CM - Hormones that Act on the Kidney

antidiuretic hormone (ADH)

-AKA vasopressin -a hormone of the posterior pituitary -the hypothalamus senses the osmolarity of body fluids and secretes or withholds this hormone

aldosterone

-a "salt-retaining" hormone -its secretion results in moving Na+ from the interior of the tubules back into the body -conserves Na+ and eliminates K+ -water will follow, which will increase blood volume -produced and stored by the adrenal gland under direction from the pituitary gland -controlled by the RAAS

angiotensin II

-active vasoconstrictor -stimulates aldosterone secretion -directly stimulates Na+ reabsorption from proximal tubules -constricts efferent arterioles (increased reabsorptive forces for Na+ and H20 at peritubular capillaries) -secretion results in vasoconstriction of systemic vascular beds (a potential cause of chronic systemic hypertension) -increases systemic vascular resistance, which increases arterial pressure

hormones that act on the kidney

-renin -aldosterone -angiotensin II -antidiuretic hormone -atrial natriuretic peptide -parathyroid hormone

atrial natriuretic peptide

-secreted by cardiac atrial cells if there is distention/stretch of atria (too much preload) -inhibits reabsorption of Na+, H20 -opposes the action of aldosterone

parathyroid hormone

-secreted by the parathyroid gland in response to low serum Ca++ -increases renal Ca++ reabsorption (reclaims Ca++) -decreases renal phosphate reabsorption (ditches phosphorus)

If increased osmolarity is sensed by the hypothalamus...

...ADH is secreted from the pituitary, resulting in increased reabsorption of H20 by the kidney, producing concentrated urine.

If serum/ECF osmolarity is low...

...ADH is withheld by the pituitary and the kidney removes water, producing dilute urine.

If phosphorus levels increase...

...levels of free, active calcium will decrease.

If calcium is serum is low...

...one will pee off phosphorus and hang onto calcium to raise the levels of free, active calcium.

If calcium and phosphorus are bound together...

...they are inactive.

diabetes insipidus

Pathophysiology a syndrome of inappropriate ADH secretion

renin-angiotensin-aldosterone system (RAAS)

a coordinated system of hormones that regulate the body's blood pressure and water balance in the kidneys

renin

a hormone that is produced and released by the the juxtaglomerular cells of the kidney

What can cause chronic systemic hypertension?

secretion of angiotensin II that vasoconstricts the systemic vascular beds