Respiratory System

Question 1

What are the two membrane types present in the respiratory system?

Answer 1

Mucous membranes - line the conducting portion of the respiratory tract (contain goblet cells)

Serous membranes - line the pleural sacs which envelope the lungs - 2 layers with lubricating fluid fluid between them

Question 2

What is caused by the pleural cavity filling with air?

Answer 2

Pneumothorax

Question 3

What is caused by the pleural cavity filling with blood?

Answer 3

Haemothorax

Question 4

What is caused by the pleural cavity filling with pus?

Answer 4

Empyema

Question 5

What is caused by the pleural cavity filling with watery transudate?

Answer 5

Pleural effusion

Question 6

How can fluid be drained from the pleural cavity?

Answer 6

Inserting a wide- bone needle through the 7th intercostal space posteriorly under ultrasound guidance

Question 7

What is the order of the respiratory tract?

Answer 7

Nasal cavity
Nasopharynx
Oropharynx
Larynx
Trachea
Bronchi (primary and secondary)
Bronchioles
Terminal bronchioles
Respiratory bronchioles 
Alveolar ducts
Alveoli

Question 8

What is the conducting portion of the respiratory tract?

Answer 8

Nasal cavity to terminal bronchioles

Question 9

What is the respiratory portion of the respiratory tract?

Answer 9

Respiratory bronchioles to alveoli

Question 10

What portion of the respiratory tract is extra pulmonary?

Answer 10

Nasal cavity to primary bronchioles

Question 11

What part of the respiratory tract is intrapulmonary?

Answer 11

Secondary bronchi to alveoli

Question 12

What epithelium is the respiratory tract lined with?

Answer 12

Nasal cavity to secondary bronchi = pseudostratisfied epithelium (cilia and goblet cells)

Bronchioles to terminal bronchioles = simple columnar epithelium (cilia and Clara cells, no goblet cells)

Respiratory bronchioles to alveolar ducts = simple cuboidal epithelium (Clara cells and scattered cilia)

Alveoli - simple squamous epithelium

Question 13

What are the olfactory regions of the nasal cavity?

Answer 13

Particularly thick pseudostratisfied epithelium without goblet cells. Cilia are non motile (increaseue surface area). Contains olfactory cells (containing bipolar neutrons) in which cilia respond to odours. Lamina propria and submucosa blend - contain serous glands to flush odourants from epithelial surface and olfactory nerves.

Question 14

What are the non-olfactory regions of the nasal cavity?

Answer 14

Pseudostratisfied ciliates epithelium containing mucus glands and venous sinuses in the lamina propria. Venous plexusesswell every 20-30 mins alternating airflow from side to side to prevent over drying. Arterial blood flow warms inspired air

Question 15

How many vocal cords make up the larynx?

Answer 15

2 “fake” vocal cords and 2 true vocal cords split by a ventricle.

Question 16

What is each vocal cord lined with?

Answer 16

Stratified squamous epithelium and contain a vocal ligament (large bundle of elastic fibres) and a vocalis muscle (bundle of skeletal muscle)

Question 17

What are the function(s) of the vocal chords?

Answer 17

Resonances of voice

Stop foreign objects reaching the lungs - close to build up pressure when coughing is required

Question 18

What is the structure of the trachea?

Answer 18

Lined by pseudostratisfied ciliates epithelium and thick basement membrane
Submucosa - contains seromucous glands
C shaped hyaline cartilage ring (partly ossified to bone during aging)

Question 19

What are contained in the secretions from the epithelium and submucosal glands of the trachea/bronchi?

Answer 19

Mucins, water, serum proteins, lysozyme, antiproteases, lymphocytes, immunoglobulins (especially IgA)

Question 20

What happens to goblet cells in COPD?

Answer 20

Goblet cell hyperplasia - smaller proportion of ciliates cells and hypertrophy of submucous glands. So fewer cilia and less nucleus.

Question 21

What’s the difference is histology between primary and secondary/tertiary bronchi?

