Excretory System MCQ Quiz in मल्याळम - Objective Question with Answer for Excretory System - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is Descending limb: permeable to water, concentrates filtrate; Ascending limb: impermeable to water, dilutes filtrate

Explanation:

• Reabsorption is minimum in its ascending limb. However, this region plays a significant role in the maintenance of high osmolarity of medullary interstitial fluid.
• The descending limb of the loop of Henle is permeable to water but almost impermeable to electrolytes. This concentrates the filtrate as it moves down.
• The ascending limb is impermeable to water but allows the transport of electrolytes actively or passively. Therefore, as the concentrated filtrate passes upward, it gets diluted due to the passage of electrolytes to the medullary fluid.

The correct answer is Option 2 i.e. Urethra.

Explanation-

The urethra is not a structure of the kidney.

The urethra is a tubular structure that is part of the urinary system. Its main function is to transport urine from the bladder, where it is stored before micturition, to the outside of the body.

Anatomy:

The structure of the urethra varies between males and females, primarily due to its role in the male reproductive system.

• In males, the urethra is approximately 20 centimeters long and travels through the prostate gland and penis. 
• In females, the urethra is significantly shorter, averaging about 4 centimeters in length. It extends from the bladder neck to the external urethral orifice located above the vaginal opening and does not have distinct sections like the male urethra.

Function:

• The primary function of the urethra is to convey urine from the bladder to the outside of the body during the act of micturition (urination).
• In males, it also serves a reproductive function by enabling the passage of semen during ejaculation.

The other structures listed - cortex, medulla, and pelvis - are all parts of the kidney. 

• Cortex: This is the outer layer of the kidney, which contains many blood vessels and where the initial stages of urine filtration occur.
• Medulla: Located beneath the cortex, the medulla contains the renal pyramids and is where the majority of urine concentration takes place.
• Pelvis: The renal pelvis is a funnel-shaped space in the innermost part of the kidney. It collects urine output from the collecting ducts and funnels it into the ureters.

So, the urethra is the structure that does not belong to the kidney.

Important Points

• Nephron is the functional unit of kidney and it has two parts.
  • The glomerulus
  • The renal tubule
• Glomerulus is a tuft of capillaries formed by the Afferent and Efferent arteriole.
• Glomerulus is enclosed by a cup like structure called Bowman's capsule.
• Glomerulus and Bowman's capsule together form the malpighian body or renal corpuscle.
• This tubule continues to form the Proximal Convoluted tubule (PCT), then continues to the Henle's loop and lastly the Distal Convoluted Tubule (DCT).
• DCT further end up in the collecting ducts.
• Urine formation process takes place in three steps, that takes place in different parts of a nephron.
  • Glomerular filtration
  • Tubular reabsorption
  • Tubular secretion.

Key PointsGlomerulus - 

• The filtration of the blood in the glomerulus occurs due to the the glomerular capillary blood pressure through 3 layers.
  • endothelium of glomerular blood vessels.
  • epithelium of Bowman's capsule
  • the basement membrane between two layers
• As a result the blood is filtered very finely through these membranes.
• Therefore fine filtration process of blood in Bowman's capsule is called Ultrafiltration of blood.

Proximal Convoluted tubule - 

• PCT is lined by brush bordered simple cuboidal epithelial cells.
• This helps in increasing the area of reabsorption.
• Around 70-80 % of the electrolytes and the essential nutrients are reabsorbed into the PCT.

Henle's Loop - 

• This the part which plays a major role in Maintenance of high osmolarity.
• The decending limb of henle's loop is impermeable to the electrolytes but is permeable to water and this concentrates the filtrate.
• The ascending limb is impermeable to water but is permeable to the electrolytes.
• Therefore concentrated filtrate gets diluted as it ascends through the loop due to the passage of the electrolytes.

Distal Convoluted tubule - 

• It plays the role in conditional reabsorption of water and Na²⁺.
• It is responsible for the reabsorption of HCO₃ ions and selective secretion of Hydrogen and potassium ions and ammonia to maintain the pH.
• It also helps in maintaining the sodium- potassium balance in the body.

From the above explanation we can understand that the correct answer is Option 4.

Concept:

• Metabolic activities result in the accumulation of nitrogenous wastes in the body. These wastes need to be eliminated from the body.
• The process by which nitrogenous wastes are removed from the body is called excretion.
• The organs that help in the filtration of blood and the separation of nitrogenous waste from it are called excretory organs.
• In vertebrates, kidneys are the main excretory organs.
• Kidneys are flattened bean-shaped structures that are found in a pair in the abdominal cavity.
• The structural and functional unit of the kidney is called nephrons.
• It carries out the filtration of blood and helps in the elimination of nitrogenous waste from the body.
• Any malfunctioning in the kidney can lead to serious ailments which in some cases can even prove to be fatal.
• Some of the common kidney disorders seen in humans are kidney stones, kidney infections, acute kidney injury, proteinuria, etc.

