Excretory Products And Their Elimination Module

Q1. Nitrogenous waste is excreted in the form of pellets or paste by

1. Pavo
2. Ornithorhynchus
3. Salamandra
4. Hippocampus

Answer – 1, Pavo
Explanation: Nitrogenous waste is excreted as pellets or paste by these animals. This excretion process, known as “uricotelism”, allows the organism to conserve water and eliminate nitrogenous waste products as a paste or a dry powder.

Q2. Which one of the following hormones reduces blood pressure?

1. Antidiuretic hormone
2. Atrial Natriuretic factor
3. Aldosterone
4. Angiotensin-ll

Answer – 2, Atrial Natriuretic factor
Explanation: The hormone responsible for reducing blood pressure is the Atrial Natriuretic Factor (ANF), released from the walls of the atria in response to increased blood pressure. ANF acts to reduce sodium and water retention, as well as stimulate vasodilation, resulting in decreased blood pressure. Ultimately this helps maintain homeostasis of the body’s internal environment.

Q3. The normal value of GFR is approximate:

1. 650 ml/min
2. 180 ml/min
3. 180 ml/day
4. 125 ml/min

Answer – 4, 125 ml/min
Explanation: The normal value of GFR is approximately 125 ml/min. Understanding how to interpret the results of measuring GFR levels is crucial, as it can indicate various diseases such as kidney malfunction or renal failure.

Q4. What is used as an osmolyte in human beings to increase medullary interstitial osmolality during urine concentration?

1. TMAO
2. Urea
3. Both a and b
4. Uric acid

Answer – 2, Urea
Explanation: Urea is the main osmolyte used in humans to increase medullary interstitial osmolality during urine concentration. Urea is synthesized in the liver and then released into the blood, which can be taken up by the kidneys and reabsorbed back into the body. Uric acid and TMAO are also present in urine but are not typically used as osmolytes for this purpose.

Q5. The proximal convoluted tubule is lined by the following:

1. Simple cuboidal epithelium
2. Simple columnar epithelium
3. Simple cuboidal brush-bordered epithelium
4. Simple columnar brush-bordered epithelium

Answer – 3, Simple cuboidal brush-bordered epithelium
Explanation: The Simple cuboidal brush-bordered epithelium lines the proximal convoluted tubule. It has brush border microvilli that help absorb electrolytes and other substances. It also has different transporters that add to its function as an absorbent structure.

Q6. Which of the following factors contributes to the formation of concentrated urine?

1. Hydrostatic pressure during glomerular filtration.
2. Low levels of antidiuretic hormone.
3. Maintain hyperosmolarity to the inner pontomedullary stroma.
4. Secretion of erythropoietin by the juxtaglomerular complex.

Answer – 2, Low levels of antidiuretic hormone
Explanation: Low levels of antidiuretic hormone (ADH) contribute to the formation of concentrated urine.

Vasopressin is a hormone produced by the hypothalamus and released by the posterior pituitary gland. It regulates the body’s water balance by controlling kidney reabsorption.

Low ADH levels result in reduced water reabsorption by the kidneys, resulting in dilute urine due to a larger volume of water in the urine.

Conversely, when ADH levels are high, the kidneys become more permeable to water, allowing for increased water reabsorption and more concentrated urine.

Q7. Which of the following statements is incorrect?

1. ADH prevents the conversion of angiotensinogen in blood to angiotensin
2. Aldosterone promotes water reabsorption
3. ANF promotes sodium reabsorption
4. Renin causes vasodilation

Answer – 3, ANF promotes sodium reabsorption
Explanation: Atrial natriuretic peptide (ANF) is a hormone produced by the heart’s atria in response to increased blood volume and pressure. Its primary function is to promote natriuresis, which is the excretion of sodium (Na+) in the urine. ANF acts on the kidneys to inhibit sodium reabsorption, increasing sodium excretion and water loss. It helps reduce blood volume and blood pressure.

Q8. A fall in glomerular filtration rate (GFR) activates

1. posterior pituitary to release vasopressin
2. adrenal medulla to release adrenaline
3. juxtaglomerular cells to release renin
4. adrenal cortex to release aldosterone

Answer – 3, juxtaglomerular cells to release renin
Explanation: In response to specific signals, including a decrease in glomerular filtration rate, juxtaglomerular cells produce and release the enzyme renin.

In response to decreased GFR, juxtaglomerular cells release renin into the bloodstream, reducing blood flow to the glomerulus.

In the renin-angiotensin-aldosterone system (RAAS), a hormonal cascade that controls blood pressure and fluid balance, renin plays a crucial role. It converts inactive plasma proteins, angiotensinogen, into angiotensin I when released. Ultimately, angiotensin II, a potent vasoconstrictor, is produced due to these enzymatic reactions.

