Questions tagged [kidney]

The kidney is an internal, bean shaped organ of vertebrates. Kidneys are responsible for secreting urine, regulate the electrolytes of the body and filter the blood.

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Why is the afferent arteriole considered to be the last branch of the kidney artery

Why is the afferent arteriole considered to be the last branch of the kidney artery while the efferent arterial is also present and branches off on its own again?
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Why is urine acidic (equilibrium of I/O, input <=> output)

Urine pH is on average 6.0, net excretion of acid. Is that in balance with net input of acid?
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Kidney: Is added resistance on proximal tubules a function of the narrowness of the descending limb?

The efferent arteriole has a smaller diameter than the afferent arteriole. This forces the part of the blood that is able to leave the blood vessels of the glomeruli (excludes large bodies like blood ...
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Why does number of nephrons increase exponentially in kidney evolution?

The number of nephrons is often depicted to be increasing exponentially in kidney evolution. What is the primary reason for that increase?
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Water used in excretion in ureotelism vs ammonotelism

Ureotelism is an adaptation to conserve water, less water is needed to excrete nitrogen compared to in ammonotelism. Is the water usage more or less exactly proportional to the number of nitrogen ...
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Why is glomerular filtration called a non selective process?

According to Biology NCERT Class 11, Page 299, "Filtration is a non-selective process performed by the glomerulus using the glomerular capillary blood pressure." But the glomerulus filters out blood ...
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Why does glomerulus don't allow white blood cells to leave?

The glomerulus in nephrons are just a ball of capillaries, so why can't it allow the white blood cells to squeeze though the epithelial cells into Bowman's capsule just like the formation of tissue ...
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How does the descending branch of the loop of Henle equilibrate concentration?

I'm learning physiology and I have a hard time figuring out how the cortico-papillary gradient is created. Most explanations go as follow: 1) Sodium is pumped out the ascending branch into the ...
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Vasoconstriction and blood flow

The resistance in a blood vessel is equal to the pressure difference divided by the blood flow. Let us now say that a sympathomimetic causes vasoconstriction which increases the resistance. Does this ...
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Why is urea not converted to ammonia in the body?

After the liver processes metabolites to produce urea and other by-products, these travel in the blood to the heart, then they are oxygenated, and some travel through the renal artery to the kidneys. ...
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Creatinine excretion

Creatinine accumulates in blood if kidneys fail to excrete it. Does this unexcreted creatinine ever get thrown out of body? What prevents creatinine from continuously rising in the blood?
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Why is erythropoietin produced in the kidney?

Erythropoietin is a hormone produced in the kidney to stimulate the generation of more red blood cell. It is triggered by low oxygen via HIF transcription factors. Makes sense. Oops, oxygen is low, ...
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Hematuria due to Nitric Oxide

Drug interactions between properly dosed NO and other medications are not expected, but side effects may include noisy breathing, hematuria, or possibly atelectasis. (pg.no:577; Goodman and Gilman ...
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334 views

Polar renal scarring in pyelonephritis?

Why does infection and scarring occurs at poles in Vesicoureteric reflux but not in Obstructive pyelonephritis? It is said in Robbins that, it is due to polar papillae being flattened or concave ...
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Acidity and Alkalinity of Foods

Some foods leave an acidic effect on the body such as meat and dairy, while others leave an alkaline effect, like vegetables. However, are these effects significant enough to greatly alter the blood ...
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How increased potassium intake increases sodium excretion?

"K+ antagonises the biological effects of Na+". I have been reading the same many times without any explanation. How actually (mechanism) K+ helps excretion of Na+?, their interactions? And eventually ...
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Do fruit juices have a diuretic effect & what governs this?

Was just contemplating this. Juices tend to contain a lot of sugar. Does the body absorb all the sugar in juices? If the body does not, that sugar must be excreted by the kidneys alongside water ...
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Is the glomerular filtration rate, per kidney or for both?

We say in a healthy human being the average glomerular filtration rate is about 120 mL/min. Is that for both kidneys together (60+60), or just one kidney? Pardon me if this makes me sound like an ...
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What does it mean for sodium and water reabsorption to be “coupled” in the nephron?

If sodium is transported across the tubule membrane down the concentration gradient established via the $Na^+$/$K^+$ exchanger via symport with glucose and antiport with hydrogen, and water is ...
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Can polystyrene sulfonate bind calcium or sodium in the gut? How?

Polystyrene sulfonate is used as a potassium binder to treat hyperkalemia in traumatic rhabdomyolysis, acute and chronic kidney disease. It is listed as an ion-exchange resin that can also remove ...
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How might IV-saline cause kidney damage that seems to be less likely with “balanced fluids” IVs instead?

The ABC News article What's in the IV bag? Studies show safer option than saline includes: Saline — salt dissolved in water — has been the most widely used fluid in the U.S. for more than a century ...
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Is there a way to remove hemoglobin from pig kidney homogenate without deactivating enzymes?

I would like to measure different enzyme activities in centrifuged pig kidney homogenate. I get out of range errors at 450 nm. The samples are still reddish after centrifugation. Is there a way to ...
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How does the counter-current multiplier work in the nephrons?

Why is the counter-current multiplier called like that? What is flowing in the opposite direction to the glomerular filtrate for it to be called "counter-current"? Can you please explain the counter-...
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Kidney transplant and adrenal glands

When a kidney is transplanted from a donor to a recepient does the surgery occur keeping the donor's adrenal gland intact over the kidney or is the kidney minus the adrenal gland over it transplanted ...
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Does cortical nephron has just thin ascending loop of Henle?

