All questions of Excretory Products and their Elimination for NEET Exam

The functional structural unit of the kidney is the nephron.

The nephron is the microscopic structural and functional unit of the kidney. It is responsible for the filtration, reabsorption, and secretion of various substances to maintain the body's fluid and electrolyte balance. Each kidney contains millions of nephrons, which work together to perform the vital functions of the kidney.

Components of a nephron:
A nephron consists of several distinct components, each playing a crucial role in the overall function of the kidney. These components include:

1. Renal corpuscle: It is the initial structure of the nephron and is composed of the glomerulus and Bowman's capsule. The glomerulus is a network of tiny blood vessels called capillaries, which function to filter the blood. Bowman's capsule surrounds the glomerulus and collects the filtrate.

2. Proximal convoluted tubule (PCT): After the filtrate is collected in Bowman's capsule, it enters the PCT. This section of the nephron is responsible for reabsorbing most of the filtered water, ions, and nutrients back into the bloodstream.

3. Loop of Henle: The PCT leads into the loop of Henle, which consists of a descending and ascending limb. The loop of Henle plays a crucial role in concentrating the urine by creating a concentration gradient in the surrounding tissue.

4. Distal convoluted tubule (DCT): After passing through the loop of Henle, the filtrate enters the DCT. This section of the nephron is responsible for fine-tuning the reabsorption and secretion of specific ions, such as sodium and potassium.

5. Collecting duct: The DCT leads into the collecting duct, which is responsible for further reabsorption of water and concentration of urine. Multiple nephrons drain into a single collecting duct, which eventually leads to the renal pelvis and out of the kidney.

Functions of the nephron:
The nephron performs several essential functions to maintain homeostasis in the body. These functions include:

1. Filtration: The glomerulus filters the blood, allowing small molecules like water, ions, and waste products to pass through into Bowman's capsule. This process is known as glomerular filtration.

2. Reabsorption: The PCT reabsorbs most of the filtered water, ions, and nutrients back into the bloodstream. This helps maintain the body's fluid balance and prevents excessive loss of valuable substances.

3. Secretion: The DCT is responsible for the secretion of certain substances, such as hydrogen ions and drugs, into the filtrate. This process helps regulate the body's pH and eliminate waste products.

4. Concentration of urine: The loop of Henle and collecting duct play a crucial role in concentrating the urine. By creating a concentration gradient in the surrounding tissue, water can be reabsorbed from the filtrate, resulting in the production of concentrated urine.

In conclusion, the nephron is the functional structural unit of the kidney. It performs the essential functions of filtration, reabsorption, and secretion to maintain the body's fluid and electrolyte balance.

All parts of nephron other than loop of henle lie in the cortex of kidney but the loop of henle lie in medulla of kidney

Bowman's capsule is lined by 'simple squamous epithelium'..option B

Contractile vacuole is responsible to throw excess water that comes from outside to inside the cell. In presence of marine water, due to exosmosis cell start losing water. So, there is a need to preserve water. In that situation, the presence of contractile vacuole will dehydrate the cell. So, contractile vacuole will be disappeared.

Ureter opens into urinary bladder and bladder opens into the urethra.

Visceral peritoneum. a continuation of the parietal peritoneum reflected at various places over the viscera, forming a complete covering for the stomach, spleen, liver, intestines from the distal duodenum to the upper end of the rectum, uterus, and ovaries; it also partially covers some other abdominal organs.

False statement: Renin-Zymogen

Explanation:
• Nephron-Excretion: Nephron is the functional unit of the kidney which removes waste products from the body in the form of urine. Hence, this statement is true.
• Alveoli-Respiration: Alveoli are the tiny air sacs present in the lungs where exchange of gases (oxygen and carbon dioxide) takes place during respiration. Hence, this statement is true.
• Kidney-osmoregulation: The kidneys regulate the water balance in the body by filtering excess water and salts from the blood and excreting them in the form of urine. Hence, this statement is true.
• Renin-Zymogen: Renin is an enzyme secreted by the kidneys that plays a role in regulating blood pressure by converting angiotensinogen (a plasma protein) into angiotensin I. It is not a zymogen (inactive precursor of an enzyme). Hence, this statement is false.

Therefore, the false statement is option D - Renin-Zymogen.

The nephron plus the collecting tubule and collecting duct makes the uriniferous tubule (anatomofunctional unit of the kidney).The uriniferous tubule consists of the nephron and the collecting ducts.The nephron consists of the renal corpuscle(glomerulus and the Bowman’s capsule), proximal convoluted tubules, loop of henle(thick, thin and thick portions) and the distal convoluted tubule.so we can't say nephron is also known as Uriniferous tubules

Answer is option.A

The ans is D).PCT.
Acc. to NCERT nearly all the essential nutrients and 70-80% of the electrolytes and water are reabsorbed by this segment.i.e. PCT

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.

