Chapter 19: Excretory Products and Their Elimination – Very Short Answer Type Questions
CBSE Class 11 Biology Very Short Answer Questions – Excretory Products and Their Elimination (NCERT)
Course & Examination Details
- Course: CBSE Class 11 Biology
- Prescribed By: Central Board of Secondary Education
- Based On: NCERT
- Unit: Unit V – Human Physiology
- Chapter: Chapter 19 – Excretory Products and Their Elimination
- Question Type: Very Short Answer Questions (VSA)
- Answer Length: 20–30 words
- Exam Utility: CBSE Class 11 Annual Exam, Unit Tests, School Assessments
Section A: Excretory System (Q1–Q20)
Q1. What is excretion?
Answer:
Excretion is the process by which metabolic waste products such as urea, excess salts, and water are removed from the body to maintain internal balance.
Q2. Name the main excretory organ in humans.
Answer:
The kidneys are the main excretory organs in humans, responsible for removing nitrogenous wastes and regulating water and ionic balance.
Q3. Why are humans called ureotelic?
Answer:
Humans are ureotelic because urea is the chief nitrogenous waste excreted in urine.
Q4. Name the components of the human excretory system.
Answer:
The excretory system consists of a pair of kidneys, a pair of ureters, urinary bladder, and urethra.
Q5. Where are kidneys located in the human body?
Answer:
Kidneys are located on either side of the vertebral column in the abdominal cavity, with the right kidney slightly lower than the left.
Q6. What is the function of ureters?
Answer:
Ureters transport urine from the kidneys to the urinary bladder by peristaltic movements.
Q7. Name the outer protective covering of the kidney.
Answer:
The kidney is covered by a tough fibrous capsule that provides protection and maintains its shape.
Q8. What is renal pelvis?
Answer:
Renal pelvis is a funnel-shaped cavity in the kidney that collects urine and leads it into the ureter.
Q9. Define nephron.
Answer:
A nephron is the structural and functional unit of the kidney responsible for urine formation.
Q10. How many nephrons are present in one kidney?
Answer:
Each human kidney contains about one million nephrons.
Q11. Name the two main parts of a nephron.
Answer:
A nephron consists of a renal corpuscle and a renal tubule.
Q12. What forms the renal corpuscle?
Answer:
The renal corpuscle is formed by the glomerulus and Bowman’s capsule.
Q13. What is glomerulus?
Answer:
Glomerulus is a network of capillaries present inside Bowman’s capsule that filters blood plasma.
Q14. Name the first part of the renal tubule.
Answer:
The proximal convoluted tubule is the first part of the renal tubule.
Q15. What is the role of loop of Henle?
Answer:
The loop of Henle helps in concentration of urine by establishing an osmotic gradient in the medulla.
Q16. Name the last part of nephron.
Answer:
The collecting duct is the last part of the nephron that collects urine from several nephrons.
Q17. What are juxtamedullary nephrons?
Answer:
Juxtamedullary nephrons are nephrons with long loops of Henle extending deep into the medulla, important for urine concentration.
Q18. What are cortical nephrons?
Answer:
Cortical nephrons are nephrons located mainly in the cortex with short loops of Henle.
Q19. Name the blood vessel entering the glomerulus.
Answer:
The afferent arteriole carries blood into the glomerulus.
Q20. Name the blood vessel leaving the glomerulus.
Answer:
The efferent arteriole carries blood away from the glomerulus.
Section B: Urine Formation (Q21–Q35)
Q21. Name the three processes of urine formation.
Answer:
Urine formation involves glomerular filtration, selective reabsorption, and tubular secretion.
Q22. Where does glomerular filtration occur?
Answer:
Glomerular filtration occurs in the glomerulus of the nephron.
Q23. What is glomerular filtrate?
Answer:
Glomerular filtrate is the fluid filtered from blood into Bowman’s capsule, similar to plasma but lacking proteins.
