What is the process of respiratory system moves air into and out lungs?

The process of the respiratory system moving air into and out of the lungs is called _breathing_and is facilitated by the coordinated functions of the respiratory muscles, the diaphragm and the lungs.

1. Inspiration (inhalation):

- The diaphragm and the intercostal muscles contract. The diaphragm moves downwards, while the intercostal muscles pull the ribcage upwards and outwards.

- This expansion of the thoracic cavity creates a negative pressure within the chest.

- As a result, air is drawn in through the nose or mouth and travels down the trachea and into the lungs.

- The lungs expand as the air fills the alveoli (tiny air sacs within the lungs).

2. Expiration (exhalation)

- The diaphragm and the intercostal muscles relax. The diaphragm moves upwards, while the intercostal muscles allow the ribcage to move downwards and inwards.

- This reduction in the volume of the thoracic cavity creates a positive pressure within the chest.

- As a result, the air is pushed out of the lungs through the nose or mouth.

The respiratory rate, or the number of breaths taken per minute, is regulated by the respiratory center in the brain stem. Factors such as physical activity,情绪和血液中的二氧化碳水平can influence the respiratory rate.