Guyton and Hall , South Asian edition states that, in Table 76-1 that ascending limb of loop of Henle has thin segment only. But, none diagram in book or internet explain this. Can any one explain ...
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679 views

Why are ammonium ions reabsorbed in the thick ascending limb during acid secretion?

In order to produce HCO3- from glutamine and to subsequently reabsorb it, H+ ions need to be secreted. The kidney does this by via ammonium ions in the PCT. But why are the ammonium ions then ...
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Excess protein consumption effect on kidney

How does excess protein consumption through food as well as through supplements affect body especially kidneys? Why it is advice to consume low protein diet during summer ?
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What is meant by re-absorption?

It is said that PCT, DCT, Henle’s Loop reabsorb the filtrate. Does that mean they absorb the filtrate again? If it is actually reabsorbed to medulla then why it is said that PCT, DCT or Henle’s loop ...
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Is excess of potassium as strenuous and harmful for kidneys as excess of sodium or worst?

I was wondering since channels of body's cell membranes deal with potassium and sodium ions differently and considering the fact that potassium lowers blood pressure and sodium raises it : What is ...
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Portal Systems in Humans

I was reading about nephrons in my physiology book when i came across this- The efferent arterioles and peritubular capillaries technically constitute a portal system But according to Wikipedia, ...
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Does sodium lower the harmful effect of potassium on kidneys?

As far as I have read so far, it seems that potassium and sodium are trying to expel each other from the human body. A lot of documents on the web say too much sodium pressures the kidneys could cause ...
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Is Valerian extract a diuretic or an antidiuretic?

I am trying to determine if valepotriates (valerian extract) is a diuretic or an antidiuretic. Some individuals take valerian as an herbal supplement for anxiety disorders. Some individuals claim that ...
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What is the evidence that mammals are unable to process excess sodium chloride?

I grew up hearing the mantra excess salt causes heart disease I had a vague understanding that it caused deposits in the body or something. Now that I give it more thought - I come up with three ...
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peritoneal dialysis Vs Hemodialysis?

Their are basically two types of dialysis: 1.peritoneal dialysis 2.hemodialysis, My Question is Why the peritoneal dialysis needs to be carried out on everyday BUT hemodialysis is carried out on only ...
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Diabetes Mellitus and renal failure?

I have studied that Diabetes Mellitus leads to kidney failure and that this is because of the damage to the blood vessels (especially the blood vessels in the kidney) due to high levels of blood ...
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Function of human kidneys

Why are the kidneys called metanephric? What does the term metanephric actually mean? I tried to search that on Google but couldn't find the exact meaning.
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What is the function of the kidney in terms of osmoregulation and excretion [closed]

Also include the role that ADH plays I am fully aware that ADH has a role in osmoregulation but does it also play a role in exretion?
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Find how much times blood is filtered in the kidney? [closed]

The blood that circulates in our body is about 1/12 of our mass. If the kidneys filter 7.5 liter of blood a hour, then how many times does it filter in the kidney the whole blood of a person will mass ...
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How do cellular waste products enter arterial blood?

I recently learned that blood in renal arteries contains waste materials, which is filtered via nephrons in the kidneys. My question is, how are these waste materials getting into the arterial blood?...
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Why does the kidney of a cow have lobules, why the kidney of a human hasn't any?

The kidney of a cow has lobules, while the kidney of a human hasn't any. I can't think of any reason why it would be good for a kidney to have lobules. It would be good if the kidney needed to have a ...
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Is the PCT of the nephrons of the kidneys of marine vertebrates to minimize the natural tendency for exosmosis?

For marine vertebrates, the concentration of salts outside their body (in the water, that is) is more than that inside their body. So, there is a natural tendency for exosmosis to occur. To minimise ...
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How does ANF increase GFR?

ANF as we know reduce the Na+ uptake and K+ removal in the distal tubules and it also functions as a Vasodialator (?) But again it says that ANF increases the Glomerular filtrate ? But if it is acting ...
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Why is heart failure treated as more critical than kidney failure?

The heart pumps the blood to supply tissues and kidney always filters the blood to remove urea,extra water and etc. And all these are vital,so the kidney is as important as heart: and my question is: ...
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How do kidney cells excrete their own wastes?

The kidney is composed of tissues, and those tissues are made up of numerous cells - so how do these cells excrete their wastes? Lastly, are there any wastes in the venous blood (renal vein), what ...
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What is refractory proteinuria?

I've stumbled upon the article "Telmisartan Treatment of Refractory Proteinuria in a Dog."* What is refractory proteinuria? *Bugbee AC1, Coleman AE, Wang A, Woolcock AD, Brown SA. J Vet Intern Med. ...
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For how long can a person drink sea water?

How long could a person of lets say 18 years be able to drink sea water without getting too much into trouble ? Or can a person drink it without noticing that it is a very bad idea ? I don't mean in ...
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What is the reason behind more severe proteinuria in nephrotic syndrome than in nephritic syndrome?

Why is there less protein loss via urine in case of nephritic syndrome than in case of nephrotic syndrome?
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Can tubular secretion regarded as local hormone?

Tubular secretion is : The process in which ions and other waste products are transported into the distal tubules of the nephron. can it be regarded as local hormone??
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How does the counter current mechanism concentrate urine?

The movement of ions like sodium into the interstitial space causes water to passively diffuse out the descending loop of Henle. How does this concentrate the urine? The solvent is removed at one ...
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To diagnose osteomyelitis of vertebral column in chronic kidney failure

Assume you suspect amyloidosis because of the history of the patient: problem with vertebral column and "purulent" (serous, fibrous, or hemorrhagic) inflammation when patient very young. Now, the ...