The LRT Flashcards
Components of LRT
- Larynx
- Trachea
- Bronchi
- Bronchioles
- Alveoli
Functions of LRT
- Conducts air to/from the
site of gas exchange - Completes cleaning,
warming and humidifying
of air - Provides a barrier between
the air and blood, and a
large surface area for gas
exchange
Features of the larynx
- Passage of air only
- Anterior to esophagus
- From the hyoid bone to the trachea.
- Cartilages protect and maintain an open airway (patent)
- Epiglottis closes over the airway when swallow
What is the largest cartilage around the larynx
The thyroid cartilage
What is the cricoid cartilage
A solid ring of cartilage that goes around the entire tube
How is the adams apple formed
In biological males, the cartilage grows thicker and becomes more prominent at the laryngeal prominence
How many folds
*Vestibular folds
*Vocal folds
What are the vocal folds?
- ‘True’ vocal cords
- Passing air causes vibrations =
sound waves - Used for normal phonation
- Testosterone affects cartilage
and muscle, resulting in longer folds
thicker cartilage = deeper voice
What is the Glottis
The voice box
Vestibular folds
’False’ vocal cords
* Superior to vocal folds
* Prevent foreign object entry to
glottis
* Can produce very deep sounds
Where is the trachaea
- Anterior to esophagus
- Between the larynx and primary
bronchi
Features of the trachaea
- Maintain patent airway
- C-shaped cartilage rings
- Ends connected by a band of
smooth muscle: trachealis - Contracts for coughing
- Many elastin fibres in lamina
propria & submucosa - Clean, warm, humidify air
- Respiratory epithelium
What forms the mucus glands
A bunch of goblet cells
What does coughing do?
Removes the debris from the trachaea and puts it in the esophagus
What does the mucociliary escalator do?
*removes
debris to the pharynx,
to be swallowed and
digested
* Mucus from goblet
cells and mucous
glands coat surface
of epithelium
* Debris becomes
trapped
* Cilia move mucus to
pharynx
What is the hilum?
Where the bronchi and blood vessels branch into
Why is the base of the lungs curved?
Due to the diaphragm
Why does the left lung have only two lobes?
Due to the heart taking up space
What is the grooves in between where the heart sits in the left lung
Cardiac notch
What is the curved shape of the base of the lungs aks
Dome shaped
What is the costal surface?
The lateral surface of the lungs that comes into contact with the ribs
What does the trachaea branch into?
The bronchiole tree
Pathway of branching
Trachaea –> 1º bronchii –> 2º bronchii (lobar) –> 3º bronchii (segmental) –> bronchioles –> terminal bronchioles –> Alveoli
Features of the trachaea
- Trachea
- Respiratory epithelium
- C-shaped cartilage rings
- Trachealis muscle at posterior
Features of the 1º bronchii
- 1o bronchi
- Respiratory epithelium
- Cartilage and smooth muscle rings
complete
Features of the 2º and 3º bronchii
- 2o & 3o bronchi
- Respiratory epithelium starts to
decrease in height, goblet cell
numbers reduce - Cartilage plates
bronchioles
- Bronchioles <1mm
- Cuboidal epithelium
- No cartilage but thick smooth muscle
for bronchoconstriction/dilation
Terminal bronchioles <0.5mm
- Each supplies a pulmonary lobule
Features of the respiratory zone
- Pulmonary lobules made of
many alveoli (air sacs)
arranged like bunches of
grapes - ~150 million alveoli per lung
- Most of lung volume
- Enormous surface area
- Alveolar walls very thin:
simple squamous epithelium
on a thin basement
membrane - External surface of alveoli
covered in fine network of
pulmonary capillaries
How is GE made possible
Thin wall of the endotheleum of the caps and the think walls of the epitheleum of the alveoli
What are the cells of the alveoli
Pneumocytes (lung epithelial
cells)
2 types of Pneumocytes
- Type I squamous
- Type II cuboidal
Type 1 squamous
- Forms the respiratory
membrane/blood-air barrier
with capillary wall and shared
basement membrane
Type II cuboidal
- Scattered amongst Type I
- Secrete surfactant, a complex
lipoprotein (phospholipid) that
reduces the surface tension of
the alveolar fluid
