In the normal expiration, the diaphragm is –
A) Arched
B) Flattened
C) Not involved
D) Perforated
Answer
290.4k+ views
Hint:During the process of expiration, the intercostal muscles along with the diaphragm acquire their relaxed states. The diaphragm relaxes in order to decrease the volume of the thoracic chamber.
Complete Answer:
To understand this concept, we need to study the mechanism involved in breathing. There are two basic steps of this mechanism which are inspiration and expiration. Atmospheric air is drawn into the lungs during inspiration while in expiration, alveolar air is released outside. A pressure gradient is formed between the lungs and the environment in order to exchange gases. Inspiration occurs when the intrapulmonary pressure, i.e. the pressure inside lungs is less than that of the atmosphere. This produced a negative pressure inside the lungs with respect to the atmosphere. Similarly, when intrapulmonary pressure is higher than that of the atmosphere, expiration occurs as the pressure gradient inside the lungs is higher with respect with the environment. This change of gradient occurs due to activity of diaphragm and intercostal muscles, both internal as well as external intercostal muscles. For inspiration, diaphragm contracts and the external intercostal muscles lift up the ribs along with sternum due to contraction, thereby increasing the volume of the thoracic chamber in both antero-posterior and dorsi-ventral axes. This increases the pulmonary volume which decreases the intrapulmonary pressure and results in inspiration. The relaxation of intercostal muscles and diaphragm returns sternum to its normal position, decreasing the volume of the thoracic chamber which results in an increased intrapulmonary pressure, finally resulting in expiration.
Thus, the correct answer is option ‘A’. Arched.
Note:The contraction in muscles causes inspiration while their relaxation results in expiration. The diaphragm remains arched in its relaxed state while expands due to contraction.
Complete Answer:
To understand this concept, we need to study the mechanism involved in breathing. There are two basic steps of this mechanism which are inspiration and expiration. Atmospheric air is drawn into the lungs during inspiration while in expiration, alveolar air is released outside. A pressure gradient is formed between the lungs and the environment in order to exchange gases. Inspiration occurs when the intrapulmonary pressure, i.e. the pressure inside lungs is less than that of the atmosphere. This produced a negative pressure inside the lungs with respect to the atmosphere. Similarly, when intrapulmonary pressure is higher than that of the atmosphere, expiration occurs as the pressure gradient inside the lungs is higher with respect with the environment. This change of gradient occurs due to activity of diaphragm and intercostal muscles, both internal as well as external intercostal muscles. For inspiration, diaphragm contracts and the external intercostal muscles lift up the ribs along with sternum due to contraction, thereby increasing the volume of the thoracic chamber in both antero-posterior and dorsi-ventral axes. This increases the pulmonary volume which decreases the intrapulmonary pressure and results in inspiration. The relaxation of intercostal muscles and diaphragm returns sternum to its normal position, decreasing the volume of the thoracic chamber which results in an increased intrapulmonary pressure, finally resulting in expiration.
Thus, the correct answer is option ‘A’. Arched.
Note:The contraction in muscles causes inspiration while their relaxation results in expiration. The diaphragm remains arched in its relaxed state while expands due to contraction.

Last updated date: 01st Jun 2023
•
Total views: 290.4k
•
Views today: 2.46k
Recently Updated Pages
Most eubacterial antibiotics are obtained from A Rhizobium class 12 biology NEET_UG

Salamin bioinsecticides have been extracted from A class 12 biology NEET_UG

Which of the following statements regarding Baculoviruses class 12 biology NEET_UG

Sewage or municipal sewer pipes should not be directly class 12 biology NEET_UG

Sewage purification is performed by A Microbes B Fertilisers class 12 biology NEET_UG

Enzyme immobilisation is Aconversion of an active enzyme class 12 biology NEET_UG

Trending doubts
Difference Between Plant Cell and Animal Cell

Write an application to the principal requesting five class 10 english CBSE

Ray optics is valid when characteristic dimensions class 12 physics CBSE

Give 10 examples for herbs , shrubs , climbers , creepers

Write a letter to the principal requesting him to grant class 10 english CBSE

List out three methods of soil conservation

Epipetalous and syngenesious stamens occur in aSolanaceae class 11 biology CBSE

Change the following sentences into negative and interrogative class 10 english CBSE

A Short Paragraph on our Country India
