Lower Respiratory Tract Flashcards
What are the main components of the lower respiratory tract?
Trachea
Main stem of bronchi
Bronchial tubes
Lungs (alveoli)
What type of epithelium lines the trachea, bronchi, and bronchial tubes?
What are these structures contained in?
Pseudostratified columnar ciliated epithelium
Contained in a mucous membrane
What is the purpose of the cilia on the pseudostratified columnar ciliated epithelium lining the lower respiratory tract?
Cilia move a layer of mucous toward the laryngopharynx where it can be swallowed or coughed up
What midline structure is continuous with the larynx from the neck into the superior mediastinum?
Trachea
The trachea extends from _____ vertebrae to the ______ angle (the junction of the manubrium to the sternal body) at the same level as ______
C6
Sternal
T4
The ________ _________ plane passes through the sternal angle to intersect the intervertebral disc between the T4-T5 verebrae. This plane intersects the trachea in the midline where it bifurcates into 2 main bronchi.
Transverse thoracic
Describe the diameter and length of the trachea in adults
3/4” diameter
3.5-5” long
Describe the composition of the trachea
20 U-shaped hyaline cartilage rings
Smooth muscle - found in elastic posterior wall next to esophagus
Mucous glands - keep surface of epithelium coated
What arteries supply the trachea?
Superior and inferior thyroid aa.
What veins drain the trachea?
Superior, middle, and inferior thyroid veins
Compare/contrast the right main bronchus with the left main bronchus
Right main bronchus:
Larger diameter
More vertical
Shorter length
Left main bronchus:
Smaller diameter
Less vertical
Longer length
The secondary (lobar) bronchi go to the lobes of the lungs. Describe the lobar bronchi in the right vs. left lung
Right lung = 3 lobar bronchi (because 3 lobes)
Left lung = 2 lobar bronchi (because 2 lobes)
The _________ ___________ refer to the largest subdivisions of a lobe of a lung. They are pyramidal shaped segments with their apices facing the lung root and their bases at the pleural surface.
Bronchopulmonary segments
The bronchopulmonary segments refer to the largest subdivisions of a lobe of a lung. They are pyramidal shaped segments with their apices facing the lung root and their bases at the pleural surface.
They are separated from adjacent segments by connective tissue ________.
They are supplied independently by a __________ bronchus and tertiary branch of a _________ artery
Septa
Segmental; pulmonary
Bronchopulmonary segments are named according to segmental bronchi supplying them. They are supplied independently by a segmental bronchus and a tertiary branch of a pulmonary artery. What drains the bronchopulmonary segments?
Intersegmental parts of pulmonary veins that lie in connective tissue between and drain adjacent segments
What do the tertiary (segmental) bronchi supply?
The bronchopulmonary segments - which are the largest subdivisions of a lobe (pyramidal shaped segments of the lung with their apices facing the lung root and their bases at the pleural surface)
How many segments/segmental bronchi are associated with each lung?
Right lung = 10 segments, 10 segmental bronchi
Left lung = 8 segments, 8 segmental bronchi
What is the next level of branching below the tertiary (segmental) bronchi?
Beyond tertiary segmental bonchi, there are 20-25 generations of branching conducting bronchioles that eventually end as terminal bronchioles
What are the overall levels of branching of the lower respiratory tract from the trachea to the alveoli?
Trachea Primary/main bronchi Secondary/lobar bronchi Tertiary/segmental bronchi Terminal bronchioles Respiratory bronchioles Alveoli
What are the smallest conducting bronchioles? Describe their characteristics
Terminal bronchioles
Lack cartilage in their walls
Transport air but lack glands or alveoli
Give rise to respiratory bronchioles
In which division of the lower respiratory tract do alveoli first appear?
Respiratory bronchioles
Respiratory bronchioles are characterized by scattered, thin walled outpocketings called ______ that extend from their lumens.
Alveoli
What are the 2 primary functions of respiratory bronchioles?
Transport air
Gas exchange
Each respiratory bronchiole gives rise to 2-11 _______ _______
Alveolar ducts
Each respiratory bronchiole gives rise to 2-11 alveolar ducts
Each alveolar duct gives rise to 5-6 ______ _______, into which clusters of alveoli open
Alveolar sacs
Alveoli have a ______ ______ thickness
They are organized in ________ and are surrounded by a dense _______ network
Single-celled
Clusters; capillary
What arteries supply the bronchi but not the alveoli?
3 bronchial arteries (2 left, 1 right)
[these supply the bronchial tubes but not the alveoli because they are not part of pulmonary circulation]
The 3 bronchial arteries (2 left and 1 right) are responsible for supplying the bronchial tubes. What do these branch from?
The descending aorta
Describe venous drainage of the bronchi
Bronchial veins drain to the azygous veins, which are tributaries to the superior vena cava
What general structures are associated with the surface anatomy of the lungs?
Fissures Cardiac notch Lingula Apex Base Hilum Visceral pleura