Respiratory System — Set 1
Biology · श्वसन तंत्र · Questions 1–10 of 50
Which structure in the human respiratory system is commonly known as the 'Voice Box'?
Correct Answer: C. Larynx
The larynx contains the vocal cords which vibrate to produce sound. It is located between the pharynx and the trachea. This organ also protects the lower airways by closing during swallowing.
What is the primary site of gaseous exchange in the human lungs?
Correct Answer: A. Alveoli
Alveoli are tiny air sacs where oxygen enters the blood and carbon dioxide leaves it. They provide a massive surface area to maximize the efficiency of gas diffusion. A network of thin capillaries surrounds each alveolus to facilitate this process.
Which pigment in the blood is responsible for transporting the majority of oxygen?
Correct Answer: A. Hemoglobin
Hemoglobin is an iron-rich protein found in red blood cells that binds with oxygen. It carries oxygen from the lungs to the various tissues of the body. This pigment also gives blood its characteristic red color.
The muscular partition that separates the thoracic cavity from the abdominal cavity is called the?
Correct Answer: B. Diaphragm
The diaphragm is a dome-shaped muscle that is essential for the mechanics of breathing. It contracts and flattens during inhalation to increase the volume of the chest cavity. This movement creates a vacuum that pulls air into the lungs.
What prevents food from entering the windpipe during swallowing?
Correct Answer: B. Epiglottis
The epiglottis is a leaf-shaped flap of cartilage that covers the opening of the larynx. It ensures that food and liquids are directed into the esophagus rather than the trachea. If this mechanism fails, it can lead to choking or aspiration.
Which of the following describes the process of 'Internal Respiration'?
Correct Answer: C. Exchange of gases between blood and tissues
Internal respiration refers to the gas exchange occurring at the cellular level within body tissues. Oxygen diffuses out of the blood into cells while carbon dioxide moves from cells into the blood. This is distinct from external respiration, which occurs in the lungs.
What is the normal breathing rate for a healthy adult at rest?
Correct Answer: A. 12-16 times per minute
The average resting respiratory rate for an adult is generally between 12 and 16 breaths per minute. This rate can increase significantly during physical exercise or emotional stress. It is controlled automatically by the respiratory center in the brain.
The double-layered membrane that surrounds and protects the lungs is known as the?
Correct Answer: C. Pleura
The pleura consists of two layers with a thin fluid-filled space between them to reduce friction. This membrane allows the lungs to expand and contract smoothly against the chest wall. Inflammation of this membrane is a condition known as pleurisy.
Which gas acts as the primary chemical stimulus for the brain to regulate breathing?
Correct Answer: C. Carbon dioxide
The brain monitors the levels of carbon dioxide and the resulting pH change in the blood. High levels of carbon dioxide trigger the urge to breathe faster to expel the excess gas. Interestingly, the body is more sensitive to carbon dioxide buildup than to oxygen lack.
The maximum volume of air a person can exhale after a maximum inhalation is called?
Correct Answer: A. Vital Capacity
Vital capacity is the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume. It represents the total amount of air that can be moved in and out through conscious effort. This measurement is often used to assess the functional state of the lungs.