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3.4 Control of Respiration — Test 1
Q1. The urge to inhale in humans results mainly from a:✓ Rising level of arterial PCO₂
Q2. The main respiratory centre that sets the basic rhythm of breathing is located in the:✓ Medulla oblongata
Q3. Respiratory alkalosis is caused by:✓ Decreased H₂CO₃ from blowing off too much CO₂
Q4. Which of the following is NOT an effector (muscle) of breathing?✓ Trapezius muscle (a postural muscle)
Q5. The peripheral chemoreceptors that detect low blood oxygen are the:✓ Type-I (glomus) cells of the carotid and aortic bodies
Q6. Breathing can be held voluntarily only up to the 'breaking point', which is reached mainly because of:✓ Rising CO₂ (and falling O₂) forcing the respiratory centre to act
Q7. Transection of the spinal cord at the C1–C2 level stops breathing because it cuts off the:✓ Phrenic nerve supply to the diaphragm
Q8. The Hering–Breuer reflex helps prevent over-inflation of the lungs by responding to:✓ Stretch receptors in the lung tissue
Q9. The central chemoreceptors that drive breathing are most sensitive to changes in:✓ The H⁺/CO₂ level of the cerebrospinal fluid
Q10. Abnormal breathing rhythm most often results from malfunction of the:✓ Brainstem (medulla and pons)
Q11. During exercise, ventilation increases mainly in response to:✓ Increased CO₂ production and neural drive from active muscles
Q12. The chief excretory route for the gaseous waste carbon dioxide is the:✓ Lungs
Q13. Hypoxia means:✓ A deficiency of oxygen reaching the tissues
Q14. Asphyxia (suffocation) leads to a combination of:✓ Hypoxia (low O₂) and hypercapnia (high CO₂)
Q15. The apneustic and pneumotaxic centres that modify breathing are located in the:✓ Pons
Q16. A rise in blood CO₂ (hypercapnia) generally causes:✓ An increase in the rate and depth of breathing