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Root of the lung
Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x
![Secondary bronchi <p>Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x </p>](https://digitalhistology.org/wp-content/uploads/2018/06/O.R.I.C.SB_.01.P01.png)
Secondary bronchi
Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x
![Cartilage plates <p>Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x </p>](https://digitalhistology.org/wp-content/uploads/2018/06/O.R.I.C.SB_.01.P02.png)
Cartilage plates
Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x
![Mixed glands <p>Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x </p>](https://digitalhistology.org/wp-content/uploads/2018/06/O.R.I.C.SB_.01.P03.png)
Mixed glands
Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x
![Pulmonary vessels <p>Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x </p>](https://digitalhistology.org/wp-content/uploads/2018/06/O.R.I.C.SB_.01.P04.png)
Pulmonary vessels
Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x
![Bronchioles <p>Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x </p>](https://digitalhistology.org/wp-content/uploads/2018/06/O.R.I.C.SB_.01.P05.png)
Bronchioles
Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x
![Alveoli <p>Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x </p>](https://digitalhistology.org/wp-content/uploads/2018/06/O.R.I.C.SB_.01.P06.png)
Alveoli
Upon entering the lungs, primary bronchi branch to form secondary bronchi. Large pulmonary arteries and veins lie adjacent to secondary bronchi, forming the root of the lung. In secondary bronchi, cartilage plates replace cartilage rings; mixed glands are still present. Millions of alveoli comprise the lung proper, so all intrapulmonary structures, like secondary bronchi, are surrounded by alveoli. When cut in sections, alveoli resemble tennis balls cut in half. 10x
![Image credit <p>This image was taken from The University of Michigan collection.</p>](https://digitalhistology.org/wp-content/uploads/2018/12/Michigan-source-ping-2.png)
Image credit
This image was taken from The University of Michigan collection.