The Respiratory System

Question 1

What is the serous membrane that lines the lungs called?

Answer 1

The pleural sacs

Question 2

What is the space inbetween the 2 serous membranes surrounding the lungs?

Answer 2

The pleural cavity

Question 3

Where do intercostal vessels and nerves run along rib? What part of the rib is this aspect found?

Answer 3

The run along the costal groove - this is located on the inferior aspect of the rib

Question 4

What nerves supply the diaphragm?

Answer 4

The left and right phrenic nerves

Question 5

What are the terms used to describe air, blood, or pus filling the pleural cavity?

Answer 5

Air - pneumothorax
Blood - heamothorax
Pus - empyema

Question 6

What is a pancoast tumor?

Answer 6

A pancoast tumor is a tumor or the pulmonary apex

Question 7

What nerve may be blocked by a pancoast tumor and cause atrophy of muscles in the arm?

Answer 7

The brachial plexus

Question 8

Where does the conducting portion of the respiratory system end?

Answer 8

At the terminal bronchioles

Question 9

Where does the intrapulmonary portion of the respiratory system begin?

Answer 9

The secondary bronchi

Question 10

List the structures of the respiratory airway, starting with the nasal cavity and finishing with the alveoli.

Answer 10

Nasal cavity - Pharynx - Larynx - Trachea - Primary bronchi - Secondary bronchi - Bronchioles - Terminal bronchioles - Respiratory bronchioles - Alveolar ducts - Alveoli

Question 11

What’s to only part on the conducting portion of the respiratory airway that doesn’t contain goblet cells?

Answer 11

The terminal bronchioles

Question 12

What disorder can a pancoast tumor at the apex of the lungs give rise to? What is this disorder characterised by?

Answer 12

A pancoast tumor can impinge on nerves of the sympathetic trunk, leading to Horner’s Syndrome, which is characterised by:

• miosis - a constricted pupil
• ptosis - a weak, droopy upper eyelid
• anhidrosis - localised decreased sweating

Question 13

How may cancer of the lung result in a hoarse voice?

Answer 13

Impingement of the left recurrent laryngeal nerve

Question 14

How many lobes does each lung have?

Answer 14

The right lung has 3 lobes

The left lung has 2 lobes

Question 15

What is the first structure classified as part of the respiratory portion of the lung?

Answer 15

The respiratory bronchioles

Question 16

Which bronchus (left/right) is more likely to be blocked? Why?

Answer 16

The right bronchus, as this bronchus is more vertical

Question 17

What type of cartilage surrounds the trachea? Does this completely circumnavigate the tracheal lumen?

Answer 17

Hyaline cartilage - no, as its posterior wall is backed by the oesophagus

Question 18

How does COPD affect the trachea?

Answer 18

There is goblet cell hyperplasia, a reduction in the number of cilia, and hypertrophy of the submucosal glands - overall more mucus, and left cilia to shift it and its contents

Question 19

Describe the variation in epithelium across the respiratory system.

Answer 19

• initially, there is pseudostratified epithelium spanning from the nasal cavity to the larger bronchioles
• the terminal bronchioles consist of simple columnar epithelia
• the respiratory bronchioles consist of simple cuboidal epithelia
• the alveoli consist of simple squamous epithelia, to reduce distance for gaseous exchange

Question 20

Why type of epithelium would you find at the ventricular folds of the larynx? What epithelium would you find at a vocal chord? What does a vocal,chord consist of?

Answer 20

You would find pseudostratified epithelia at the ventricular folds of the larynx - you would,find simple squamous epithelia at a vocal chord, which consists of a vocal ligament and a vocalis muscle

Question 21

Describe the layers of the trachea.

Answer 21

Mucous membrane, followed by a submucosa consisting of pseudostratified epithelium - a layer of hyaline cartilage followed by the adventitia

Question 22

Do pulmonary arteries carry oxygenated or deoxygenated blood?

Answer 22

Deoxygenated blood

Question 23

Do bronchioles contain glands?

