Respiratory System — Set 2
Biology · श्वसन तंत्र · Questions 11–20 of 50
In which part of the brain is the respiratory rhythm center located?
Correct Answer: B. Medulla oblongata
The medulla oblongata contains the primary control centers that maintain a steady breathing rhythm. It sends signals to the diaphragm and intercostal muscles to coordinate inhalation. Damage to this area can lead to immediate respiratory failure.
Which of the following is an occupational respiratory disorder?
Correct Answer: B. Silicosis
Silicosis is caused by the long-term inhalation of silica dust, common in mining and stone-cutting industries. It leads to the formation of fibrous tissue in the lungs, making breathing difficult. Such conditions are preventable by using proper protective gear in hazardous workplaces.
What happens to the rib cage during the process of expiration (exhalation)?
Correct Answer: A. It moves downwards and inwards
The correct answer is 'It moves downwards and inwards'. During exhalation, the external intercostal muscles relax, causing the ribs to move down and in. This decreases the volume of the thoracic cavity and increases the pressure inside the lungs. As a result, air is forced out of the respiratory tract.
Approximately what percentage of carbon dioxide is transported as bicarbonate ions in the blood?
Correct Answer: B. 70%
The majority of carbon dioxide produced by cells is converted into bicarbonate ions for efficient transport in plasma. This conversion is facilitated by the enzyme carbonic anhydrase found in red blood cells. A smaller portion is carried bound to hemoglobin or dissolved in plasma.
The C-shaped cartilaginous rings are found in which part of the respiratory tract?
Correct Answer: A. Trachea
The trachea or windpipe is reinforced with incomplete cartilage rings to prevent it from collapsing. These rings keep the airway open at all times regardless of air pressure changes. Their 'C' shape allows the esophagus behind it to expand during swallowing.
Which of the following conditions is characterized by the inflammation of the bronchial tubes?
Correct Answer: A. Bronchitis
Bronchitis involves the swelling of the lining of the bronchi, leading to coughing and mucus production. It can be acute, often following a cold, or chronic, typically caused by smoking. This inflammation narrows the airways, making it harder to move air into the lungs.
What is the volume of air inspired or expired during a normal breath called?
Correct Answer: C. Tidal Volume
Tidal volume is the amount of air moved in or out of the lungs during a quiet, relaxed breath. In a healthy adult, this volume is approximately 500 milliliters. It provides the necessary gas exchange for the body's baseline metabolic needs.
Carbon monoxide is dangerous because it has a much higher affinity for hemoglobin than oxygen. How many times higher is this affinity?
Correct Answer: C. 200-250 times
Hemoglobin binds with carbon monoxide about 200 to 250 times more strongly than it does with oxygen. This forms carboxyhemoglobin, which prevents oxygen from being carried to vital organs. Carbon monoxide is particularly hazardous because it is colorless and odorless.
Which of these structures is the first part of the 'Lower Respiratory Tract'?
Correct Answer: D. Larynx
The respiratory system is divided into upper and lower tracts, with the larynx serving as the entry to the lower part. The upper tract includes the nose, nasal cavity, and pharynx. This division is often used clinically to categorize various respiratory infections.
Where does the 'Trachea' divide into the right and left primary bronchi?
Correct Answer: B. At the level of the 5th thoracic vertebra
The windpipe branches into two tubes called bronchi at the level of the mid-chest. Each bronchus then enters its respective lung and divides further into smaller branches. This branching point is anatomically known as the carina.