Tag: excretion and osmoregulation

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Questions Related to excretion and osmoregulation

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

In the vertebrates, the hormones which control osmoregulation are?

  1. Vasopressin and thyrotropin

  2. Aldosterone and corticotropin

  3. Thyrotropin and corticotropin

  4. Vasopressin and aldosterone
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Kidneys play a very large role in human osmoregulation by regulating the amount of water reabsorbed from glomerular filtrate in kidney tubules, which is controlled by hormones such as antidiuretic hormone(ADH), aldosterone and corticotropin. 

So, the correct answer is 'Aldosterone and corticotropin'

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

A person stranded in the desert faces the risk of severe dehydration. Which of the following will be maximally stimulated to prevent water loss?

  1. Anterior and posterior pituitary

  2. Adrenal cortex and thyroid gland

  3. Hypothalamus and adrenal gland

  4. Adrenal gland and anterior pituitary
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Which one of the following statements is correct with respect to kidney function regulation?

  1. During summer when body loses a lot of water by evaporation,the release of ADH is suppressed

  2. When someone drinks a lot of water, ADH release is suppressed

  3. Exposure to cold temperatures stimulates ADH release

  4. An increase in glomerular blood flow stimulates formation of angiotensin II
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the level of water in blood goes up for example in cold or when we had a lot to drink, the hypothalamus detects the change and sends a message to the pituitary. The release of ADH into the blood is slowed down or even stopped. Without ADH the kidneys will not save as much water and we produce large volumes of dilute urine. The level of water in the blood falls back to the normal level.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

The water is reabsorbed under the influence of ADH. it is

  1. Active reabsorption

  2. Obligatory reabsorption

  3. Facultative

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The reabsorption of water in the earlier parts of the nephron (regardless of a person's state of hydration), independent of ADH is termed as 'obligatory reabsorption of water', whereas the water reabsorption in the distal part of the nephron (in accordance with the body's state of hydration), under the influence of ADH, is termed as 'facultative reabsorption of water'.
In facultative reabsorption, the collecting ducts become more permeable to water due to the effect of ADH, so water is reabsorbed by osmosis. Osmosis is a passive process (the diffusion of water from an area of higher water concentration to an area of lower water concentration), no expenditure of ATP energy is required in it.
Thus water reabsorption under the influence of ADH is facultative and passive reabsorption.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

The major hormones associated with excretion in mammals are

  1. Antidiuretic hormone

  2. Adreno-cortico hormones

  3. Both A and B

  4. Thyroid hormones
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The primary hormone involved in regulating water loss is the antidiuretic hormone (ADH). When the body has excess water, cells in the hypothalamus of the brain respond and send a signal to the pituitary and only a small amount of ADH is released and water is lost. When we are dehydrated these same brain cells cause more ADH to be released and water leaves the collecting duct and is returned to the blood. Thus reducing the volume of urine. Adrenocortico hormones are secreted by adrenal cortex under the influence of adrenocorticotropic hormone. The major adrenal cortex enzymes are mineralocorticoids and glucocorticoids. The mineralocorticoids act on kidney tubules and help in maintaining sodium and potassium balance.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

ADH causes which one of the following?

  1. Increase in reabsorption of water

  2. Decrease in reabsorption of water

  3. Maintenance of equilibrium of Na and Ca ion balance

  4. Maintenance of equilibrium of K ion and carbonate pump
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Vasopressin also known as antidiuretic hormone (ADH), is a neurohypophysial hormone found in most mammals. Its two primary functions are to retain water in the body and to constrict blood vessels. Antidiuretic hormone binds to receptors on cells in the collecting ducts of the kidney and promotes reabsorption of water back into the circulation. In the absence of antidiuretic hormone, the collecting ducts are virtually impermeable to water, and it flows out as urine. 

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Juxta glomerular cells of renal cortex synthesizes an enzyme called

  1. ADH

  2. Oxytocin

  3. Renin

  4. Urochrome
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When renal blood flow is reduced, juxtaglomerular cells in the kidneys convert the prorenin present in the blood into renin and secrete it directly into circulation. Plasma renin then carries out the conversion of angiotensinogen released by the liver to angiotensin I. Angiotensin I is subsequently converted to angiotensin II by the enzyme angiotensin-converting enzyme found in the lungs. Angiotensin II is a potent vasoactive peptide that causes blood vessels to constrict, resulting in increased blood pressure.

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

If there is a deficiency of ADH its effect would be

  1. The volume of urine will increase

  2. The volume of urine will decrease

  3. The pH of urine will change from 4.8 to 8

  4. Secretion of urochrome takes place
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

ADH targets nephrons in kidney to increase water reabsorption and thereby decreasing water content in urine. Inability of neurohypophysial system to produce ADH, causes excess urine production with resultant ion loss from blood. This condition is known as diabetes insipidus (watery urine). 

Since ADH regulates the urine volume, not its pH. Urochrome is the yellow pigment, derived from breakdown of heme, which is deposited in blood and then is excreted by kidney with urine. 

Multiple choice zoology excretion and osmoregulation regulation of urine formation properties of urine and regulation of urine formation coordination in human beings- chemical control

Anti Diuretic Hormone(ADH) acts on the

  1. Collecting tubule of kidney

  2. Loop of Henle

  3. Collecting ducts of testes

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Osmoreceptors in the body are activated by changes in blood volume, body fluid volume and ionic concentration. An excessive loss of fluid from the body can activate these receptors, which stimulate the hypothalamus to release antidiuretic hormone (ADH) or vasopressin from the neurohypophysis. ADH facilitates water reabsorption from latter parts of the tubule (Distal convoluted tubule and Collecting duct), thereby preventing diuresis. An increase in body fluid volume can switch off the osmoreceptors and suppress the ADH release to complete the feedback. ADH mainly acts on collecting ducts of kidney and increase the water reabsorption in this part.