It then stimulates the release of aldosterone from the adrenal cortex, promoting sodium and water reabsorption in the kidneys, which increases blood pressure and blood volume.

Q9. The cone-shaped kidney tissue is called ____.

1. Renal Pelvis
2. Renal Calculi
3. Renal Pyramids
4. Renal Vasculitis

Answer – 3, Renal Pyramids
Explanation: The cone-shaped kidney tissue is called the renal pyramid. It is responsible for filtering waste products from the blood and producing urine stored in the renal pelvis before being eliminated. Kidney stones are small, hard masses of mineral crystals that can form in different urinary system parts. Renal vasculitis refers to inflammation of the blood vessels that supply the kidneys with oxygen-rich blood.

Q10. Vasa recta in cortical nephrons:

1. Arises from afferent arteriole rather than efferent arteriole
2. Does not get involved in the counter-current exchange with the loop of Henle
3. Carries deoxygenated blood rich in urea
4. Is absent or highly reduced

Answer – 4, Is absent or highly reduced
Explanation: Vasa recta is a network of blood vessels associated with the juxtamedullary nephrons in the kidney. There are two types of nephrons: cortical and juxtamedullary.

As a result, cortical nephrons, which comprise most kidney nephrons, have a shorter Henle loop that does not extend deeply into the medulla. As a result, the vasa recta associated with cortical nephrons is either absent or highly reduced compared to the vasa recta associated with juxtamedullary nephrons.

The vasa recta associated with juxtamedullary nephrons plays a crucial role in the counter-current exchange mechanism, establishing and maintaining the medulla’s concentration gradient. As a result, water and solutes from the filtrate can be reabsorbed.

The vasa recta associated with cortical nephrons, on the other hand, serves a different purpose. It mainly supplies oxygen and nutrients to cortical tissues and is not extensively involved in the countercurrent exchange with the loop of Henle. The blood carried by cortical nephrons is oxygenated and not particularly rich in urea.

Q11. What is the condition of urea accumulation in the blood?

1. renal calculi
2. Glomerulonephritis
3. uremia
4. Ketonuria

Answer – 3, Uremia
Explanation: The condition of accumulation of urea in the blood is termed Uremia. Urine typically contains urea, but if there is an excessive buildup of this substance, it can lead to serious health problems. Uremia is characterized by frequent urination, swelling, and fatigue. It can also cause kidney failure or damage if left untreated.

Q12. Which one of the following is also known as an antidiuretic hormone?

1. Oxytocin
2. Vasopressin
3. Adrenaline
4. Calcitonin

Answer – 2, Vasopressin
Explanation: Vasopressin, also known as antidiuretic hormone (ADH), is produced in the pituitary gland. It helps to regulate the body’s water levels by controlling how much urine is released from the kidneys. It also helps to constrict blood vessels and increase heart rate and blood pressure.

Q13. What is most likely the cause of albumin appearing in urine?

1. Increase in blood pressure.
2. Decrease in the blood osmotic corpuscles
3. Damage to the Malpighian corpuscles
4. Damage to the proximal convoluted tubules

Answer – 3, Damage to the Malpighian corpuscles
Explanation: The most likely cause of albumin appearing in urine is “damage to the Malpighian corpuscles” (also known as the renal corpuscles), which includes damage to the filtration barrier in the glomerulus. The other options listed (increased blood pressure, decreased blood osmotic pressure, and damage to the proximal convoluted tubules) may contribute to kidney disease. Still, they are not directly responsible for the appearance of albumin in the urine.

Q14. What is the content of glomerular filtrate?

1. Urea, sodium chloride, fibrinogen, and water
2. Glucose, amino acids, urea, oxytocin, and calcitonin
3. Both (a) and (b)
4. Urea, glucose, salts, and water

Answer – 4, Urea, glucose, salts and water
Explanation: The content of glomerular filtrate includes urea, glucose, salts, and water. This filtrate is formed in the kidneys and contains small molecules such as glucose and amino acids customarily filtered from the bloodstream. It also contains electrolytes such as sodium chloride, which help to maintain the concentration of ions in the body.

Q15. “Columns of Bertini” are formed in the kidneys of mammals by extending?

1. Medulla into the cortex
2. Cortex into the medulla
3. Medulla into the pelvis
4. Pelvis into the ureter

Answer – 2, Cortex into the medulla
Explanation: Bertini’s columns are formed in mammals’ kidneys by extending the medulla into the cortex. These columns enable the kidney to filter out waste from the blood and excrete it through the ureter.