biology mcqs
Excretory Products & Their Elimination: MCQs
Test your understanding of excretory products, human excretory system, and kidney function with these multiple-choice questions.
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Showing questions 61 - 80 of 169
61. When the volume of body fluid falls below normal, ADH
When the osmolarity of the blood increases (e.g., due to decreased body fluid volume or dehydration), osmoreceptors in the hypothalamus trigger the release of ADH (Antidiuretic Hormone) from the pituitary gland. ADH then acts on the kidneys to enhance fluid retention. It does this by increasing the permeability of the distal convoluted tubule and collecting tubules/ducts to water, allowing more water to be reabsorbed back into the blood from the filtrate.
62. The reabsorption of water in the kidneys is under the control of a hormone
The reabsorption of water in the distal parts of the kidney tubules, specifically the collecting tubules and collecting ducts, is directly regulated by the hormone Vasopressin or ADH (Antidiuretic Hormone). In the presence of ADH, these tubule walls become permeable to water, allowing its reabsorption and leading to the formation of concentrated urine.
63. The yellow colour of urine is due to
Normal urine is transparent and pale yellow in color. This characteristic color is primarily due to the presence of a pigment called urochrome, which is a breakdown product of hemoglobin.
64. Vitamin excreted by urine in higher vertebrates is
Vitamins are broadly categorized into fat-soluble (A, D, E, K) and water-soluble (B vitamins, C). Fat-soluble vitamins are stored in the body and not readily excreted. Water-soluble vitamins, such as Vitamin C, are not stored in large quantities and any excess intake beyond the body's immediate needs is readily excreted in the urine. *This explanation draws on general biological knowledge as the specific excretion of Vitamin C is not detailed in the provided sources.*
65. Haematuria is the disorder involving
Haematuria is a medical disorder explicitly defined in the sources as the presence of blood in the urine. This indicates an abnormality in the urinary tract or kidneys, as blood cells (like erythrocytes) are normally excluded from the glomerular filtrate.
66. The retroperitoneal kidney is -
The arrangement of the human kidneys is described as Retroperitoneal. This means that the kidneys are fused with the body wall on the dorsal side, and the peritoneal cover (a membrane lining the abdominal cavity) is present only on the ventral side. Therefore, the kidney is uncovered by peritoneum on the dorsal side.
67. Difference between glomerular filtrate and plasma is of -
Glomerular filtrate is formed by the filtration of blood from the glomerulus into Bowman's capsule. This filtrate is chemically similar to blood plasma in terms of small solutes like electrolytes, glucose, amino acids, and urea. However, the key difference is that the filtration barrier in the glomerulus prevents the passage of large molecules and cellular components. Therefore, glomerular filtrate essentially consists of plasma minus large proteins and blood cells.
68. A condition of failure of kidney to form urine is called
Anuria is the medical term for the failure of the kidneys to produce or excrete urine. While not explicitly defined in the disorders list of the provided sources, it contrasts with conditions like polyuria (excessive urine output), haematuria (blood in urine), and glycosuria (glucose in urine). *The term 'Anuria' itself is inferred as a medical term from the context of kidney disorders listed in the source, though its definition is not directly provided.*
69. Diuresis is the condition in which -
The source mentions that 'Diuretic substances like tea, coffee, alcohol etc. increases urine output'. Therefore, diuresis is a condition characterized by an increase in the excretory volume of urine.
70. Presence of RBC in urine is called -
The presence of red blood cells (RBCs) in the urine is medically termed Haematuria. Normally, RBCs are too large to pass through the glomerular filtration barrier, so their presence indicates a problem within the kidney or urinary tract.
71. Ornithine cycle is related to -
The ornithine cycle (also known as the urea cycle) is a metabolic pathway that occurs primarily in the liver. Its main function is to convert highly toxic ammonia (produced from protein metabolism) into less toxic urea, which can then be safely transported in the blood to the kidneys for elimination. Therefore, the ornithine cycle is fundamentally related to excretion of nitrogenous wastes.
