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The trachea (pl.: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals lungs. The trachea extends from the larynx and branches into the two primary bronchi.
The carina is a cartilaginous ridge separating the left and right main bronchi that is formed by the inferior-ward and posterior-ward prolongation of the inferior-most tracheal cartilage.
The spiracles are located laterally along the thorax and abdomen of most insects—usually one pair of spiracles per body segment. Air flow is regulated by small muscles that operate one or two flap-like valves within each spiracle—contracting to close the spiracle, or relaxing to open it.
In humans and other mammals, the anatomy of a typical respiratory system is the respiratory tract.The tract is divided into an upper and a lower respiratory tract.The upper tract includes the nose, nasal cavities, sinuses, pharynx and the part of the larynx above the vocal folds.
In adult humans, the larynx is found in the anterior neck at the level of the cervical vertebrae C3–C6. It connects the inferior part of the pharynx (hypopharynx) with the trachea . The laryngeal skeleton consists of nine cartilages : three single ( epiglottic , thyroid and cricoid ) and three paired ( arytenoid , corniculate , and cuneiform ...
The mean number of alveoli in a human lung is 480 million. [11] When the diaphragm contracts, a negative pressure is generated in the thorax and air rushes in to fill the cavity. When that happens, these sacs fill with air, making the lung expand. The alveoli are rich with capillaries, called alveolar capillaries.
This article contains a list of organs in the human body. It is widely believed that there are 79 organs (this number goes up if you count each bone and muscle as an organ on their own, which is becoming a more common practice [1] [2]); however, there is no universal standard definition of what constitutes an organ, and some tissue groups' status as one is debated. [3]
The carina of the trachea is located at the level of the sternal angle and the fifth thoracic vertebra (at rest). The right main bronchus is wider, shorter, and more vertical than the left main bronchus, [ 3 ] its mean length is 1.09 cm. [ 4 ] It enters the root of the right lung at approximately the fifth thoracic vertebra.