The LRT

Question 1

Components of LRT

Answer 1

• Larynx
• Trachea
• Bronchi
• Bronchioles
• Alveoli

Question 2

Functions of LRT

Answer 2

• 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

Question 3

Features of the larynx

Answer 3

• 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

Question 4

What is the largest cartilage around the larynx

Answer 4

The thyroid cartilage

Question 5

What is the cricoid cartilage

Answer 5

A solid ring of cartilage that goes around the entire tube

Question 6

How is the adams apple formed

Answer 6

In biological males, the cartilage grows thicker and becomes more prominent at the laryngeal prominence

Question 7

How many folds

Answer 7

*Vestibular folds
*Vocal folds

Question 8

What are the vocal folds?

Answer 8

• ‘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

Question 9

What is the Glottis

Answer 9

The voice box

Question 10

Vestibular folds

Answer 10

’False’ vocal cords
* Superior to vocal folds
* Prevent foreign object entry to
glottis
* Can produce very deep sounds

Question 11

Where is the trachaea

Answer 11

• Anterior to esophagus
• Between the larynx and primary
  bronchi

Question 12

Features of the trachaea

Answer 12

• 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

Question 13

What forms the mucus glands

Answer 13

A bunch of goblet cells

Question 14

What does coughing do?

Answer 14

Removes the debris from the trachaea and puts it in the esophagus

Question 15

What does the mucociliary escalator do?

Answer 15

*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

Question 16

What is the hilum?

Answer 16

Where the bronchi and blood vessels branch into

Question 17

Why is the base of the lungs curved?

Answer 17

Due to the diaphragm

Question 18

Why does the left lung have only two lobes?

Answer 18

Due to the heart taking up space

Question 19

What is the grooves in between where the heart sits in the left lung

Answer 19

Cardiac notch

Question 20

What is the curved shape of the base of the lungs aks

Answer 20

Dome shaped

Question 21

What is the costal surface?

Answer 21

The lateral surface of the lungs that comes into contact with the ribs

Question 22

What does the trachaea branch into?

Answer 22

The bronchiole tree

Question 23

Pathway of branching

Answer 23

Trachaea –> 1º bronchii –> 2º bronchii (lobar) –> 3º bronchii (segmental) –> bronchioles –> terminal bronchioles –> Alveoli

Question 24

Features of the trachaea

Answer 24

• Trachea
• Respiratory epithelium
• C-shaped cartilage rings
• Trachealis muscle at posterior

Question 25

Features of the 1º bronchii

Answer 25

* 1o bronchi * Respiratory epithelium * Cartilage and smooth muscle rings complete

Question 26

Features of the 2º and 3º bronchii

Answer 26

* 2o & 3o bronchi * Respiratory epithelium starts to decrease in height, goblet cell numbers reduce * Cartilage plates

Question 27

bronchioles

Answer 27

* Bronchioles <1mm * Cuboidal epithelium * No cartilage but thick smooth muscle for bronchoconstriction/dilation

Question 28

Terminal bronchioles <0.5mm

Answer 28

* Each supplies a pulmonary lobule

Question 29

Features of the respiratory zone

Answer 29

* 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

Question 30

How is GE made possible

Answer 30

Thin wall of the endotheleum of the caps and the think walls of the epitheleum of the alveoli

Question 31

What are the cells of the alveoli

Answer 31

Pneumocytes (lung epithelial cells)

Question 32

2 types of Pneumocytes

Answer 32

* Type I squamous * Type II cuboidal

Question 33

Type 1 squamous

Answer 33

* Forms the respiratory membrane/blood-air barrier with capillary wall and shared basement membrane

Question 34

Type II cuboidal

Answer 34

* Scattered amongst Type I * Secrete surfactant, a complex lipoprotein (phospholipid) that reduces the surface tension of the alveolar fluid