72. Volume of urine is regulated by
The volume and concentration of urine are tightly regulated by hormonal control. The key hormones involved are: * ADH (Antidiuretic Hormone): Controls the permeability of the distal convoluted tubule and collecting ducts to water, directly influencing water reabsorption and urine concentration. * Aldosterone: Stimulates the reabsorption of sodium ions (Na+) in the distal convoluted tubule and collecting ducts, and water follows passively. Both hormones work in concert to adjust the final volume and osmolarity of urine based on the body's hydration status.
73. Reabsorption of glucose from glomerular filtrate occurs in
The Proximal Convoluted Tubule (PCT) is the primary and major site of reabsorption in the nephron. It is highly specialized for this function, with its epithelial cells having abundant microvilli (brush border) to increase absorptive area. The source explicitly states that the whole of glucose is reabsorbed in the PCT.
74. Patients of diabeties have glucose in urine because
The presence of glucose in urine, known as glycosuria, is a characteristic of Diabetes mellitus. While the PCT normally reabsorbs all glucose from the glomerular filtrate, in diabetes, blood glucose levels become abnormally high. This means the concentration of glucose in the glomerular filtrate is much higher than its normal amount, exceeding the 'tubular maxima' (the maximum transport capacity) for glucose reabsorption. When the transport proteins in the PCT become saturated, the excess glucose cannot be reabsorbed and is thus excreted in the urine.
75. Pyramids in kidney of man are
The inner renal medulla of the kidney contains conical structures called renal pyramids. The source states that the medulla typically has 8-18 conical renal pyramids. Among the given options, 12 falls within this specified range and is a common number of pyramids found in a human kidney.
76. Na+ and Cl– both are removed by-
Both sodium (Na+) and chloride (Cl–) ions are extensively removed (reabsorbed) from the glomerular filtrate in multiple parts of the nephron: * Proximal Convoluted Tubule (PCT): More than 70% of Na+ and a good quantity of Cl– are reabsorbed here. * Ascending limb of Henle's loop: The thin segment loses NaCl to the interstitial fluid through diffusion, and the thick segment actively transports NaCl out. Therefore, both the Proximal Convoluted Tubule and the Ascending limb of Henle's loop are involved in the reabsorption of Na+ and Cl–.
77. Excretion involves process in which –
Excretion is broadly defined as the process of removal of metabolic wastes from the body. This encompasses the elimination of substances that are no longer useful or are present in excessive, potentially harmful quantities, ensuring the maintenance of internal homeostasis.
78. Which of the following sets of animals produce the same substance as their chief excretory product
Animals are classified as ammonotelic, ureotelic, or uricotelic based on their primary nitrogenous waste product. * Ammonotelic (Ammonia): Aquatic invertebrates (e.g., Amoeba), bony fish, tadpole larva of frog. * Ureotelic (Urea): Cartilaginous fish, amphibians (adult frog), mammals (e.g., camel, antelope, monkey, dog). * Uricotelic (Uric acid): Reptiles (e.g., snake), birds (e.g., pigeon), cockroach (insect). Considering the options: * (1) Camel (urea), housefly (uric acid), snake (uric acid) - Different. * (2) Fish (ammonia), pigeon (uric acid), frog (urea) - Different. * (3) Amoeba (ammonia), ant (uric acid), antelope (urea) - Different. * (4) Frog (adult, urea), monkey (urea), and dog (urea) - All are ureotelic.
79. Column of Bertini is found in –
The renal columns of Bertini are anatomical structures found within the kidney. They are projections of the renal cortex that extend into the renal medulla, situated in the regions between the renal pyramids and calyces.
80. Which feature enables the mammalian kidney to concentrate urine in the medullary region –
The ability of the mammalian kidney to produce concentrated urine is largely attributed to the counter-current mechanism involving the Loop of Henle and vasa recta. This mechanism works to maintain a high osmotic concentration gradient in the interstitial fluid of the renal medulla. This hyperosmolarity, created primarily by the accumulation of NaCl and urea, provides the osmotic pull for water to be reabsorbed from the collecting ducts, thereby concentrating the urine.