Hormones acting on the Kidney Flashcards
Which hormone regulates sodium reabsorption in the kidneys?
Aldosterone.
How does aldosterone affect kidney function?
Aldosterone increases sodium reabsorption and potassium excretion in the distal tubules and collecting ducts.
What triggers the release of aldosterone?
Decreased blood pressure, increased potassium levels, and activation of the renin-angiotensin-aldosterone system (RAAS).
What is the role of antidiuretic hormone (ADH) in the kidneys?
ADH increases water reabsorption in the kidneys, reducing urine volume.
How does ADH influence water reabsorption?
ADH increases the permeability of the collecting ducts to water, allowing more water to be reabsorbed.
Where is ADH produced and released?
ADH is produced in the hypothalamus and released from the posterior pituitary gland.
What stimulates the release of ADH?
Increased plasma osmolality and decreased blood volume stimulate ADH release.
What is the function of atrial natriuretic peptide (ANP) in the kidneys?
ANP promotes the excretion of sodium and water, reducing blood volume and pressure.
How does ANP affect sodium and water excretion?
ANP increases glomerular filtration rate (GFR) and decreases sodium reabsorption in the distal tubules and collecting ducts.
What conditions stimulate the release of ANP?
Increased blood volume and atrial stretch stimulate ANP release.
How does parathyroid hormone (PTH) act on the kidneys?
PTH regulates calcium and phosphate reabsorption in the kidneys.
What is the effect of PTH on calcium and phosphate reabsorption in the kidneys?
PTH increases calcium reabsorption and decreases phosphate reabsorption in the proximal and distal tubules.
Where is renin produced and what is its role in kidney function?
Renin is produced by juxtaglomerular cells and initiates the RAAS to regulate blood pressure and fluid balance.
How does renin contribute to the regulation of blood pressure?
Renin converts angiotensinogen to angiotensin I, leading to the production of angiotensin II, which increases blood pressure.
What triggers the release of renin from the kidneys?
Decreased renal perfusion, sympathetic nervous system activation, and low sodium chloride concentration in the distal tubule.
What is the function of angiotensin II in the kidneys?
Angiotensin II constricts efferent arterioles, increasing glomerular pressure and GFR.
How does angiotensin II affect glomerular filtration rate (GFR)?
It increases GFR by constricting the efferent arterioles more than the afferent arterioles.
What is the effect of aldosterone on potassium levels in the kidneys?
Aldosterone promotes the excretion of potassium in the distal tubules and collecting ducts.
How does insulin influence renal glucose handling?
Insulin increases renal glucose reabsorption in the proximal tubules.
What is the role of calcitriol in kidney function?
Calcitriol, the active form of vitamin D, increases calcium reabsorption in the kidneys.
How does erythropoietin (EPO) affect the kidneys?
EPO stimulates red blood cell production and can affect renal oxygen sensing and function.
Where is erythropoietin produced and what stimulates its release?
EPO is produced by the peritubular fibroblasts in the renal cortex, stimulated by hypoxia.
How do catecholamines (epinephrine and norepinephrine) affect kidney function?
Catecholamines constrict renal blood vessels, reducing renal blood flow and sodium excretion.
What is the effect of prostaglandins on the kidneys?
Prostaglandins act as vasodilators, increasing renal blood flow and promoting sodium excretion.
