Alveolar duct
Closely spaced alveoli forming the wall of alveolar ducts are separated by thin interalveolar septa capped by knobs containing smooth muscle. The smooth muscle forms a sphincter-like ring around the opening of each alveolus and is lined by a simple cuboidal epithelium, without cilia or club cells. The interalveolar septum possesses numerous capillaries where gas exchange occurs. 800x
Alveoli
Closely spaced alveoli forming the wall of alveolar ducts are separated by thin interalveolar septa capped by knobs containing smooth muscle. The smooth muscle forms a sphincter-like ring around the opening of each alveolus and is lined by a simple cuboidal epithelium, without cilia or club cells. The interalveolar septum possesses numerous capillaries where gas exchange occurs. 800x
Interalveolar septa
Closely spaced alveoli forming the wall of alveolar ducts are separated by thin interalveolar septa capped by knobs containing smooth muscle. The smooth muscle forms a sphincter-like ring around the opening of each alveolus and is lined by a simple cuboidal epithelium, without cilia or club cells. The interalveolar septum possesses numerous capillaries where gas exchange occurs. 800x
- Knobs
Closely spaced alveoli forming the wall of alveolar ducts are separated by thin interalveolar septa capped by knobs containing smooth muscle. The smooth muscle forms a sphincter-like ring around the opening of each alveolus and is lined by a simple cuboidal epithelium, without cilia or club cells. The interalveolar septum possesses numerous capillaries where gas exchange occurs. 800x
- Epithelium
Closely spaced alveoli forming the wall of alveolar ducts are separated by thin interalveolar septa capped by knobs containing smooth muscle. The smooth muscle forms a sphincter-like ring around the opening of each alveolus and is lined by a simple cuboidal epithelium, without cilia or club cells. The interalveolar septum possesses numerous capillaries where gas exchange occurs. 800x
- Smooth muscle
Closely spaced alveoli forming the wall of alveolar ducts are separated by thin interalveolar septa capped by knobs containing smooth muscle. The smooth muscle forms a sphincter-like ring around the opening of each alveolus and is lined by a simple cuboidal epithelium, without cilia or club cells. The interalveolar septum possesses numerous capillaries where gas exchange occurs. 800x
- Capillaries
Closely spaced alveoli forming the wall of alveolar ducts are separated by thin interalveolar septa capped by knobs containing smooth muscle. The smooth muscle forms a sphincter-like ring around the opening of each alveolus and is lined by a simple cuboidal epithelium, without cilia or club cells. The interalveolar septum possesses numerous capillaries where gas exchange occurs. 800x
Image source
The image was taken of a slide in the University of New England College of Osteopathic Medicine collection.