Free Respiration MCQs with Answers
446 Respiration MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The human respiratory system includes the air passages, lungs, alveoli and breathing muscles, while gaseous exchange explains how oxygen enters blood and carbon dioxide leaves it by diffusion. The effects of smoking include damage to cilia and alveoli, reduced gas exchange, chronic bronchitis, emphysema and increased risk of lung cancer.
Last updated
Read the Respiration notesFree MDCAT chapter notes with key terms446 questions · page 5 of 23
- A. cockroach
- B. frog
- C. fish
- D. birds
Explanation: Parabronchi are the fine respiratory passages in bird lungs, where air flows continuously and gas exchange occurs through surrounding air…
Correct answer: birds- A. Larynx
- B. Pharynx
- C. Golttis
- D. None of these
Explanation: The vocal cords are stretched across the glottis, which is the opening of the larynx through which air passes.
Correct answer: Golttis- A. 10
- B. 3
- C. 4
- D. 9
Explanation: Most birds have nine air sacs: cervical, clavicular, anterior thoracic, posterior thoracic and abdominal sacs.
Correct answer: 9- A. Single
- B. Both
- C. Do not have opening
- D. None of these
Explanation: Parabronchi are the fine respiratory tubes in bird lungs, and they are open at both ends.
Correct answer: Both- A. Less than 7 month
- B. Less than 8 month
- C. Less than 9 month
- D. More than 9 month
Explanation: Respiratory distress syndrome is especially common in very premature infants, particularly those born before about seven months of…
Correct answer: Less than 7 month- A. Cuticular
- B. Cutaneous
- C. Skin
- D. Pulmonary
Explanation: Gaseous exchange through the skin is called cutaneous respiration. Oxygen diffuses through the moist skin into blood and carbon dioxide…
Correct answer: Cutaneous- A. Larynx
- B. Trachea
- C. Bronchi
- D. Bronchioles
Explanation: The trachea, bronchi and larynx contain cartilage that keeps their air passages open.
Correct answer: Bronchioles- A. Buccal cavity
- B. Pharynx
- C. Larynx
- D. Chest Cavity
Explanation: The larynx is called the voice box because it contains the vocal cords, which vibrate as air passes between them.
Correct answer: Larynx- A. Cockroach
- B. Earthworm
- C. Aves
- D. Frogs
Explanation: Birds have a unidirectional respiratory system in which air sacs drive air through the parabronchi during both inhalation and exhalation.
Correct answer: Aves- A. 2
- B. 3
- C. 6
- D. 8
Explanation: When the cockroach abdomen expands during inspiration, the eight abdominal pairs of spiracles open to admit air.
Correct answer: 8- A. 15
- B. 10
- C. 20
- D. 30
Explanation: Cockroaches possess 10 pairs of spiracles, two pairs on the thorax and eight pairs on the abdomen.
Correct answer: 20- A. 54 ml
- B. 60 ml
- C. 64 ml
- D. 50 ml
Explanation: Arterial blood carries about 48 ml of carbon dioxide per 100 ml of blood, commonly rounded to 50 ml per 100 ml in textbook questions.
Correct answer: 50 ml- A. 5%
- B. 70%
- C. 20%
- D. 10%
Explanation: About 20% to 23% of transported carbon dioxide forms carbaminohaemoglobin by binding to haemoglobin, so 20% is the suitable option.
Correct answer: 20%94. The increase in pH of blood has ________ effect on the oxygen carrying capacity of haemogolobin?
- A. plus ve
- B. - ve
- C. No
- D. All of these
Explanation: An increase in blood pH increases haemoglobin's affinity for oxygen, so its oxygen-carrying capacity rises.
Correct answer: plus ve- A. Temperature
- B. Carbon dioxide
- C. pH
- D. All of these
Explanation: Temperature, carbon dioxide concentration and pH all affect haemoglobin's affinity for oxygen.
Correct answer: All of these- A. 10 mm
- B. 60 mm
- C. 10 cm
- D. 100 mm
Explanation: At an oxygen partial pressure of about 100 mm Hg, haemoglobin is almost completely saturated because the oxygen-haemoglobin dissociation…
Correct answer: 100 mm- A. 10 ml
- B. 20 ml
- C. 30 ml
- D. 40 ml
Explanation: Each 100 ml of normal arterial blood carries about 20 ml of oxygen, mainly bound to haemoglobin and a small amount dissolved in plasma.
Correct answer: 20 ml- A. 16-30
- B. 15-20
- C. 5?10
- D. 6?12
Explanation: A resting human normally breathes about 15 to 20 times per minute, with the rhythm controlled by respiratory centres in the brain in…
Correct answer: 15-20- A. Disphragm
- B. Pleura
- C. Pericardium
- D. Rib cage
Explanation: The lungs are enclosed by the pleura, a double-layered membrane with a thin fluid-filled space that reduces friction during breathing.
Correct answer: Pleura- A. Air sacs
- B. Alveoli
- C. Bronchioles
- D. Parabronchi
Explanation: The lungs are spongy because they contain millions of alveoli, tiny air sacs surrounded by capillaries that provide a large surface area…
Correct answer: Alveoli