Problem 134 - Objective Biology for NEET

Question

Assertion: Vasopressin is also known as antidiueretic hormone. Reason: Vasopressin stimulates the reabsorption of water and electrolyte by distal tubules and there by reduces diuresis.

Step-by-Step Solution

Answer

Both the assertion and reason are true and the reason accurately explains the assertion.

Step 1: Understanding the Assertion

The assertion 'Vasopressin is also known as antidiuretic hormone' is a statement from biology. This assertion can be validated as true because Vasopressin is indeed another name for the antidiuretic hormone (ADH).

Step 2: Understanding the Reason

The reason 'Vasopressin stimulates the reabsorption of water and electrolyte by distal tubules and thereby reduces diuresis' is a statement explaining how Vasopressin functions. The distal tubules are part of the nephron in the kidneys where the absorption of ions, water, and waste products from the filtered blood takes place. Diuresis is the production of urine. Reabsorption reduces the volume of urine and the loss of electrolytes. Hence, this reason is also true and accurately explains the functioning of Vasopressin.

Step 3: Validation

As both the assertion and the reason are true and the reason accurately explains the assertion, the exercise exercise can be concluded as valid.

Key Concepts

Antidiuretic Hormone

Vasopressin, also called antidiuretic hormone (ADH), plays a crucial role in the body’s ability to maintain water balance. It is produced in the hypothalamus and stored in the pituitary gland. When the body requires more water, ADH is released into the bloodstream.
This hormone helps control the amount of water conserved by the kidneys. Understanding its function is vital as it directly influences our hydration levels and blood pressure.

• Regulates water in the body.
• Influences kidney reabsorption processes.
• Manages blood pressure levels.

The release of ADH is triggered by signals from our body that detect when we are dehydrated or have consumed too much salt. This demonstrates the body’s intrinsic mechanism to maintain homeostasis.

Distal Tubules

Distal tubules are a significant part of the nephron in kidneys, necessary for the reabsorption process. They represent a section where fine adjustments to urine composition occur. When vasopressin is present, these tubules increase their uptake of water and certain ions, concentrating the urine and reducing water loss.
In the absence of adequate function or stimulation, the urine remains dilute. Understanding distal tubules is essential as:

• They balance electrolytes.
• Help in acid-base balance.
• Adjust pH levels of the blood.

Their efficient function is dependent on hormonal signals, including that from ADH. This ensures that the body retains necessary fluids and maintains electrolyte balance.

Diuresis

Diuresis refers to the increased or excessive production of urine. It is a process that can be influenced by various factors such as fluid intake, medications, or hormones like vasopressin.
When you drink a lot of fluid, diuresis ensures that the extra fluid is expelled, while limited fluid intake or the presence of vasopressin decreases diuresis to conserve water.
The rate of diuresis is significant because:

• It helps eliminate excess fluid.
• Affects hydration status.
• Impacts blood pressure regulation.

A balance in diuresis is essential for overall health, and any persistent excessive or decreased urine output should be assessed.

Water Reabsorption

Water reabsorption is a key function of the kidneys in maintaining body water levels. It involves the movement of water from the filtrate in the kidneys back into the bloodstream. This process is heavily influenced by ADH, ensuring that body fluids remain within optimal levels.
Increased water reabsorption leads to concentrated urine, minimizing water loss from the body. This is important because:

• It conserves water.
• Regulates blood volume.
• Supports blood pressure maintenance.

ADH works by increasing the permeability of the kidney tubules, allowing more water to be reabsorbed. This dynamic process ensures that water balance in the body is closely regulated.

Kidney Function

The kidneys are vital organs responsible for filtering blood, removing waste, balancing electrolytes, and controlling blood pressure. Each kidney contains millions of nephrons, which are the functional units responsible for these tasks.
Kidney function goes beyond mere filtration, as it plays a massive role in the endocrine function by releasing hormones and responding to hormones like vasopressin.
Key functions include:

• Waste removal and urine production.
• Regulation of blood pressure and volume.
• Acid-base balance and electrolyte regulation.

The kidneys' ability to respond to hormones like ADH is crucial for maintaining homeostasis, illustrating their essential role in the body.