INCORRECT EXAMPREP Q'S - RESPIRATORY

Question 1

What do the walls of the trachea, bronchi and bronchioles consist of?

Answer 1

An outer fibrous layer with supporting pieces of cartilage & bronchial smooth muscle

Question 2

How is bronchial smooth muscle arranged?

Answer 2

In clockwise and anticlockwise helical bands

- there is a matrix of elastic tissue supporting the muscles

Question 3

What is surfactant secreted by? What is it made up of? What is its action on the body?

Answer 3

From type II pneumocytes in alveoli, essentially a mix of lipids and proteins, the major component being dipalmitoylphosphatidylcholine
Main action is to lower alveolar surface tension which increases compliance of the lung (stiff lungs have low compliance)

Question 4

Define compliance.

Answer 4

The change in lung volume per unit change in airway pressure

Question 5

To which structure do the hilar lymph nodes drain?

Answer 5

Bronchopulmonary nodes

Question 6

How many lobar bronchi are present within the left lung?

Answer 6

2

Question 7

How long does equilibration of pO2 take to achieve in the pulmonary capillaries?

Answer 7

0.25 seconds (approx)

Question 8

Transpulmonary pressure is the difference between the alveolar and intrapleural pressure. At what stage of pulmonary ventilation is this pressure greatest?

Answer 8

End of respiration

Question 9

At the start of normal respiration, what is the difference (in mmHg) between intrapulmonary pressure and atmospheric pressure?

Answer 9

-3 mmHg

Question 10

The gap between the alveolar space and the pulmonary circulation is known as the gas-blood barrier. What type of cells does this barrier consist of?

Answer 10

Type I and Type II alveolar cells

Question 11

How many times does the respiratory tree branch from trachea to the alveoli?

Answer 11

23 branches

- giving rise to around half of the 250-300 million alveoli

Question 12

What intermediate extrinsic muscle of the back act on the ribs to assist respiratory movement?

Answer 12

Levator costarum

Question 13

Where are the respiratory changes associated with coughing and sneezing produced?

Answer 13

Hypothalamus

Question 14

Say whether the following are obstructive or restrictive lung diseases; (i) ARDS (ii) chronic bronchitis (iii) pneumothorax (iv) pulmonary embolism (v) pulmonary fibrosis?

Answer 14

(i) restrictive
(ii) obstructive
(iii) restrictive
(iv) restrictive
(v) restrictive

Question 15

1. What are the general causes of pulmonary oedema? 2. What is the commonest cause? 3. What are other causes of increased venous hydrostatic pressure?

Answer 15

1. Increased pulmonary venous hydrostatic pressure, reduced plasma oncotic pressure, increased permeability of the alveolar capillary wall and blockage of lymphatic drainage
2. increased pulmonary venous hydrostatic pressure due to LVF
3. mitral stenosis and severe aortic stenosis

Question 16

1. What is primary tuberculosis best described as? 2. What is the immune reaction mediated by?

Answer 16

1. Granulomatous lesions with central caseation, surrounded by epitheloid and Langerhans giant cells
   - the initial focus of infection is a small subpleural granuloma accompanied by granulomatous hilar lymph node infection. These make up the Gohn complex
2. Type IV hypersensitivity where killing is mediated by T lymphocyte recruitment and actiavtion of macrphages by cytokines - this inflammatory reaction causes necrosis

Question 17

Define (i) Type 1 respiratory failure (ii) Type 2 respiratory failure.

Answer 17

(i) low oxygen and normal carbon dioxide (or decreased)
- typically caused by V/Q mismatch, high altitude, hypoventilation, shunt
(ii) low oxygen and increased CO2
- COPD, asthma, Guillain-Baree syndrome, extreme obesity

Question 18

Why is recovery from a major operation a significant risk factor for pulmonary embolism? What are 3 other risk factors?

Answer 18

Pulmonary emboli tend to originate from thrombi in legs which are initiated by valves causing turbulent blood flow. The flow of blood in legs depends on calf muscle contraction so immobilation is a major risk factor. During an op BP may fall and stasis in leg veins may occur.
Malignancy - as may increase blood viscocity
Contraceptive pills
Pregnancy

Question 19

What type of lung tumour metastasises very early, is made up of blue cells and may secrete hormones e.g. ADH?

Answer 19

Small cell carcinoma

Question 20

1. When does respiratory failure occur? 2. What can it be caused by?

Answer 20

1. When hypoxia and CO2 retention occur due to ineffective gas exchange
2. Ventilation defects, perfusion defects, or defects of gas exchange

Question 21

What are causes of (i) ventilation defects (ii) V/Q mismatch (iii) Defects of gas exchange?

Answer 21

(i) mechanical factors (obesity, severe abnormal curvature of spine)
Muscle weakness (muscular dystrophy, paraplegic poliomyelitis)
loss of lung volume (collapse of lung lobe)
(ii) multiple pulmonary emboli
(iii) pulmonary fibrosis or emphysema

Question 22

What are the main afferent inputs of the cough reflex?

Answer 22

Stimuli to the trachea or larynx

Question 23

What is sarcoidosis?

Answer 23

A multisystem disorder that often mainly affects mediastinal lymoh nodes and lungs; pt may be asymptomatic or have non-specific tiredness and cough. Presence in the lung of discrete non-caseating granulomas

Question 24

What do pulmonary emboli do to the (i) anatomical (ii) physiological dead space?

Answer 24

(i) Nothing

(ii) significantly increased

Question 25

What would cause the oxygen-haemoglobin dissociation curve to be shifted to the left? Explain why.

Answer 25

Decreased 2,3 DPG in red cells

DPG is found in erythrocytes and is reduced in non-exercising muscles i.e. when there is reduced glycolysis