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प्रश्न
Prove that mammalian urine contains urea.
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उत्तर
- Urea is a nitrogenous waste formed by breakdown of protein (deamination of amino acids).
- During this process, amino groups are removed from the amino acids present in the proteins and converted to highly toxic ammonia. The ammonia is finally converted to area through ornithine cycle. Thus, the urea formed is passed to kidneys and excreted out of the body through urine.
- Reabsorption of urea (proximal tubule, collecting ducts) and active secretion of urea (Henle loop) leads to a urea circulation (urea recycling) between the lumen of the nephron and renal medulla, which is an important element of the renal urine concentration.
- About 54 g of urea is filtered per day in the glomerular capsule, of which approximately 30 g is excreted in the urine and 24 g is reabsorbed into blood (assuming GFR is 180 litres/day).
- Urinalysis can help detect the amount of urea in urine (Urine urea nitrogen test, urease test, etc.).
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संबंधित प्रश्न
Osmoreceptors involved in renal control mechanism are found in ____________ part of the brain.
The first step of urine formation takes place in the ______.
Diuresis means ______.
The causes of the formation of uric acid stones are decreased intake of water and ______
Juxtaglomerular cells are activated to release renin by ______
Diabetes insipidus is caused due to ____________.
The ascending limb of the loop of Henle's is lined by ______.
Blood pressure is regulated in kidney.
The correct sequence of these steps is
i. Formation of Angiotensin II
ii. Secretion of Aldosterone
iii. Fall in blood pressure
iv. Reabsorption of Na+ from distal convoluted tubule.
v. Release of Renin
vi. Restoration of normal blood pressure
vii. Conversion of Angiotensinogen to Angiotensin I
viii. Activation of Juxta Glomerular cells.
Identify the INCORRECT statement.
Renin and angiotensin are secreted by ______ and ______ respectively.
