Hormonal Regulation of Kidney Function Flashcards
How is renin secretion controlled?
Decreased PB stimulates intrarenal baroreceptors
Decreased deliver of NaCl and Tubular fluid volume to the DT macula densa cells causes systemic release of renin
Increased sympathetics
Ang II INHIBITS
Where is Ang II located and how is its release controlled?
Ang II circulates in the systemic circulation and can be produced intrarenally
Activated by ACE in the lung (AI –> AII)
Concentration of A II is directly related to the level of renin in the systemic circulation
What are the actions of Ang II?
Direct stimulation of Na reabsorption in the PT
Indirect stimulation aldosterone
Stimulates release of ADH
Vasoconstriction (vasopressin)
Where are prostoglandins produced?
Glomerular and vascular endothelium
Collecting tubule cells - main synthesis site
Renomedullary cells
Synthesis increased by by vasoconstrictors
What is the action of prostaglandins?
Local intrarenal vasodilation
Counteract effect of renal vasoconstriction, minimizes the extent of renal ischemia
Infusion promotes natriuresis and iuresis
Where is bradykinin produced and what are its functions?
Produced by kidney cells
Vasodilation, natriuresis, diuresis
Where is ADH produced and how is its release controlled?
Surpraoptic and paraventricular nucleus of the hypothalamus
Controlled by increased hyperosmolality and depletion of effective circulating volume
What are the actions of ADH?
Stimulation of V2 receptors on principal cells - increased number of luminal water channels, increasing ECF
Stimulation of V1 receptors on renal and systemic vasculature - vasoconstriction
What is syndrome of inappropriate ADH secretion?
Surgical patients have a persistent rise in ADH due to stress/pain response, can lead to water retention with hyponatremia
What is diabetes insipidus?
Disorder characterized by intense thirst and by the excretion of large amounts of diluted urine
Central - characterized by decreased secretion of ADH
Nephrogenic - decrease in the ability to concentrate urine do to ADH resistance in the kidney
Where is aldosterone produced and how is its release controlled?
Produced in the zona glomerulosa of the adrenal cortex
Primary regualtion is by increased AG II
What are the actions of aldosterone?
Increased Na and Cl reabsoprtion
Increased K and H secretion
What is aldosterone escape?
Prolonged treatment with aldosterone results in brief period of salt retention, but only lasts a few days
Escape due to rise in ECF volume which effectively decreases Na reabsorption in PT
Where is ANP produced and how is it controlled?
Produced in right atrial myocytes and released by increased atrial stretch due to hypervolemia
What are the renal functions of ANP?
Inhibits Na reabsorption in PT and CD
Inhibits ADH dependent water reabsorption
Hyperfiltration - vasodilation of preglomerular arteries
Inhibits renin release
