Lecture 4 - Anatomy of the Respiratory System (Part 2)

Question 1

What supplies and drains blood to and from the intercostal space/muscles?

Answer 1

• The intercostal space receives and drains blood from via the anterior and posterior intercostal arteries and veins. And, receive innervation from the intercostal nerve.
• These 3 run between the internal and innermost intercostal muscles.

Question 2

What system is responsible for drainage of the intercostal spaces?

Answer 2

The azygos system, which receives intercostal veins at all of the different levels.

Question 3

Explain how the lung is split into lobes

Answer 3

• Right lung has 3 lobes (superior, middle & inferior)
• Left lung has 2 lobes (superior & inferior) - absence of middle lobe due to presence of heart
• Separated by fissures (horizontal & oblique), because inferior fissure is oblique, posterior lobe makes up large proportion of inferior aspect of lungs

Question 4

Why do aspirated objects typically lodge on the right side of the chest rather than the site?

Answer 4

• Right main bronchus follows a straighter/steeper path than left main bronchus, making this the most probable route after bifurcation of the trachea.

Question 5

What is the mediastinum & how is it split up?

What major structures are within the mediastinum?

Answer 5

• Mediastinum is space between lungs, split into the superior and inferior mediastinum at the T4/T4 plane
• Heart in the middle component, anterior compartment contains thymus gland, posterior contains thoracic aorta, rest of oesophagus and thoracic duct.

Question 6

What are the 3 major components of the chest cavity pleura?

What is the nerve supply to these areas components and what does this mean for pain in this area?

Answer 6

Visceral pleura = in contact with lung
Parietal pleura = in contact with chest wall cavity
Intrapleural space = containing a small amount of fluid for lubrication

Nerve supply to visceral is autonomic, pain poorly localised.

Nerve supply to parietal is somatic, irritation is well localised

Question 7

What is the costodiaphragmatic recess and its role?

Answer 7

A space within the pleural cavity that enables the lungs to expand into it during inspiration to fill up its full volume

Question 8

What provides and drains blood to and from the lungs?

Answer 8

• Deoxygenated blood delivered by a pair of pulmonary arteries
• Deoxygenated blood leaves via 4 pulmonary veins
• Bronchi, lung roots, visceral pleura and supporting lung tissue require extra supply from bronchial arteries which arise from descending aorta

Question 9

Which side does the diaphragm sit higher on and why?

Answer 9

Right side sits higher than the left due to presence of the right lobe of the liver

Question 10

What are the structures that may be damaged by a neck stab wound?

Answer 10

If blade has been pushed inferiorly, it may have entered thorax, risk of pneumothorax as pleura at the apex of the lungs extends into the neck