Online Test — Breathing and Exchange of Gases
15 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 15
Taking in oxygen-rich air and giving out CO₂-rich air is called:
Digestion
Breathing
Circulation
Excretion
Explanation: Breathing (ventilation) is the exchange of air with the environment.
Question 2 of 15
The windpipe is also called the:
Larynx
Trachea
Pharynx
Bronchus
Explanation: The trachea is the windpipe.
Question 3 of 15
The dome-shaped muscle that helps in breathing is the:
Diaphragm
Biceps
Heart
Stomach
Explanation: The diaphragm separates the chest from the abdomen and aids breathing.
Question 4 of 15
Gas exchange in the lungs takes place in the:
Trachea
Alveoli
Larynx
Pharynx
Explanation: The alveoli are the site of gas exchange.
Question 5 of 15
The trachea is kept open by rings of:
Bone
Cartilage
Muscle only
Fat
Explanation: C-shaped cartilage rings keep the trachea open.
Question 6 of 15
During inspiration, the chest cavity:
Enlarges
Shrinks
Stays the same
Collapses
Explanation: The chest cavity enlarges during inspiration, lowering pressure.
Question 7 of 15
Gases move between alveoli and blood by:
Active transport
Diffusion
Osmosis
Filtration
Explanation: Gases diffuse from higher to lower partial pressure.
Question 8 of 15
Most oxygen in the blood is carried by:
Plasma
Haemoglobin
Platelets
White cells
Explanation: About 97% of oxygen binds haemoglobin as oxyhaemoglobin.
Question 9 of 15
Oxygen combined with haemoglobin is called:
Carbaminohaemoglobin
Oxyhaemoglobin
Methaemoglobin
Bicarbonate
Explanation: Oxygen + haemoglobin = oxyhaemoglobin.
Question 10 of 15
Most carbon dioxide is transported as:
Oxyhaemoglobin
Bicarbonate ions
Free bubbles
Glucose
Explanation: About 70% of CO₂ travels as bicarbonate ions in the plasma.
Question 11 of 15
In the tissues, oxyhaemoglobin tends to:
Release oxygen
Pick up more oxygen
Release carbon dioxide only
Do nothing
Explanation: Where oxygen is low (tissues), haemoglobin releases its oxygen.
Question 12 of 15
A disorder with narrowed, swollen airways and wheezing is:
Asthma
Jaundice
Anaemia
Diabetes
Explanation: Asthma narrows and inflames the airways.
Question 13 of 15
Damage to the alveolar walls, often from smoking, is:
Emphysema
Asthma
Pneumonia
Bronchitis
Explanation: Emphysema is breakdown of alveolar walls due to smoking.
Question 14 of 15
Silicosis and asbestosis are examples of:
Occupational lung diseases
Heart diseases
Skin diseases
Eye diseases
Explanation: They are occupational lung diseases from inhaling harmful dust.
Question 15 of 15
The single biggest avoidable cause of lung damage is:
Drinking water
Smoking
Exercise
Sleeping
Explanation: Smoking is the leading avoidable cause of lung damage and cancer.