The least toxic form among the excretory products in animals is uric acid.

Explanation:
• Animals excrete waste products that are formed during metabolic processes.
• The excretory products are mainly classified into three types: ammonia, urea, and uric acid.
• Ammonia is highly toxic and water-soluble. It is excreted by aquatic animals, but not by terrestrial animals because of its toxicity.
• Urea is less toxic than ammonia and water-soluble. It is excreted by most terrestrial animals, including humans.
• Uric acid is the least toxic form among the three. It is insoluble in water and is excreted in the form of a paste or a solid.
• Uric acid is the excretory product of birds, reptiles, and insects. It is also excreted by some other animals, such as snails and spiders.
• Uric acid is less toxic than ammonia and urea because it requires less water for its excretion.
• The excretion of uric acid conserves water, which is essential for survival in arid environments.
• In humans, excess uric acid can lead to gout, a painful condition caused by the deposition of uric acid crystals in the joints.

Therefore, uric acid is the least toxic form among the excretory products in animals.

Most kidney stones are calcium stones, usually in the form of calcium oxalate, phosphate, or maleate. Urinary sulfate is a reflection of dietary protein intake, particularly meat, fish, and poultry, which are rich in sulfur-containing amino acids methionine and cysteine. Urinary sulfate can be used to assess dietary protein intake for nutritional purposes. A protein-rich diet has been associated with an increased risk for stone formation. Some patients form stones that are composed of a mixture of magnesium, ammonium, phosphate, and calcium carbonate, which is known as struvite. These stones form as a result of infection with certain types of bacteria that can produce ammonia.CORRECT OPTION IS (D).

Renal corpuscle, also called malpighian body, filtration unit of vertebrate nephrons, functional units of the kidney. It consists of a knot of capillaries (glomerulus) surrounded by a double-walled capsule (Bowman's capsule) that opens into a tubule.

Mammals is ureolatic so urea is produced.

The renal vein takes blood away from the kidney. The process starts with renal artery which enters the kidney as afferent arteriole. It carries the urea loaded blood into the glomerulus of the kidney. The blood is filtered by the glomerulus into the Bowman's capsule and runs parallel to the loop of Henle. The urea is absorbed into the nephric filtrate by the process of tubular secretion in the loop of Henle, distal convulated tubule and collecting duct. The process of tubular secretion helps to secrete the urea from the blood to the collecting duct which is finally excreted in form of urine. The purified blood comes from the kidney through the renal vein and drained into vena cava outside kidney.
So, the correct answer is 'Renal vein'.

Kidney, with renal papilla labeled at upper right. The renal papilla is the location where the renal pyramids in the medulla empty urine into the minor calyx in the kidney. Histologically it is marked by medullary collecting ducts converging to form a papillary duct to channel the fluid.

Renal cortex, renal medulla and pelvis all are the parts of kideny. so ans. is all of the above.

Based on toxicity-ammonia>urea>uric acid.
Uric acid is least toxic and least soluble in water... And it requires less water for excretion.

In the kidneys the receptors for ADH are found on the nephrons; the microscopic functional units of the kidneys. The parts of the nephron where the receptors are specifically located are on the distal convoluted tubule and collecting duct .

When we do any hard physical activity then body losses more salts in the form of sweat and for that excretion of salts water is required. so workers loss more than normal quantity of water therefore they suffer from dehydration...

Loop of Henle. The Loop of Henle (LoH) is a long, straight, tubular segment connecting the proximal tubule to the distal convoluted tubule and lies parallel to the collecting ducts. The LoH descends from the cortex or medulla (depending on the size/length of the nephron) into the papilla of the kidney.

This fissure is a hilum that transmits the vessels, nerves, and ureter. From anterior to posterior, the renal vein exits, the renal artery enters, and the renal pelvis exits the kidney.

Renin also known as an angiotensinogenase is an aspartic protease protein and enzyme secreted by the kidneys in to the circulation in the response to the renal hypotension and hypernatremia sympathetic nerve activation

Nephron functional unit of kidney the structure that actually produces urin in the process of removing waste and excess substance from the blood.there are about 1000,000 nephron in each human kidney. nephron is the minet or microscope the renal cropuscle consists of a tuft of capillaries called a glomerulus and a cup- shaped structure called bowmens there types of nephron can be distinguished superficial ,midcortical and juxtamedullary nephron. A healthy adults has 1 to 1.5 million nephron per kidney. sir William bowmen first baronet discovered nephron .

Connecting tubules/duct is not considered a part of uriniferous tubule (as it is common to many nephrons)

Afferent arterioles has more diameter than efferent. and that's why there is generation of filtration pressure.

The function of heart is different from the rest options in a way that heart is an organ that pumps blood throughout the body tissues and removing carbon dioxide and other wastes. And hence does not helps in excretion.