Review of Normal Gross Anatomy and Histology of the Respiratory System Flashcards
What is the definition between upper and lower airways?
Upper airways are extrathoracic -> go all the way to the superior part of the trachea
Lower airways are everything below. Becomes intrapulmonary airways after branching into left and right main pulmonary bronchi
In what way are the lungs like the liver?
They have a dual blood supply, with a smaller, well-oxygenated circulation and a large, poorly-oxygenated circulation
Large - pulmonary arteries (like portal vein)
Small - bronchial arteries - arising from aorta on left and internal thoracic artery on right (like hepatic artery)
How do you tell pulmonary artery vs bronchial artery vs pulmonary veins?
Pulmonary artery - about the same size as the bronchioles they travel with (adjacent to)
Bronchial artery - also travels adjacent to, but is much smaller than bronchioles and pulmonary arteries
Pulmonary veins - empty alveolar capillaries, run in the interlobular septae and subpleural connective tissue rather than near airways
Where do lymphatics run in the lungs?
Everywhere, because we really need to keep the lung dry
Includes adjacent to airways, within interlobular septa, and in the subpleural connective tissue
What do the hilum of the lungs contain? How do these nodes drain?
Largest airways and blood vessels, as well as hilar lymph nodes (which drain to subcarinal, mediastinal, and supraclavicular nodes, before finally communicating with venous circulation via thoracic duct)
What two structures does the left lung contain relating to the heart?
Both in the upper lobe
- Cardiac notch - lateral deflection of border
- Lingula
How many bronchopulmonary segments are there in the right and left lungs?
Right - 10 segments
Left - 8 segments
What is a primary pulmonary lobule?
An acinus - unit of lung supplied by one respiratory bronchiole
What is a secondary pulmonary lobule?
Larger than a primary. It is a unit of lung supplied by a single bronchiole which gives rise to 3-5 terminal bronchioles, and is surrounded by a single interlobular septum which is continuous with alveolar septae, peribronchovascular interstitium, and subpleural connective tissue
Where do the pleural surfaces reflect?
At the root of the lung (lateral mediastinum)
Otherwise they are separated by the pleural cavity
What are the fissures of each lung and how are they formed?
Right lung - horizontal (superior and middle) and oblique fissures (middle and inferior)
Left lung - Oblique (superior and inferior)
Formed as invaginations of the VISCERAL pleura
What are the four layers of the tracheal wall?
- Mucosa
- Submucosal (with glands)
- Cartilage / fibromuscular layer separating adjacent rings and on posterior side
- Adventitia - LCT / vessels
What populates the mucosa of the trachea and how is it different than a bronchus?
- Tall, pseudostratified columnar epithelium with goblet cells
- Lamina propria connective tissue with blood vessels (to warm the air)
Difference from bronchus - no muscularis mucosae, since the cartilage is so strong
What is the purpose of the submucosal glands in the upper airway?
Serous - warms / humidifies air
Mucinous - cleaning / clearing airway with mucociliary elevator
What bridges the posterior wall of the trachea?
A transverse band of smooth muscle called the trachealis muscle, as well as fibroelastic connective tissue
