Topics:
Animal Physiology, Animal Refresher
True Statements About RBC
Which of the following is true about RBC-
- Largest size of RBC is found in dog while smallest is in goat
- Maximum numbers of RBC per μl of blood are found in goat
- Dog's RBC are typically biconcave
- All the above — Correct Answer
Explanation:
Correct Answer: All the above
All three statements about RBC are correct and important for competitive exams.
Statement-wise Explanation
- a) Largest RBC diameter: Dog (7 μm); Smallest: Goat (4 μm). Among domestic animals, dog has the largest individual RBC and goat has the smallest.
- b) Maximum RBC count per μl: Goat. Goat has the highest RBC count (~10–18 million/μl). Smaller RBC size is compensated by higher numbers to maintain O₂-carrying capacity. Cattle: ~7 million RBC/μl as comparison.
- c) Dog RBC are biconcave disc-shaped — like all mammalian RBCs, the biconcave shape maximizes surface area-to-volume ratio for efficient gas exchange and gives flexibility to pass through capillaries.
RBC Size, Number & Lifespan Summary
- Largest RBC: Dog (7 μm) | Smallest RBC: Goat (4 μm)
- Highest RBC count/μl: Goat
- Lifespan: Chicken (20–30 days) → Cat (70 days) → Lamb/Calf (50–100 days) → Dog/Human (120 days) → Ruminants (125–150 days) → Horse (140–150 days)
- Birds have nucleated RBC and nucleated thrombocytes (unlike mammals)
Cell Size Order
WBC > RBC > Platelet | Numbers per μl: RBC > Platelets > WBC
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