Answer 21

Similar histology
Except secondary and tertiary bronchi have cartilage arranged as irregular crescent shaped islands instead of rings.
Smaller diameter

Question 22

What artery carries blood to alveoli and which vein back?

Answer 22

Pulmonary artery carried deoxygenated blood down bronchioles (alongside bronchial artery) to alveoli.
The blood carried through capillary plexus.
Then oxygenated blood carried back to the heart via pulmonary vein

Question 23

What are the features of bronchioles?

Answer 23

No cartilage or glands
1mm or less in diameter
Surrounded by alveoli (keep lumen open)
Surrounded by smooth muscle

Question 24

What is the significance of no cartilage in bronchioles?

Answer 24

It allows the air passages to construct and almost close sigh smooth muscle contraction.
(This bronchoconstriction becomes excessive in asthma - cause difficultly expiring (as the bronchial walls no longer held open by surrounding alveoli)

Question 25

What are Clara cells?

Answer 25

Interspersed between cuboidal cells in small bronchioles. They secret a surfactant lipoprotein that prevents the walls sticking together during expiration. Also secrete abundant Clara cell protein (CC16)

Question 26

Low CC16 in bronchoalveolar lovage fluid means what?

Answer 26

Lung damages - CC16 is a measurable marker

Question 27

A high CC16 in serum means what?

Answer 27

Leakage a cross the air - blood barrier a measurable marker in serum

Question 28

What are the features of alveoli?

Answer 28

Alveolar walls have abundant capillaries Supported by a basket work of elastic and reticular fibres Have a covering composed of type 1 pneumocytes and a scattering of type 2 pneumocytes

Question 29

What are type 1 pneumocytes?

Answer 29

Squamous cells. Cover ~90% of surface area and permit gases exchange with capillaries (across blood-air barrier)

Question 30

What are type 2 pneumocytes?

Answer 30

Cuboidal cells. Cover ~10% of surface area and contain lamellar bodies (secretory organelles) secrete surfactant (similar to Clara cells)

Question 31

What are the two main causes of emphysema?

Answer 31

Cigarette smoking | Alpha-1-antitrypsin deficiency

Question 32

What is emphysema?

Answer 32

Destruction of alveolar walls and permanent enlargement of air spaces (as alveoli normally hold bronchioles open during expiration, when damaged bronchioles collapse - difficult for lung to empty, air trapped in alveoli)

Question 33

What is a hallmark sign of emphysema?

Answer 33

Pursed lip breathing

Question 34

What is pneumonia?

Answer 34

Inflammation of the lung caused by bacteria - lung consolidates as alveoli fill with inflammatory cells

Question 35

What bacteria commonly cause pneumonia?

Answer 35

Streptococcus pneumoniae H. Influenzae S. Aureus m

Question 36

What is surface tension?

Answer 36

Liquid has a tendency to resist rupture when placed under stress due to water molecules at surface forming strong hydrogen bonds with their neighbours

Question 37

What is the function of the lubricating fluid between the pleural membranes?

Answer 37

Reduces friction, allowing pleura to slide easily during breathing . Fluid provides surface tension to prevent the lung recoiling and collapsing.

Question 38

What is Boyles law?

Answer 38

When the volume of a container increases, pressure decreases. I.e. Diaphragm down (contracted), increased thoracic cavity volume, decreased pressure - so air moves from an area of high pressure (from atmosphere into lungs)

Question 39

What is an open pneumothorax?

Answer 39

Opening in the chest wall (with/without lung puncture), allows atmospheric air to enter pleural space

Question 40

What are the potential causes of an open pneumothorax?

Answer 40

``` Penetrating trauma (stab wound, gunshot) Surgery ```

Question 41

What is a closed pneumothorax?

Answer 41

Chest wall in tact, rupture of lung and visceral pleura (or airway) allows air into pleural space

Question 42

what is the role of surfactant in inspiration?

Answer 42

When alveoli expand, surfactant molecules move apart, increased surface tension.

Question 43

What is the role of surfactant in expiration?

Answer 43

Ehh lungs shorten, surfactant molecules move together and become more concentrated, reduced surface tension (without surfactant alveoli can't inflate)