which of the following statements about aldosterone is not correct

Question 1

Which of the following statements about aldosterone is NOT correct?

Aldosterone is stimulated by decreased plasma sodium levels and increased plasma potassium levels. Aldosterone increases the number of passive sodium channels in the luminal membrane of the distal tubule and collecting duct, thus aiding sodium reabsorption. Aldosterone increases sodium reabsorption by increasing the number of Na+-K+ ATPase pumps in the luminal membrane of the proximal tubule. Aldosterone is produced in the adrenal cortex.

2. Which of the following statements about ADH (antidiuretic hormone) is correct? ADH is released by the posterior pituitary gland. ADH inserts water channels into the luminal membrane of the proximal tubules. ADH is synthesized by the adrenal gland and works in the kidney. ADH would increase urine volume.

3. In severe dehydration or blood loss, what would be the levels of ADH and what would be the urine flow rate? ADH – high; high urine flow rate (16 ml/min) ADH – low; low urine flow rate (0.25 ml/min) ADH – high; low urine flow rate (0.25 ml/min) ADH – low; high urine flow rate (16 ml/min)
Question 2

Which of the following statements about aldosterone is not correct?

A) Aldosterone increases sodium reabsorption by increasing the number of Na+-K+ ATPase pumps in the luminal membrane of the proximal tubule

B) Aldosterone is stimulated by decreased plasma sodium levels and increased plasma potassium levels.

C) Aldosterone is produced in the adrenal cortex.

D) Aldosterone increases the number of passive sodium channels in the luminal membrane of the distal tubule and collecting duct, thus aiding sodium reabsorption.


Question 3

What does ADH determine in regards to the filtrate osmolarity? ADH ADH, or anti diuretic hormone, is a hormone released by the hypothalamus in response to dehydration. ADH acts to increase the amount of water reabsorbed by activating aquaporins, or water channels, in the tubules of the kidneys.
Question 4

Briefly explain how SIADH (Syndrome of Inappropriate ADH secretion) can result in hyponatremia? Can ADH secretion affect oxytocin secretion? Antidiuretic Hormone: Antidiuretic hormone (ADH) is a neurotransmitter that is responsible for regulating the water and nutrients in the body. It is produced by the hypothalamus and is stored in the lobe of the pituitary gland until it is required.
Answer to question 1

1.option C is wrong.

b. Right because it acts on DCT and CT on luminal side and enhance sodium reabsorbption.

c. wrong because aldosterone acts on collecting tubule not proximal tubule.

d. right: because aldosterone is secreted by adrenal cortex(zona glomerulosa)

2. correct statements is option a.

a. right: ADH is released by posterior pituitary

There are only two hormones which are released from posterior pituitary (but formed in hypothalamus) that are oxytocin and vasopressin(ADH).

b. wrong : since ADH inserts water channels in luminal membrane of collecting tubule and not proximal tubule.

c.wrong: Adh is synthesised in hypothalamus not adrenals.

D. wrong : ADH itslf tells it is a hormone that prevent diuresis . therfore it decreases urine output.

3.In severe dehydration and blood loss there is beed to conserve water therefore the hormone that conserves wateri.e. ADH will increase and urine flow rate will be low to conserve water .

Hence the correct answer is option c. ADH high and urine flow rate low.

rest other options are ruled out.


Answer to question 2

The correct answer is; D) Aldosterone increases the number of passive sodium channels in the luminal membrane of the distal tubule and collecting duct, thus aiding sodium reabsorption.

Aldosterone causes the transcription of the gene encoding the sodium-potassium ATPase, which causes an increase in the number of sodium pumps in the tubule membranes.


Answer to question 3

Answer and Explanation: ADH causes a retention of water, and therefore dilutes the concentration of solutes, or reduces the osmolarity. ADH is activated by sensors that detect a change in the body’s osmolarity.
Answer to question 4

Answer and Explanation: The syndrome of inappropriate ADH secretion (SIADH) is a disease that occurs when the body is unable to excrete water due to suppression of antidiuretic hormone. When this hormone is imbalanced the urine output decreases leading to a disease called hyponatremia. Antidiuretic hormone and oxytocin are neuropeptide hormones that are produced by the hypothalamus. These hormones regulate the water balance in the body. Since the antidiuretic hormone is secreted during stressful situations, the oxytocin secretion decreases during this period because oxytocin is a hormone that triggers a sense of love and happiness.

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