Respiratory System — Set 5
Biology · श्वसन तंत्र · Questions 41–50 of 50
What is the percentage of Carbon Dioxide in the air we inhale?
Correct Answer: D. 0.04%
Normal atmospheric air contains about 0.04% carbon dioxide. After the body undergoes cellular respiration, the concentration of CO2 in exhaled air rises to about 4%. This increase reflects the body's disposal of metabolic waste.
Where is the 'Pneumotaxic Center' located in the brain?
Correct Answer: A. Pons
The pneumotaxic center is located in the pons region of the brainstem. It functions to moderate the signals from the respiratory rhythm center to prevent over-inflation of the lungs. It essentially helps in fine-tuning the breathing pattern.
In humans, which lung is slightly smaller to accommodate the heart?
Correct Answer: D. Left lung
The left lung is slightly smaller and has a notch called the cardiac notch where the heart sits. It is divided into only two lobes, whereas the right lung has three. This anatomical arrangement ensures optimal use of space in the thoracic cavity.
The primary role of 'Surfactant' in the alveoli is to?
Correct Answer: B. Prevent alveolar collapse
Surfactant is a lipid-rich fluid that reduces surface tension inside the alveoli. This makes it easier for the air sacs to expand and prevents them from sticking together when they deflate. Lack of surfactant in premature babies causes respiratory distress syndrome.
Which gas has the highest solubility in blood plasma?
Correct Answer: A. Carbon dioxide
Carbon dioxide is about 20-25 times more soluble in blood than oxygen is. This high solubility allows CO2 to be transported easily in dissolved form in the plasma. Solubility is a key factor in the diffusion of gases across respiratory membranes.
Which condition refers to a bluish discoloration of the skin due to poor oxygenation?
Correct Answer: D. Cyanosis
Cyanosis occurs when the blood is not carrying enough oxygen, making it appear darker or purplish. This color change is most visible in the lips, fingernails, and mucous membranes. it is a critical sign of respiratory or circulatory distress.
Which part of the pharynx is located directly behind the nasal cavity?
Correct Answer: A. Nasopharynx
The nasopharynx is the uppermost part of the pharynx and serves exclusively as a passage for air. It contains the openings of the Eustachian tubes, which connect to the middle ear. During swallowing, the soft palate moves up to close off this area.
What is the approximate surface area of the alveoli in an adult human?
Correct Answer: A. 70-100 square meters
The correct answer is '70-100 square meters'. The total surface area of all alveoli combined is roughly equivalent to the size of a tennis court. This vast area is necessary to ensure enough oxygen can be absorbed to support the body's high metabolic rate. The membrane at this site is extremely thin for fast diffusion.
Which structure connects the Pharynx to the Trachea?
Correct Answer: C. Larynx
The larynx is the intermediate structure that directs air from the throat into the windpipe. It is composed of several pieces of cartilage, the largest being the thyroid cartilage. It plays a dual role in sound production and airway protection.
Which process is also known as 'Gems' fact: Cellular Respiration?
Correct Answer: B. Breakdown of glucose with oxygen
Cellular respiration is the biochemical process where cells use oxygen to break down nutrients like glucose to produce ATP. Carbon dioxide and water are released as byproducts of this energy-releasing reaction. It takes place within the mitochondria of every living cell.