Long-term Control of Blood Pressure Flashcards
What is key in regulating mean arterial pressure?
Controlling plasma volume
What are the functions of the kidneys?
Excretion of waste products Maintenance of ion balance Regulation of pH Regulation of osmolarity Regulation of plasma volume
In the kidney how is a very high osmolarity created outside the collecting duct?
By the renal counter-current system
What determines the osmotic gradient?
Control over sodium ion transport
What determines if water follows the osmotic gradient?
Control over the permeability of the collecting duct
How is plasma volume conserved?
By making the collecting duct very permeable resulting in a lot of water reabsorption
How is plasma volume reduced?
By making the collecting duct very impermeable resulting in little reabsorption of water
What are the 3 hormone systems that regulate the process of plasma volume regulation?
Renin-angiotensin-aldosterone system
Antidiuretic hormone
Atrial natriuretic factor and brain natriuretic factor
Where is renin produced?
From the juxtaglomerular of the kidney
What triggers renin production?
Activation of sympathetic nerves to the juxtaglomerular apparatus
Decreased distension of afferent arterioles (the “renal baroreflex”)
Decreased delivery of Na+/Cl- through the tubule
What does release of renin indicate?
Low mean arterial pressure
What does renin do?
Converts inactive angiotensinogen to angiotensin I, which is turned into angiotensin II by angiotensin converting enzyme
What does angiotensin II do?
Stimulates release of aldosterone from the adrenal cortex
Increases release of antidiuretic hormone (ADH) from the pituitary
Is a vasoconstrictor
What is the total effect of angiotensin II on the body?
Increases mean arterial pressure
Where is ADH produced?
Synthesised in the hypothalamus and released from the posterior pituitary gland