Explanation:

Option 1: Renal calculi - INCORRECT

• Renal calculi refer to stones formed in the kidney.
• These stones are crystallized salts that get deposited anywhere from the kidney tubules to the external opening. Thus hampering the functioning of the urinary system.
• The stones so formed vary in their composition and can be of many types.
• Calcium stones, struvite stones, uric acid stones, and cystine stones are some types of renal calculi.

Option 2: Glomerulonephritis - INCORRECT​

• Glomerulonephritis refers to inflammation of the glomeruli of the kidneys.
• In many cases, it is a result of one's immune system attacking healthy body tissue.

Option 3: Uremia - CORRECT

• Accumulation of urea in the blood is called uremia.
• The normal range of urea in the blood is 0.01% - 0.03%.
• However, if the urea in the blood rises above 0.05% the condition is categorized as uremia.
• Uremia can lead to kidney failure.

Option 4: Ketonuria - INCORRECT

• Ketonuria refers to the condition of an abnormally high amount of ketone and ketone bodies in the urine.
• It is seen in patients with diabetes mellitus that have very high blood sugar levels.​

The correct answer is Tadpole of frog

Explanation:

Different organisms have evolved different methods of excretion based on their habitat and physiology. The primary forms of nitrogenous waste excreted by living organisms are ammonia, urea, and uric acid.

• Ammonotelic: Organisms that excrete nitrogenous waste as ammonia are called ammonotelic. Many bony fishes, aquatic amphibians, and aquatic insects are ammonotelic in nature.
• Ureotelic: Organisms that excrete nitrogenous waste primarily as urea are called ureotelic. Urea is less toxic than ammonia and requires less water for its excretion. Mammals, many terrestrial amphibians and marine fishes mainly excrete urea and are called ureotelic animals.
• Uricotelic: Organisms that excrete nitrogenous waste as uric acid are called uricotelic. This method is seen in birds, reptiles, and some terrestrial arthropods. Uric acid is less toxic and requires less water to be excreted, which is advantageous for animals in arid environments

The correct answer is (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)

Explanation:

• Inside the kidney, there are two zones, an outer cortex and an inner medulla.
• The medulla is divided into a few conical masses (medullary pyramids) projecting into the calyces (sing.: calyx).
• The cortex extends in between the medullary pyramids as renal columns called Columns of Bertini
• Each kidney has nearly one million complex tubular structures called nephrons
• Each nephron has two parts – the glomerulus and the renal tubule.
• Glomerulus is a tuft of capillaries formed by the afferent arteriole – a fine branch of renal artery. Blood from the glomerulus is carried away by an efferent arteriole.

Therefore, the correct match is

• (a) Medullary Pyramids - (ii) Conical masses in the medulla
• (b) Cortex - (iv) Outer layer between pyramids
• (c) Columns of Bertini - (i) Renal columns
• (d) Nephrons - (iii) Glomerulus and renal tubule

The correct answer is Ascending limb of Henle’s loop, dilutes the filtrate

Explanation:

• Reabsorption is minimum in its ascending limb. However, this region plays a significant role in the maintenance of high osmolarity of medullary interstitial fluid.
• The descending limb of the loop of Henle is permeable to water but almost impermeable to electrolytes. This concentrates the filtrate as it moves down.
• The ascending limb is impermeable to water but allows the transport of electrolytes actively or passively.
• Therefore, as the concentrated filtrate passes upward, it gets diluted due to the passage of electrolytes to the medullary fluid.

The correct answer is: Produces more dilute urine when the collection ducts become less permeable to water.

Explanation:

The human kidney plays a critical role in maintaining fluid and electrolyte balance, as well as excreting waste products. Among its various functions, it does not store glycogen, nor does it actively transport water out of the filtrate to concentrate urine. Instead, the kidney employs osmosis to reabsorb water based on hormonal signals. Specifically, the production of more dilute urine occurs when the collecting ducts of the nephron become less permeable to water. This typically happens when antidiuretic hormone (ADH) levels are low, resulting in less water being reabsorbed and more water remaining in the filtrate, thus leading to the production of dilute urine.

1. Is responsible for the storage of nutrients such as glycogen: This statement is incorrect. The storage of glycogen primarily occurs in the liver and muscles. The kidneys do not store glycogen or other nutrients in significant amounts.
2. Concentrates the urine by actively transporting water out of the filtrate: This statement is incorrect. The kidneys concentrate urine by reabsorbing water from the filtrate in the nephrons, primarily in the collecting ducts, driven by osmotic gradients in the renal medulla. However, water reabsorption is a passive process due to osmotic gradients, not an active transport mechanism.
3. Produces more dilute urine when the collection ducts become less permeable to water: This statement is correct. When the collecting ducts become less permeable to water, less water is reabsorbed from the filtrate back into the bloodstream. This primarily occurs when antidiuretic hormone (ADH) levels are low. As a result, more water remains in the filtrate, leading to the production of more dilute urine.
4. Responds to antidiuretic hormone by increasing urine output: This statement is incorrect. ADH (also known as vasopressin) actually decreases urine output. It makes the collecting ducts more permeable to water, leading to more water being reabsorbed back into the bloodstream, thus concentrating the urine and reducing its volume.

