Kidney As An Endocrine Organ Flashcards
What is erythropoietin produced in response to
Hypoxia
What does erythropoietin promote
Red blood cell production in the bone marrow
How does erythropoietin work
Binds to receptors on RBC progenitors promotes proliferation, differentiation and survival of the progenitor cells
What does calcitriol/vitamin D3 do in the kidneys
Increases Ca absorbed in the GI tract
Promotes reabsorption of Ca in the kidneys
Stimulates Ca release from bone
What is calcitriol
The active metabolite of vitamin D3 and is a steroid hormone
How does calcitriol work
Binds to receptors which increases transcription of a gene encoding Ca binding protein allowing more Ca to be transported from the intestines into the blood
Where is calcitonin found
In the thyroid released when Ca in the plasma is high to reduce it
What does calcitonin do
To prevent Ca loss from the skeleton
Why would the parathyroid hormone be released
In response to low plasma Ca levels increasing availability of Ca
Works with calcitriol
What is renin secreted by
Cells in the juxtaglomerular apparatus in kidney
What does renin hydrolyses
Angiotensinogen to angiotensin I
What does renin do
Regulates blood pressure by regulating fluid balance
Released as a result of low blood pressure in afferent arterioles
Cleaves angiotensinogen to release angiotensin I further cleaved to produce angiotensin II
What does angiotensin II cause
Vasoconstriction of vessels
More constriction of glomerular efferent than afferent arterioles to maintain GFR
What does angiotensin II stimulate the release of
Aldosterone from the adrenal cortex which increase reabsorption of Na and water in the nephron
What does ADH cause
Water reabsorption from the nephron stimulates thirst
What do ACE inhibitors do
Stop the conversion of angiotensin I to angiotensin II so lower blood pressure
What does atrial natriuretic peptide do
Made and released by muscle cells in heart as a response to increased blood pressure
Causes increased Na excretion and increased water loss in urine
How is the kidney an endocrine organ
The adrenal glands on top of the kidneys release hormones
What are the 2 main groups of steroid hormones
Corticosteroids
Sex steroids
what do steroid hormones do
Lipid soluble which act inside cells to change transcription of DNA changing the proteins expressed
What are 3 steroid hormones
Mineralcorticoids
Glucocorticoids
Androgens
Which 2 hormones regulate mineral balance
Mineralcorticoids
Glucocorticoids
Where is catecholamines produced
From adrenal medulla
What does catecholamines do
Mediate fight or flight
(Adrenaline and noradrenaline)
What can tumours in the kidney result in
Over secretion of renin leading to high blood pressure
What is anaemia
Common in people with CKD as they don’t produce enough erythropoietin fewer red blood cells
What is hypoaldosteronism
Decreased aldosterone levels
What can congenital adrenal hyperplasia do
Can result in late or early puberty, ambiguous genitalia or infertility
