Intro to Respiratory System 2: Structures of lungs, bronchi and pleura

Question 1

What is the conducting zone ?

Answer 1

Nose, nasal cavity, sinuses
Nasopharynx and soft palate
Larynx
Trachea
Bronchi and bronchial tree

Question 2

What is the respiratory zone ?

Answer 2

Bronchi and bronchial tree

Alveoli

Question 3

What is the anatomical dead space ?

How large is it ?

Answer 3

Volume of air located in segments of respiratory tract responsible for conducting air to alveoli and respiratory bronchioles but do not take part in gas exchange itself.
100-150 mL

Question 4

Where does the trachea start and where does it end ?

Answer 4

Starts at C6 and ends at T4/5 at the carina

Question 5

What muscle is present in the trachea? Where is it located ? What is its function ?

Answer 5

Trachealis muscle. Located posteriorly.

Function is to altern tracheal diameter.

Question 6

Where does the incision take place in tracheotomy ? What is the function of tracheotomy ?

Answer 6

Between the 2nd and 3rd ring of cartilage.

Bypassing airway and taking over breathing.

Question 7

Where is the trachea palpable ?

Answer 7

Anteriorly, above the suprasternal notch.

Question 8

How many lobes does each lung have ? How many bronchi ?

Answer 8

R lung has 3 secondary lobar bronchi while L lung has 2 secondary lobar bronchi.
Only 1 bronchus

Question 9

What is the main difference between the R and L bronchus ? Why ?

Answer 9

R bronchus slightly more vertical, wider and shorter so foreign bodies more likely to enter R bronchus.
Because L lung needs to make room for heart and pericardium (in the cardiac notch) so dome of the R lung slightly higher.

Question 10

What are the different blood supplies of the lung ? What is their function ?

Answer 10

Pulmonary artery system,

Bronchial artery system, keeps lung tissue alive (including bronchi)

Question 11

What is the next division following the secondary lobar bronchi ?

Answer 11

Segmental bronchi

Question 12

What is the implication of the pulmonary and bronchial systems joining ?

Answer 12

Most oxygenated blood in the body (just left the lungs) mixes with deoxygenated blood so as leaves the lungs, not as oxygenated as when in the lungs.

Question 13

What are the next divisions following segmental bronchi ?

Answer 13

Conducting bronchioles, then terminal bronchioles, then respiratory bronchioles. Keep decreasing in diameter until alveoli bud from respiratory bronchioles (made up of a duct and a sac)

Question 14

What is the histology of the trachea ?

Answer 14

Pseudo-stratified ciliated columnar epithelium with globlet cells (mucus swept up by cilia so it can be swallowed in oesophagus)

Question 15

What is the histology of the bronchi ?

Answer 15

Similar to trachea BUT height flattened AND cartilage rings replaced by cartilage plates.

Question 16

What is the histology of bronchioles (excluding Term. and Resp. bronchioles) ?

Answer 16

• Epithelium CHANGES from “simple ciliated columnar epithelium to simple ciliated cuboidal epithelium as bronchioles decrease in size”
• Lumen < 1 mm
• Surrounding band of smooth muscle
• Cartilage and glands disappear (bronchioles held open by surrounding lung tissue).

Question 17

What is the histology of Terminal and respiratory bronchioles ?

Answer 17

Epithelium becomes non-ciliated cuboidal and Globet cells disappear

Question 18

What is the histology of alveoli ?

Answer 18

Made of a duct + sac
Separated from each other by SEPTAE (alveolar wall) which is a thin, vulnerable membrane containing capillaries (air/blood barrier for exchange)

Question 19

How are alveoli vascularised ?

Answer 19

Supplied by RBCs in capillaries for gas exchange process

Question 20

What factors contribute to keeping alveoli open ?

Answer 20

• Lung surfactant changes surface tension which enables them to stay open for exchange to happen
• Air P also keeps them open

Question 21

What is the pleura ?

Answer 21

Membranes covering the organs within the cavity and the walls of the cavity

Question 22

What is the pleural cavity ? Why is it important ?

Answer 22

The space between layers of pleura.
Important because contains fluid to lubricate pleural surfaces allowing for smooth gliding movement between parietal and visceral pleura (especially when lungs expand).

Question 23

What is the name of the pleura covering the lungs ?

Answer 23

Visceral/pulmonary pleura

Question 24

What is the name of the pleura covering the cavity walls ?

Answer 24

Parietal pleura (different names for different for specific locations)

Question 25

What side is the trachea slightly deviated towards ? What might further deviation to one side or the other indicate ?

Answer 25

Right.

Problem with a lung or the other.

Question 26

What is strange about visceral/pulmonary pleura and parietal pleura ?

Answer 26

They are actually part of continuous membrane.

Question 27

How come the lungs are partially expanded even without breathing?

Answer 27

Due to the negative Pressure in the membrane.

Question 28

What separates the two lungs ?

Answer 28

Mediastinum

Question 29

How is lung lymph drained ?

Answer 29

Via subpleural plexus and a plexus alongside bronchi

TO HILAR LYMPH NODES (

Question 30

What are the lobes of the L lung called ? What separates these two ?

Answer 30

Superior and Inferior lobes

Oblique fissure

Question 31

What are the lobes of the R lung called ? What separates them ?

Answer 31

Super (horizontal fissure) middle (oblique fissure) inferior lobes

Question 32

What is the surface anatomy of the lungs ?

Answer 32

Superiorly, apex of lungs just above clavicle
Inferiorly, pleura extent down to costal margin but lungs end 2 rib spaces higher (so lungs only 2/3 of lung space)
In breathing, lungs do NOT extent to lower parts of pleural cavity but this allows for deep breathing.

Question 33

What is the hilum of the lungs ?

Answer 33

Root of lungs whereby structure (main bronchus, pulmonary artery and pulmonary veins) pass into and out of the lungs (visible in anterior view of the lungs)

Question 34

How does inspiration occur ?

Answer 34

Negative Pressure created through:
-Diaphragmatic contraction and descent (increased vertical diameter)
-Rib elevation and sternum pushed up and forward thanks to external intercostal muscles (increases anteroposterior and lateral diameters)
Hence air sucked in

Question 35

How does expiration occur ?

Answer 35

Passive process, by muscle relaxation and elastic recoil (aided by internal intercostal muscles)

Question 36

Using the anatomy of the diaphragm, explain how it is contracts in inhalation.

Answer 36

Diaphragm is muscular at its periphery and tendinous centrally.
Diaphragm has R and L domes.
The phrenic nerve stimulates its contraction in which the domes descend, causing negative intra thoracic pressure but raising intra abdominal pressure.

Question 37

What nerves contribute to the phrenic nerve ?

Answer 37

Cervical (C3, C4 and C5) nerves

Question 38

What is a pneumothorax ? How is it fixed ?

Answer 38

When air enters the pleural cavity, resulting in a collapsed lung. Occurs through trauma and some conditions.
Needle inserted just above rib to remove the air to allow lung to expand again. (Must avoid damage to neurovascular bundle running inferior to each rib)

Question 39

What is the appearance of a pneumothorax on a chest radiograph ? Why ?

Answer 39

Increased shadow. Lungs shrink so tissue, blood supply and bronchi give it much lighter shadow.

Question 40

In terms of vascular markings of the lung, what is the difference between the radiograph of a normal lung and that of a pneumothorax.

Answer 40

In the normal lung, lung vascular markings fill the thoracic activity.

In the pneumothorax, lung vascular markings are at the border of the lung.