二次小葉
- 英
- secondary lobule
- 同
- 小葉
- 関
- 一次小葉 = 細葉
- 小葉間隔壁が5個程度の細葉を内包して二次小葉(小葉)となる (SRA.206) → Millerの二次小葉
- 放射線学的最小単位(1-2cm)であり、数個の細葉(=一次小葉)から構成される。二次小葉の境界は小葉間結合組織で区切られている。
Secondary lobule Knowledge of the lung anatomy is essential for understanding HRCT. The secondary lobule is the basic anatomic unit of pulmonary structure and function. Interpretation of interstitial lung diseases is based on the type of involvement of the secondary lobule. It is the smallest lung unit that is surrounded by connective tissue septa. It measures about 1-2 cm and is made up of 5-15 pulmonary acini, that contain the alveoli for gas exchange. The secondary lobule is supplied by a small bronchiole (terminal bronchiole) in the center, that is parallelled by the centrilobular artery. Pulmonary veins and lymphatics run in the periphery of the lobule within the interlobular septa. Under normal conditions only a few of these very thin septa will be seen. There are two lymphatic systems: a central network, that runs along the bronchovascular bundle towards the centre of the lobule and a peripheral network, that is located within the interlobular septa and along the pleural linings.