Long-term Regulation of Arterial Pressure Flashcards
How is blood pressure regulated long term?
By regulating blood volume
Why is blood volume a major determinant of arterial pressure?
Influences: venous pressure, venous return, end-diastolic volume, stroke volume and cardiac output
How are arterial blood pressure and blood volume related?
Increased blood volume = increased arterial pressure
Increased arterial pressure = decreased blood volume
What factors effect blood volume and what controls these factors?
Changes in sodium ion and water concentration effect blood volume and this is controlled by the kidneys
What is the normal value of plasma osmolarity?
-290 mosmol/kg
What is plasma osmolarity sensed by?
Hypothalamic osmoreceptors
What is the other name for ADH?
Vasopressin
How does a decrease in blood pressure effect plasma osmolarity?
Blood osmolarity increases
How does an increase in plasma osmolarity effect renin production?
Renin production increases
What does renin do?
It cleaves angiotensinogen to form angiotensin I
How is angiotensin I converted to angiotensin II?
By the enzyme angiotensin-converting enzyme (ACE)
Where is angiotensin II primarily produced?
The lungs
What effect does angiotensin II have on water retention and how does this effect blood volume?
Angiotensin II promotes water retention in the kidneys. And increases sodium and chloride ion reabsorption. Water follows solutes by osmosis so water is reabsorbed, increasing blood volume
Increased levels of angiotensin II, increases the secretion of what molecule?
Aldosterone
Where is aldosterone released from?
The adrenal cortex
What effect does aldosterone have on blood volume and how does it achieve this effect?
Aldosterone increases sodium and chloride ion reabsorption and increases potassium ion secretion by altering the activity of the Na/K-ATPase. This promotes water retention and increases blood volume
Where is ADH released from?
The posterior pituitary gland
What effect does ADH have on blood volume and how does it produce this effect?
ADH increases water permeability of principle cells in the collecting ducts of the kidney by recruiting aquaporin-2 water channels to the surface of these cells. More water is reabsorbed and blood volume increases
What effect does ANP have on blood volume and how does it achieve this effect?
It decreases blood volume by increasing water loss by increasing glomerular filtration rate and inhibiting the secretion of aldosterone and ADH.
Where is renin released from?
Juxtaglomerular cells in the kidney
What is ADH secretion stimulated by?
Angiotensin II
Increase in blood plasma detected by hypothalamus osmoreceptors