Therefore, the correct answer is: Produces more dilute urine when the collection ducts become less permeable to water.

Concept: 

• Hormones are the organic substances secreted by the endocrine glands that have a definite physiological effect on their target site.
• The hormones are released directly into the bloodstream from where it is carried to the target organ.
• The effects of hormones can be either excitatory or inhibitory.
• Aldosterone, testosterone, prolactin, glycogen, etc. are some examples of hormones that are produced in the human body.
• Hormones such as vasopressin, renin, aldosterone, etc. play an important role in the formation of urine in the uriniferous tubules of the kidneys.

Explanation:

• Option 1: ADH – Prevents the conversion of angiotensinogen in blood to angiotensin - INCORRECT​
  • ADH is secreted in response to an increase in osmotic pressure of the blood which is due to the loss of water from the body.
  • ADH stimulates the DCT of nephrons to reabsorb more water thus making the urine concentrated.
  • It is also a vasoconstrictor and is released in response to low blood pressure.
  • Angiotensin like ADH is a vasoconstrictor and it increases blood pressure.
  • It enhances the reabsorption of Na⁺, Cl^-, and water.
  • Thus ADH does not prevent the conversion of angiotensinogen in blood to angiotensin since angiotensin too is a vasoconstrictor like ADH.
• Option 2: Aldosterone – Facilitates water reabsorption - CORRECT​
  • Aldosterone is a hormone secreted by the adrenal cortex in response to the renin-angiotensin II- aldosterone system.
  • It stimulates DCT and collecting ducts to reabsorb more Na⁺, and water and thus increases the blood pressure and volume.
  • Thus aldosterone facilitates water reabsorption.
• Option 3: ANF – Enhances sodium reabsorption - INCORRECT​
  • Atrial Natriuretic Factor (ANF) is released by the atrial walls of the heart in response to increased blood volume and increased blood pressure.
  • ANF acts on kidneys by inhibiting the reabsorption of Na⁺ and Cl^- ions from the collecting duct.
  • It also inhibits the release of renin, ADH, and aldosterone.
  • Thus ANF inhibits sodium reabsorption and does not enhance it.
• Option 4: Renin – Causes vasodilation - INCORRECT​
  • Renin is a hormone released by the cells of the Juxtaglomerular apparatus (JGA) of the kidney.
  • It is released in response to low blood pressure.
  • Renin acts on Angiotensinogen and converts it into Angiotensin I.
  • Angiotensin I is then converted to Angiotensin II by the Angiotensin-converting enzyme (ACE).
  • Angiotensin II in turn acts as a vasoconstrictor and increases blood pressure.
  • It enhances the reabsorption of Na⁺, Cl^-, and water.
  • It also stimulates the release of aldosterone from the adrenal cortex.
  • Thus renin causes vasoconstriction and not vasodilation.

So the correct answer is option 2.

The correct answer is Hemodialysis 

Explanation:-

Excretion: Excretion is the process by which waste products, such as urea, are removed from the body.

• Urea, a nitrogenous waste generated from the breakdown of proteins, is primarily excreted by the kidneys.
• It is filtered from the blood by the kidneys and then eliminated from the body through urine.
• Therefore, while excretion is involved in removing urea from the blood, it is not a specific process used solely to remove urea from the blood but rather a general term for the removal of waste products from the body.

Digestion: Digestion is the process by which food is broken down into smaller molecules that can be absorbed and utilized by the body.

• It primarily occurs in the digestive system, starting from the mouth, through the stomach and intestines, where enzymes break down food into nutrients.
• Urea, however, is not formed as a result of digestion but rather as a waste product of protein metabolism in the liver.
• Therefore, digestion is not directly involved in removing urea from the blood.

Hemodialysis: Hemodialysis is a medical procedure used to remove waste products and excess fluids from the blood when the kidneys are unable to perform this function adequately.

• During hemodialysis, blood is circulated through a dialysis machine that contains a semipermeable membrane.
• This membrane allows waste products like urea, along with excess fluids, to diffuse out of the blood and into a dialysate solution. The cleansed blood is then returned to the body.
• Hemodialysis is particularly effective in removing urea from the blood in individuals with kidney failure or impaired kidney function.

Sweating: Sweating is the process by which the body releases heat and regulates its temperature through the evaporation of sweat from the skin's surface.

• Sweat primarily consists of water and electrolytes, such as sodium and chloride, and is not a significant route for urea excretion. While small amounts of urea may be excreted through sweat, the main excretory route for urea is through the kidneys in urine, rather than through sweat glands.

In summary, while excretion is involved in removing urea from the blood, hemodialysis is the specific medical procedure used for this purpose in cases of kidney dysfunction or failure. Digestion is not directly related to urea removal, and sweating plays a minor role in urea excretion compared to the kidneys.

Conclusion:-Hemodialysis is used to remove urea from the blood