Answer 23

No - these are last seen in bronchi

Question 24

Do bronchioles contain cartilage? How may this be problematic?

Answer 24

No - this absence of cartilage can be problematic as it allows the airways to fully close (bronchoconstriction) - in asthma this is an issue as it means expiration is more difficult than inspiration

Question 25

What is an alveolar sac?

Answer 25

An air space onto which several alveoli open

Question 26

What type of fibres support alveoli?

Answer 26

Elastin and reticular fibres

Question 27

Where do alveoli first start appearing in the respiratory system?

Answer 27

The terminal bronchioles

Question 28

How is the respiratory tract affected in cystic fibrosis?

Answer 28

A lack of the CFTR in the apical membrane of the airways means that Cl- ion transport across the epithelium if compromised - in turn water cannot move across the epithelium, so the mucosal layer is extremely viscous - the mucus is harder to move, and a serious pulmonary infection is more likely to occur

Question 29

What replaces goblet cells as bronchioles get smaller?

Answer 29

Clara cells

Question 30

What other cell-type is abundant at the alveolar surface?

Answer 30

Macrophages (to phagocytose harmful particles)

Question 31

What are type I alveolar cells? What proportion of the alveoli do these cells cover?

Answer 31

Simple squamous cells which aid rapid diffusion of gaseous exchange - they cover 90% of the alveoli

Question 32

What is the function of a Clara cell?

Answer 32

Secretes surfactant lipoprotein, which prevents the bronchiole walls sticking together during expiration

Question 33

What are type II alveolar cells? What proportion of the alveoli do these cover?

Answer 33

Cuboidal cells which produce surfactant, which decreases friction - these cells cover 10% of the alveoli

Question 34

What Clara cell product can be used as a measure? What can this measure?

Answer 34

Clara cell protein (CC16) - levels of this can be used to measure:

• bronchoalveolar lavage fluid (if lowered then there is lung damage)
• if raised in the serum there is leakage across the air-blood barrier

Question 35

Describe briefly the pathogensis of pneumonia.

Answer 35

Pneumonia is an inflammation of the lungs resulting form bacterial infection - the walls of the lung become consolidated as the alveoli fill with inflammatory cells

Question 36

Describe briefly the pathogenesis of emphysema.

Answer 36

In emphysema there is widespread destruction of the alveolar walls and as a result permanent enlargement of the air spaces - alveolar walls normally hold bronchioles open - when these are damaged bronchioles collapse, making it difficult for the lungs to empty - air becomes trapped inside the alveoli

Question 37

What is a hallmark symptom of emphysema?

Answer 37

Pursed-lip breathing

Question 38

What is the pleural cavity normally filled with? What is its function?

Answer 38

Pleural fluid - this reduces surface tension (to prevent the lung recoiling and collapsing) and reduces friction (allowing the pleura to slide easily during breathing)

Question 39

What is Boyle’s Law?

Answer 39

When the volume of a container increases, the pressure decreases
When the volume of a container decreases, the pressure increases

Question 40

What is the normal pleural fluid quantity per lung?

Answer 40

Approx 25ml per lung (50ml per person)

Question 41

How does Boyle’s Law relate to the diaphragm?

Answer 41

When the diaphragm contracts it moves down, increasing the space within the lungs and decreasing the pressure, allowing air to rush in
When the diaphragm relaxes it pushes upwards, decreasing the space within the lungs and increasing the pressure, forcing air out of the lungs

Question 42

What are the intrapleural pressures during inspiration and exhalation?

Answer 42

During exhalation the intrapleural pressure is -8cmH20

During inspiration the intrapleural pressure is -4cmH20

Question 43

What is the mechanism affecting the lung in a pneumothorax?

Answer 43

If air enters the pleural space the -4cmHO gradient that keeps the lungs against the chest wall disappears, causing the lung to collapse

Question 44

Is the visceral pleura the inner or outer membrane of the pleura?

Answer 44

The visceral membrane is the inner membrane of the pleura - the parietal membrane is the outer membrane