When the lungs inhale, the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs.

What is the sequence for inspiration?

Inspiratory muscles contract (diaphragm descends; rib cage rises). Thoracic cavity volume increases. Lungs are stretched;intrapulmonary volume increases.

What are the sequence of events for inspiration and expiration?

Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages). Elastic lungs recoil passively; intrapulmonary volume decreases. Intrapulmonary pressure rises (to +1 mm Hg). Air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0.

Which of the following sequence is correct to initiate inspiration?

(i) The contraction of external intercostal muscles raises the ribs and sternum. (ii) Volume of thorax increases in the dorso-ventral axis. (iii) Intrapulmonary pressure decreases. (iv) Diaphragm contraction.

Which of the following is correct during inspiration process?

Hence, Option A) During inspiration external intercostal muscles and diaphragm contract is the correct answer. Note: We breathe by inhaling through our nose and exhaling through our mouth.

What are the events of inspiration?

The first phase is called inspiration, or inhaling. When the lungs inhale, the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside.

Why is inspiration an active process?

Inspiration is an active process whereas expiration is a passive process. Inspiration occurs when the muscles of the diaphragm contract to increase the overall volume of the thoracic cavity. As the muscles use energy for contraction, inspiration is called active process.

Which of the following is part of inspiration?

Inspiration (inhalation) is the process of taking air into the lungs. It is the active phase of ventilation because it is the result of muscle contraction. During inspiration, the diaphragm contracts and the thoracic cavity increases in volume. This decreases the intraalveolar pressure so that air flows into the lungs.

Which of the following is the correct sequence of events for an inhalation?

Nostrils → nasal cavity →Pharynx → Larynx →Trachea → Bronchi → Bronchioles → Alveoli or air sacs. Therefore, out of the given options, option D ‘Nostrils —> pharynx —> larynx —> trachea —> alveoli’ is the most appropriate option.

Which muscle’s contraction will stimulate inspiration?

The most important muscle of inspiration is the diaphragm; however, the external intercostals assist with normal quiet breathing. Contraction of the diaphragm increases the space in the thoracic cavity and the lungs fill with air from the external environment.

What are the two major steps of breathing?

Breathing (or pulmonary ventilation) has two phases – inspiration (or inhalation) and expiration (or exhalation). It is a mechanical process that depends on volume changes in the chest cavity. The volume changes result in pressure changes, which lead to the flow of gases to equalise the pressure.

Which of the following changes occur in diaphragm and intercostal?

When the internal intercostal muscles contract and diaphragm relax, the ribs move downward and inward and diaphragm becomes, convex (dome shaped), thus decreasing the volume of thoracic cavity and increasing the pressure inside as compared to the atmospheric pressure outside.

Is expiration active or passive?

The Process of Expiration Expiration is typically a passive process that happens from the relaxation of the diaphragm muscle (that contracted during inspiration). The primary reason that expiration is passive is due to the elastic recoil of the lungs.

Which of the following is not associated with inspiration?

The pectoralis major (answer C) muscle is not used for inspiration.

Which of the following events occurs during expiration?

During expiration, the diaphragm and intercostals relax, causing the thorax and lungs to recoil. The air pressure within the lungs increases to above the pressure of the atmosphere, causing air to be forced out of the lungs.

Which of the following events occur in pulmonary capillary?

There are five main diffusion events that take place during the process of red blood cell oxygenation within the pulmonary capillaries. The third diffusion event is the convection and diffusion of oxygen to the red blood cell within the pulmonary capillaries.