Test: Human Excretory System - 2 - NEET MCQ

The Malpighian corpuscle (i.e., glomerulus and Bowman's capsule), PCT (proximal convoluted tubule) and DCT (distal convoluted tubule) of the nephron are situated in the cortical region of the kidney, whereas the loop of Henle dips into the medulla. 
The DCTs of many nephrons open into a straight tube, called as collecting duct, many of which converge and open into the renal pelvis through medullary pyramids in the calyces. Thus, collecting ducts are not found in the cortex of the kidney.
So, the correct answer is option C.

Malpighian corpuscles are a number of small, round, deep-red bodies in the cortex of the kidney, each communicating with a renal tubule. Malpighian corpuscles average about 0.2 mm in diameter. Each capsule is composed of two parts: a central glomerulus and a glomerular capsule or Bowman's capsule. The corpuscles are part of a filtering system through which nonprotein components of blood plasma enter the tubules for urinary excretion

So, the correct answer is 'Cortex'.

Nephrons are the cells of kidney which are composed of a renal corpuscle and a renal tubule.  The renal corpuscle is also known Malpighian body. It consists of cup like double walled structure known as Bowman’s capsule and the bunch of capillaries present in the Bowman’s capsule is known as glomerulus. The blood enters the glomerulus under high pressure from the afferent arteriole and leaves through efferent arteriole.
So, the correct answer is 'Afferent arteriole'.

In the blood supply of the kidney, the vasa recta are a series of straight capillaries in the medulla. They lie parallel to the loop of Henle. These vessels branch off the efferent arterioles of juxta-medullary nephrons (those nephrons closest to the medulla), enter the medulla, and surround the loop of Henle. They participate in a mechanism, called as countercurrent exchange, which is needed for the production of concentrated urine.

The afferent arteriole is of larger diameter than the efferent, due to which blood pressure in the efferent arteriole is higher than the blood pressure in the afferent arteriole. As the blood is forced from a wider vessel to a narrower high resistance is created, producing the back-up of blood in the glomerulus and promoting ultrafiltration.

The afferent vessel and efferent arteriole is arterial in nature. The renal artery enters the kidney and breaks into several arteriole. The arteriole enters the glomerulus as afferent arteriole and supplies oxygenated, urea loaded blood to the glomerulus. The blood is filtered out by ultrafiltration and the deoxygenated blood leaves the glomerulus as efferent arteriole. The efferent arteriole further breaks into capillaries and forms vasa recta which further joins to form the renal vein.

The correct answer is option 'A'.

The Bowman's capsule has an outer parietal layer composed of simple squamous epithelium. The visceral layer, composed of modified simple squamous epithelium.

A loop of Henle is long, a U-shaped portion of the tubule that conducts urine within each nephron of the kidney of reptiles, birds and mammals. The principal function of the loop of Henle appears to be the recovery of water and sodium chloride from the urine. This function allows production of urine that is far more concentrated than blood, limiting the amount of water needed as intake for survival. Many species that live in arid environments such as deserts have highly efficient loops of Henle. So, the loop of Henle is highly developed in animals who lives in the desert than salamanders, freshwater fishes, and lizards.

Therefore, the correct answer is option D.

The release of renin from the juxtaglomerular apparatus (JGA) is triggered by a low glomerular filtration rate (GFR). Renin plays a key role in the renin-angiotensin-aldosterone system, which helps regulate blood pressure and fluid balance in the body.

 The afferent arteriole is a fine branch of the renal artery which has ha wider lumen than the efferent arteriole which carries blood away from the glomerulus. If the afferent arteriole diameter is less than the efferent arteriole, then ultrafiltration is not possible.

Antidiuretic Hormone (ADH), also known as vasopressin, regulates the reabsorption of water in the distal parts of the kidney tubule. It acts on the kidneys to conserve water by reducing the volume of urine expelled from the body.

Blood plasma contains red and white blood cells, blood proteins, glucose, water, nitrogenous wastes, salt. Glomerular filtrate contains glucose, salt, water, nitrogenous wastes. Blood cells and plasma proteins are not filtered through the glomerular capillaries because they are relatively larger in size.

So, the correct answer is 'Proteins'

Through umbilical cord and placenta excretory products of embryo reach mothers blood. Then as usual, mothers blood is filtered in kidneys.

Anuria means non passage of urine, in practice is defined as passage of less than 100 milliliters of urine in a day. Anuria is caused by failure in the function of kidneys. It may also occur because of some severe obstruction like kidney stones or tumours. It may occur with end stage renal disease.

Diuresis is a condition of production of excessive urine. It is a condition when kidney filters more excess of liquids. It is caused due to reduced reabsorption of fluids in the kidney. It can be caused due to excess of blood glucose level during diabetics. The excess glucose can accumulate and block the reabsorption of water. It is also caused during hypercalcaemia where excess of calcium accumulates in the blood. The kidneys may increase urine output in order to balance calcium levels. So, the correct answer is “The excretion of volume of urine increases”.

The glomerular filtrate contains a large amount of water and other dissolved substances such. as urea, uric acid, creatinine, amino acids, glucose; sodium, potassium, vitamins, etc. The blood after filtration flows into efferent renal arterioles.

Animals that excrete excess nitrogen in the form of ammonia are called ammonotelic. Excretion of ammonia occurs in aquatic animals (aquatic invertebrates, fishes, larvae, permanently aquatic amphibia). The route of ammonia diffusion in these animals is through skin, gills or kidneys. In mammals and semi terrestrial adult amphibians, urea is a major nitrogenous excretory product, therefore these animals are called ureotelic.

Hepatic vein is the vein which carries the blood from the liver. 
Hepatic portal vein supplies blood from liver to intestine. 
Dorsal aorta is the renal artery which supplies blood to the kidney. 
The blood in the renal vein will contain less urea than the renal artery, because having passed through the kidney, urea leaves the blood through pressure filtration at the glomerulus with only a small amount being passively reabsorbed at the proximal convoluted tubule.
Thus, the correct answer is option B

The process of excreting ammonia is ammonotelism. Many bony fishes, aquatic amphibians, frog larva i.e., tadpole and aquatic insects are ammonotelic in nature. Ammonia, as it is readily soluble, is generally excreted by diffusion across body surfaces or through gill surfaces (in fish) as ammonium ions. Kidneys do not play any significant role in its removal.

• Assertion (A) is true. The kidneys do have mechanisms to regulate GFR, and the juxtaglomerular apparatus (JGA) plays a crucial role in this regulation.
• Reason (R) is also true. The JGA does release renin when GFR decreases, which leads to increased glomerular blood flow and helps to restore GFR to normal levels.
• The Reason is the correct explanation of the Assertion because it explicitly describes how the JGA functions to regulate GFR in response to its changes. Thus, both the assertion and reason are true, and the reason correctly explains the assertion.