Enzymatic control of blood pressure Flashcards
What sounds can be heard using a stethoscope and sphygmomanometer?
Korotkoff sounds
What is interstitial fluid volume?
The fluid that bathes the cells
What are the 2 main factors that affect extracellular fluid volume?
Water excess or deficit
Na+ excess or deficit
Which enzymes are involved in the RAAS?
Renin
Angiotensin
Aldosterone
What is an NP?
Natriuretic peptides
What is ADH?
Antidiuretic hormone (aka Arginine vasopressin)
What occurs in the RAAS?
Renin released from the kidneys
Stimulates conversion from angiotensinogen to angiotensin I in the liver
ACE converts angiotensin I to angiotensin II
Angiotensin stimulates the release of aldosterone from the adrenal cortex
What does ACE stand for?
Angiotensin Converting Enzyme
Where is ACE mainly produced?
By the pulmonary vascular endothelium, in the lungs
What are the functions of angiotensin II?
Stimulates thirst
Stimulates ADH release
Causes systemic vasoconstriction
What is the function of aldosterone?
It acts on the kidneys to increase retention of sodium and water
Which cells in the kidneys secrete renin?
Granular cells of the juxtaglomerular apparatus
What forms the juxtaglomerular apparatus?
The macula densa (In the kidney tubule lining)
The extraglomerular mesangial cells
The granular cells in the afferent arteriole wall
What is the function of the macula densa?
It monitors and detects Na+ level in the renal fluid
What are 3 factors that can stimulate the release of renin?
Renal artery hypotension
Decreased [Na+] in renal fluid
Stimulation of renal sympathetic nerves
Where are natriuretic peptide hormones synthesised?
In the heart, brain and some other organs
What stimulates the release of natriuretic peptides?
Cardiac distension or neurohormonal stimuli
What is the function of natriuretic peptides?
They cause the excretion of salt and water in the kidneys, thus reducing blood volume and so pressure
The also decrease renin release
They also act as vasodilators