Q24. Define glomerular filtration rate (GFR).
Answer:
GFR is the volume of filtrate formed per minute by both kidneys, normally about 125 mL per minute.
Q25. Where does maximum reabsorption occur?
Answer:
Maximum reabsorption of water, glucose, and amino acids occurs in the proximal convoluted tubule.
Q26. What is selective reabsorption?
Answer:
Selective reabsorption is the process by which useful substances are reabsorbed from the filtrate into the blood.
Q27. Name any two substances reabsorbed in PCT.
Answer:
Glucose and amino acids are reabsorbed in the proximal convoluted tubule.
Q28. What is tubular secretion?
Answer:
Tubular secretion is the active transfer of substances like hydrogen and potassium ions from blood into the renal tubule.
Q29. Which part of nephron is mainly involved in secretion?
Answer:
The distal convoluted tubule is mainly involved in tubular secretion.
Q30. What is the role of collecting duct?
Answer:
The collecting duct reabsorbs water under hormonal control and carries urine to the renal pelvis.
Q31. What is counter current mechanism?
Answer:
Counter current mechanism is the process that helps concentrate urine by maintaining an osmotic gradient in the medulla.
Q32. Which structures act as counter current systems?
Answer:
The loop of Henle and vasa recta act as counter current systems.
Q33. Why is descending limb permeable to water?
Answer:
The descending limb allows water reabsorption, increasing osmolarity of filtrate.
Q34. Why is ascending limb impermeable to water?
Answer:
The ascending limb actively transports salts but does not allow water reabsorption.
Q35. What is the normal composition of urine?
Answer:
Urine contains urea, uric acid, creatinine, excess salts, and water.
Section C: Regulation of Kidney Function (Q36–Q50)
Q36. Name the hormone that regulates water reabsorption.
Answer:
Antidiuretic hormone (ADH) regulates water reabsorption in the collecting ducts.
Q37. What is the source of ADH?
Answer:
ADH is secreted by the posterior pituitary gland.
Q38. What is the function of aldosterone?
Answer:
Aldosterone increases sodium reabsorption and potassium excretion in the kidney tubules.
Q39. Which hormone lowers blood pressure by increasing sodium excretion?
Answer:
Atrial natriuretic factor (ANF) lowers blood pressure by promoting sodium excretion.
Q40. What is juxtaglomerular apparatus (JGA)?
Answer:
JGA is a specialized structure near the glomerulus that regulates blood pressure and GFR.
Q41. Which enzyme is released by JGA?
Answer:
Renin is released by the juxtaglomerular apparatus.
Q42. What is micturition?
Answer:
Micturition is the process of expulsion of urine from the urinary bladder.
Q43. Which organ stores urine temporarily?
Answer:
The urinary bladder temporarily stores urine.
Q44. Name one excretory role of lungs.
Answer:
Lungs excrete carbon dioxide and water vapour.
Q45. How does skin act as an excretory organ?
Answer:
Skin excretes sweat containing water, salts, and small amounts of urea.
Q46. Name one disorder caused by kidney failure.
Answer:
Uremia is caused by accumulation of urea in blood due to kidney failure.
Q47. What is dialysis?
Answer:
Dialysis is an artificial process that removes waste products from blood when kidneys fail.
Q48. What is renal calculi?
Answer:
Renal calculi are kidney stones formed by precipitation of salts in the kidney.
Q49. What is glomerulonephritis?
Answer:
Glomerulonephritis is inflammation of the glomeruli affecting filtration.
Q50. Why is kidney transplantation preferred over dialysis?
Answer:
Kidney transplantation restores normal kidney function and provides a long-term solution compared to dialysis.
NCERT & CBSE Compliance Note
✔ Strictly based on NCERT Class 11 Biology
✔ Answer length maintained at 20–30 words
✔ Fully aligned with CBSE board exam pattern
✔ Ideal for quick revision and assessments