stimulate renin release
Reduced NaCl delivery to distal tubule
Reduced perfusion prssure in kidney
Sympathetic stimulation to the juxtaglomerular appartus
What type of cells in the kidney release renin
Juxtaglomelular Granular cells
Describe the RAAS process
Renin released from kidney Juxtaglomelular granular cells in response to stimulus
Liver releases angiotensinogen
Renin converts angiotensinogen–>Angiotensin 1
Angiotensin 1, triggers the release of ACE from the lungs
ACE coverts angiotensin 1 into angiotensin 2
Name the two angiotensin 2 receptors. Name the five sites where the angiotensin 2 receptors are found. Name the effect it has at each of these sites
Arterioles- Vasoconstriction
Kidney- Increased Na+ re-absorption
Sympathetic nervous system- Stimulates it
Adrenal cortex- Causes release of aldosterone–> Increased Na+ reabsorption
Hypothalamus- Increases thirst sensation and stimulates ADH release
How does aldosterone work at the kidney
Activates the apical Na+ cells in tubule
Increases Na+ uptake by epithelial cells
Na+ leaves the cells and enters the bloodsteam via the Na+/K+ ATPase pump at the basolateral side of the cells
Describe the effect of the sympathetic nervous system on the kidneys
Reduces renal blood flow via vasoconstriction
Activates apical Na+/H+ exchanger in the proximal convoluted tubule–>Na+ reabsorption
Activates basolateral Naa+/K+ ATPase
stimulates release of Renin from juxtaglomerular granular cells
Where is ADH released from?
Hypothalamus
What effect does ADH have
reduces water loss in urine by concentrating it
Also causes a bit of vasoconstiction
What are the two natriuretic peptides.
What causes their release?
ANP and BNP
Released when atria and ventricles are stretched indicating high blood pressure
What do the natriuretic peptides cause? How?
Promotes Na+ excretion
Vasodilations afferent arterioles–>More blood flow to kidneys–>Decreased Na+ reabsorption
