Question

To generate a pressure gradient to facilitate expiration and inspiration, the human body used the intercostal muscles and
A. Alveolar sacs
B. Bronchi
C. Primary, secondary and tertiary bronchioles
D. Diaphragm

Answer 1

Hint: Intercostal muscles are involved in the mechanism of breathing so does the diaphragm. Diaphragms are present at the base of the chest. It contracts and relaxes as we inhale and exhale.

Complete Answer:
- Resistance to airflow is caused by respiratory airways during inhalation and exhalation. The pressure gradient is required for the transportation of the air from the mouth (or nose) to pulmonary alveoli.
- Aerosol transport in the human lungs can help us to determine the health hazard of harmful particles. It is important to understand the breathing mechanism to prevent diseases related to respiration and also to determine the method for treatment that can help to cure these diseases of respiration or respiratory system.
- Intercostals muscles play a vital role in the process of respiration. Due to the difference between alveolar and atmospheric pressure the pressure gradient is generated (in the oral or nasal cavity is assumed atmospheric pressure). Intercostal muscles help in expanding and shrinking the size of the chest cavity to facilitate breathing.

Intercostal muscles are basically of 3 types:
1. External intercostals muscles
2. Internal intercostals muscles
3. Innermost intercostals muscles

During the process of inspiration, the diaphragm is contracted and pulls downward whilst the muscles between the ribs contract and pull upward. The diaphragm is relaxed during expiration, and there is a decrease in the volume of the thoracic cavity, while the pressure inside it increases. It results that the lungs contract and the air is forced outside of the body through the nose and mouth.

Hence option D is right. The human body used the intercostal muscles and diaphragm to generate a pressure gradient to facilitate expiration and inspiration.

Note: Diaphragm plays a vital role in respiration; damage can cause serious illnesses and lifetime pain. The pressure gradient is required for the transportation of the air from the mouth (or nose) to pulmonary alveoli. Aerosol transport in the human lungs can help us to determine the health hazard of harmful particles. It is important to understand the breathing mechanism to prevent the diseases related to respiration and also to determine the method for treatment that can help to cure these diseases of respiration or respiratory system.