lung ventilation

Question 1

What happens in bronchitis

Answer 1

Mucus hyper secretion from goblet cells and reduced cilia so lack of mucus clearing

Question 2

How do bronchus and bronchioles differ

Answer 2

A small bronchus has the presence of small islands of cartilage and glands in the submucosa which bronchioles do not.

Question 3

How is a bronchioles defined

Answer 3

1mm or less in diameter

Question 4

What is emphysema

Answer 4

Abnormal, permanent enlargement of the air space distal to the terminal bronchioles and destruction of alveolar walls and alveolar collapse.

Question 5

what are the causes of emphysema?

Answer 5

Smoking may breakdown elastin or caused by protease mediated destruction of elastin (alpha 1 antitrypsin deficiency) meaning large air spaces.

Question 6

what is asthma?

Answer 6

chronic inflammatory disorder of the airways causing airway narrowing and excess mucous production. airflow is most impeded during expiration. it is reversible.

Question 7

Describe how emphysema leads to its symptoms and what pattern does it show on spirometry?

Answer 7

Loss of elastin means compliance increases but recoil if reduced. Damaged alveoli mean less radial traction so bronchioles collapse and air is trapped in pockets, resulting in a hyper inflated barrel chest. obstructive pattern on spirometry.

Question 8

Symptoms of COPD?

Answer 8

shortness of breath, reduced exercise tolerance, cough

Question 9

How do lung x rays differ in emphysema?

Answer 9

more ribs visible and flattened diaphragm

Question 10

What is the interstitium in the lungs

Answer 10

a microscopic/potential space between alveolar epithelium and capillary endothelium (only becomes apparent in diseased states)

Question 11

what is interstitial lung disease

Answer 11

heterogenous group of disorders characterized by alveolar septal thickening, fibroblast proliferation, collagen deposition and if left unchecked pulmonary fibrosis

Question 12

What is contained within the lung interstitium

Answer 12

Elastin fibres, collagen, fibroblasts, matrix

Question 13

What is idiopathic pulmonary fibrosis and what does it lead to?

Answer 13

Fibrosis of lung interstitium leading to decreased gas exchange (can be end result of interstitial lung disease)

Question 14

What are some causes of interstitial lung disease

Answer 14

Asbestosis, silicosis , pneumoconiosis, radiation, chemo, nitrofurantoin, amiodarone, SLE, sarcoidosis or 20% idiopathic (fibrosis alveolitis), hypersensitivity pneumonitis.

Question 15

What is hypersensitivity pneumonitis?

Answer 15

an immunologically mediated lung disease caused by repetitive inhalation of antigens which leads to interstitial lung disease. mostly caused by birds, or mould on certain crops.

Question 16

What is pneumoconiosis?

Answer 16

interstitial lung disease caused by inhalation of dust such as coal

Question 17

How does lung fibrosis effect lung ventilation and perfusion?

Answer 17

Reduced compliance and increased recoil meaning lung volume is smaller, diffusion distance is greater which effects O2 greater than CO2. Restrictive on spirometry. reduced perfusion- effect of diffusion is greater on O2 as CO2 is more soluble.

Question 18

What are the symptoms of lung fibrosis/ interstitial lung disease

Answer 18

Breathlessness, dry cough, occupation and drug history, reduced exercise tolerance.

Question 19

what are the signs of lung fibrosis/ interstitial lung disease?

Answer 19

reduced chest expansion, tachypnoea, tachycardia, fine crackles.

Question 20

How is the increase in lung volume maximised during forced breathing?

Answer 20

Use of the inspiratory reserve volume IRV

Question 21

how is the decrease in lung volume maximised during forced breathing

Answer 21

Use of the expiratory reserve volume ERV

Question 22

How will emphysema effect functional residual capacity?

Answer 22

Increased

Question 23

How will lung fibrosis effect functional residual capacity

Answer 23

Reduced

Question 24

What is neonatal respiratory distress syndrome NRDS

Answer 24

Preterm babies under 35 weeks don’t produce enough lung surfactant to keep the alveoli open so they collapse and exogenous surfactants must be given

Question 25

How does NRDS effect ventilation

Answer 25

high surface tension means incomplete lung expansion and some alveoli remain collapsed and do not partake in gas exchange. Respiratory difficulty results in impaired ventilation

Question 26

What are the clinical features of NRDS?

Answer 26

grunting, nasal flaring, intercostal and subcostal retractions, tachypnea, cyanosis

Question 27

What’s the treatment for NRDS?

Answer 27

surfactant replaced via an endotracheal tube, oxygen and assisted ventilation

Question 28

What is a pneumothorax?

Answer 28

air in the pleural space due to a breach in the chest wall or lung. Loss of the pleural seal means the lungs elastic recoil isn’t countered, lung compression collapse.

Question 29

What is resorption lung collapse

Answer 29

Collapse due to obstruction of a large airway such as in cancer or mucus plugs

Question 30

What is atelectasis

Answer 30

Alveoli not ventilated and alveolar collapse (lung collapse). A common post operative complication

Where the alveoli aren’t ventilated sp can’t participate in gas exchange -> impaired oxygenation and co2 elimination

collapsed alveoli are more suggestible to lung infection including pneumonia

Question 31

what is compression atelectasis

Answer 31

secondary to increased pressure exerted on the lung causing alveoli to collapse. resulting from pneumothorax or pleural effusion

Question 32

what is resorption atelectasis

Answer 32

complete obstruction of an airway and over time air is resorbed from the alveoli, which collapse. can be caused by bronchial carcinoma.

Question 33

What are some causes of hypoventilation

Answer 33

Guillain-Barré syndrome, trauma, opiates, head injury, myasthenia graves, inherited muscle disease, severe obesity, pneumothorax, large pleural effusions, NRDS, laryngeal oedema, severe acute asthma, late stages of COPD

Question 34

What is a cough

Answer 34

An explosive expiration of air from the lungs which is co-ordinated by the cough centre in the medulla oblongata. It’s initiated by irritation of mechano and or chemo receptors in the respiratory epithelium, this travels through the vagus nerve and impulses come back from the cough centre through the vagus, phrenic and spinal motor never Ss to the diaphragm, abdominal wall and muscles

Question 35

What are the steps involved in a normal cough

Answer 35

Vocal cords abduct, deep inspiration, glottis closed by vocal cord adduction, strong contraction of the expiratory muscles which builds intrapulmonary pressure, sudden opening of the glottis causes an explosive discharge of air.