(a) Mention any two components of blood. (b) Trace the movement of oxygenated blood in the body. (c) Write the function of valves present in between atria and ventricles. (d) Write one structural difference between the composition of artery and veins. OR (a) Define excretion. (b) Name the basic filtration unit present in the kidney. (c) Draw excretory system in human beings and label the following organs of excretory system which perform following functions: (i) form urine. (ii) is a long tube which collects urine from kidney. (iii) store urine until it is passed out.
(a) Mention any two components of blood. (b) Trace the movement of oxygenated blood in the body. (c) Write the function of valves present in between atria and ventricles. (d) Write one structural difference between the composition of artery and veins. OR (a) Define excretion. (b) Name the basic filtration unit present in the kidney. (c) Draw excretory system in human beings and label the following organs of excretory system which perform following functions: (i) form urine. (ii) is a long tube which collects urine from kidney. (iii) store urine until it is passed out.
Option A
(a) Two components of blood:
- Plasma: A fluid matrix in which the cells are suspended. It transports food, carbon dioxide (), and nitrogenous wastes in dissolved form.
- Formed Elements / Blood Cells: This includes Red Blood Cells (RBCs) which transport oxygen, White Blood Cells (WBCs) which fight infections, and Platelets which help in blood clotting.
(b) Movement of oxygenated blood in the body:
- Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left, the left atrium.
- The left atrium relaxes when it is collecting this blood. It then contracts, while the next chamber, the left ventricle, expands, so that the blood is transferred to it.
- When the muscular left ventricle contracts in its turn, the oxygenated blood is pumped out of the heart into the aorta (the main artery), which distributes it to all parts of the body.
(c) Function of valves:
Valves are present between the atria and ventricles to ensure that blood does not flow backwards when the atria or ventricles contract.
(d) Structural difference between arteries and veins:
- Arteries: Have thick, elastic walls because the blood emerges from the heart under high pressure.
- Veins: Have thin walls because the blood is no longer under high pressure, and they possess valves to ensure that the blood flows only in one direction (towards the heart).
Option B (OR)
(a) Excretion:
Excretion is the biological process involved in the removal of harmful, toxic nitrogenous metabolic waste products from the body of an organism.
(b) Basic filtration unit in the kidney:
Nephron (or uriniferous tubule).
(c) Human Excretory System Diagram and Labeling:
- (i) Form urine: Kidneys
- (ii) Long tube which collects urine from kidney: Ureter
- (iii) Store urine until it is passed out: Urinary Bladder
Marking Scheme
- 11 mark
- 21.5 marks
- 31 mark
- 41.5 marks
- 51 mark
- 61 mark
- 73 marks
Hint
Remember that the left side of the human heart handles oxygenated blood, while the right side handles deoxygenated blood. For the excretory system, trace the path of urine from production to elimination.
Quick Oral Answer
The left ventricle has much thicker muscular walls than the left atrium because it has to pump blood to the entire body, which requires overcoming high systemic resistance, whereas the atrium only pumps blood to the adjacent ventricle.
Analysis & Explanation
This question tests the comprehensive understanding of two major life processes: Transportation and Excretion.
- Part (a): Blood consists of a fluid medium called plasma in which cells (RBCs, WBCs, platelets) are suspended.
- Part (b): Oxygenated blood flow is a key part of double circulation. It always enters the left side of the heart from the lungs and is pumped to the systemic circulation via the aorta.
- Part (c): The heart has valves (tricuspid and bicuspid/mitral) to prevent backflow of blood, maintaining a unidirectional flow.
- Part (d): Arteries carry blood away from the heart under high pressure, requiring thick elastic walls. Veins carry blood back to the heart under low pressure, requiring valves to prevent backflow.
- OR Part (a) & (b): Excretion is distinct from defecation (removal of undigested food). The kidney contains millions of filtration units called nephrons.
- OR Part (c): The human excretory system consists of a pair of kidneys, a pair of ureters, a urinary bladder, and a urethra.
Common Mistakes
- 1Confusing the left and right sides of the heart; oxygenated blood is always on the left side.
- 2Confusing excretion with egestion (defecation). Excretion specifically deals with metabolic nitrogenous wastes.
- 3Forgetting to mention that arteries have *elastic* walls, not just thick walls.
Interesting Facts
The total length of all capillaries in a human body is about 100,000 kilometers, which could wrap around the Earth twice!
Your kidneys filter about 180 liters of filtrate daily, but only about 1 to 2 liters are excreted as urine because of massive reabsorption.
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Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2018?
This question carries 5 marks in the CBSE Class 10 Science 2018 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Life Processes" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Transportation and Excretion in Human Beings" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2018 paper?
This is a Long Answer question from Section A in the CBSE Class 10 Science 2018 paper.