Structure of the Lungs Flashcards
Describe the position, structure and function of the trachea
It starts at C6 and ends at T4/5 at carina. It is made of C-shaped rings of hyaline cartilage supporting a fibro-elastic and muscular tube.
It transports air from the larynx to the lungs.
Describe the difference between the two lungs
The Right lung has three lobes and the main bronchus is slightly more vertical, shorter and wider than the left. The left lung only has two lobes. There fore foreign bodies are more likely to enter the right lung because it’s more vertical
Name the lobar bronchus in the right lung
Right superior (eparterial) lobar bronchus, Right middle lobar bronchus and the Right lower lobar bronchus
Name the lobar bronchus of the left lung
Left superior lobar bronchus and the left inferior bronchus
Bronchi begin dividing into smaller branches, name these branches in order as they descend
Conducting bronchioles, then terminal bronchioles and finally respiratory bronchioles. They descend in diameter until finally becoming alveoli.
Describe the histology of the trachea
Pseudostratified, ciliated, columnar epithelium with goblet cells that secret mucus.
Describe the histology of bronchi
Still psudostratified, ciliated, columnar epithelium but the cells are shorter. C shaped cartilage replaced by cartilage plates as the bronchi branch into the lungs
Describe the histology of the bronchioles (conducting)
The epithelium changes to ciliated columnar and there is a sounding band of smooth muscle. Cartilage disappear and the bronchiole is held open by lung tissue.
What occurs in asthma?
The smooth muscle in the wall may contract and therefore narrow the luman. This can occur with the release of histamine.
Describe the histology of terminal and respiratory bronchiole
The epithelium becomes non-ciliated, cuboidal and goblet cells disappear.
Describe the histology of alveoli
Walls of alveoli are very think to allow for rapid diffusion but means they are also very susceptible to damage. Simple Squamous epithelium
What is the parietal pleura, the pleural cavity and the visceral pleura
The parietal pleura lines the cavity wall, the visceral pleura refers to the lining covering the lungs and the pleura cavity is the space between the serous membrane which contains fluid for the movement between surfaces.
Name the different areas of the parietal pleura
At the top is the cervical pleura, then the costal pleura, then there is the Diaphragmatic and mediastinal pleura.
What keeps the lung inflated?
The negative pressure in the pleura cavity
Describe the features of the left lung.
The left is slightly longer and narrower this is mostly to made room for the heart and pericardium. It has a superior and inferior lobe, a cardiac notch and the lingula.
