CBSE Questions for Class 11 Medical Biology Excretory Products And Their Elimination Quiz 12 - MCQExams.com

$$\textbf{Correct answer: A}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ In the kidney, the urine is concentrated by actively reabsorbing the water out of the filtrate. 

$$\bullet$$ If there is the removal of excess water which is essential for the body then the reabsorption of water is required.

$$\bullet$$ This is useful to maintain the water balance in the body and to avoid dehydration. 

$$\textbf{Option (B):}$$ 

$$\bullet$$ When the collecting dogs become less permeable to water, the urine produced is not diluted. 

$$\textbf{Option (C):}$$ 

$$\bullet$$ Antidiuretic hormone reduces the urine output as it increases the absorption of water further concentrating the urine. 

$$\bullet$$ This hormone is released from the posterior pituitary gland. It is released to prevent dehydration.

$$\textbf{Option (D):}$$ 

$$\bullet$$ Urine is produced after it completely passes through the distal convoluted tubule. 

$$\bullet$$ At first, due to ultrafiltration the nitrogenous waste along with certain solutes and water enter the Bowman's capsule.

Hence, the correct answer is option (A).

• Blood is filtered at the glomerulus that is a network of fine capillaries present in the Bowman's capsule of a nephron.
  
• The process is known as glomerulus filtration in which fluid, ions, glucose, and nitrogen waste products are removed from the blood.
• The Bowman's capsule collects the filtrate and passes it to the next parts of the nephron, namely the proximal tubule, the loop of Henley and the distal tubule. The filtrate is processed in the tubules finally to form urine.
  

• Acidification of urine is lowering the pH of urine. 
• The concentration of urine takes place in the loop of Henle. 
• Maximum hydrogen secretion takes place in PCT. 
• Potassium, ammonia, hydrogen ions are actively transported into the filtrate in the distal tubule. While $$HCO_3$$$$^-$$ is reabsorbed from the filtrate, which makes the urine concentrated.

Serum does not include formed elements or blood cells and also the clotting factors or proteins as serum is the after clot component of the blood, however, it does contain other albumin and ions. Similarly, glomerular filtate contains ions and  a negligent amount of albumin

So, the correct answer is (B)

Urinary bladder is the organ that stores water. When the sac is empty, it just looks like a pear. It is positioned behind its pubic bone.Urine from the kidneys flows down through ureters and finally reaches the bladder.It gets accumulated in the sac which avoids frequent urination and the volume of water it can bear ranges from 400 to 600 ml.  It leaves the body through urethra.

So, the correct answer is (C)

• The loop of Henle is a U shaped tubule and the vasa recta are tiny capillaries that run parallelly to it.
• Vasa recta is absent or highly reduced in cortical nephrons and well developed in juxtamedullary nephronsl
  

The diameter of afferent arteriole is larger than the efferent arteriole. This increases the volume of blood in glomerulus and increases the filtration rate. This causes the effective filtration pressure which is the total pressure that promotes filtration. 

Solution:

Correct answer is option C.

Explanation for correct option:

• Birds and reptiles are uricotelic (not ureotelic) as they excrete nitrogenous waste uric acid in the form of pellet or paste with a minimum loss of water.
• Uric acid is also less toxic than ammonia or urea. 

• The malpighian body is the filtration unit of the kidney that comprises a cup-shaped structure called the Bowman's capsule and a highly coiled network of capillaries formed by the afferent arteriole called the glomerulus. 
• In PCT, DCT, and collecting duct the concentration of urine takes place. 

• Insufficient filtration will increase the blood urea level because the quantity of urea produced by the liver would not be filtered through the glomerular capsule. 
• As the body is not filtering the blood, there will be an accumulation of fluid in the body.
• Because of less filtration of the blood, the blood volume increases, which leads to an increase in blood pressure.
• Loss of glucose through urine always takes place due to insufficient reabsorption.

• Urine is mainly produced by the kidney. It is a watery solution of waste products, salts, organic compounds, and two important nitrogen compounds: uric acid and urea. The nucleic acids and the proteins constitute the major sources of nitrogen in the body. Uric acid results from nucleic acid decomposition and urea results from amino acid (monomer of proteins) breakdown in the liver. Both of these nitrogenous products can be poisonous to the body and are removed in the form of urine.