1.4 and 1.8 Anatomy and Development

Question 1

What are the 2 pleural layers of the lung and what are their innervations?

Answer 1

Visceral pleura (inner layer)-autonomic nn., 
Parietal pleura (outer layer)-phrenic and intercostal n.

Question 2

How many lobes and functional units are in the right lung vs the left?

Answer 2

Right lung-3lobes/10 functional units; Left lung- 2 lobes 10 functional units

Question 3

In terms of broncho-/vaso- mechanics, what would a sympathetic response elicit vs a parasympathetic responses?

Answer 3

Sympathetic- broncho-/vaso- dilation; Parasympathetic- broncho-/vaso- constriction

Question 4

What is the surgical term for the removal of a segment?; removal of a lobe?

Answer 4

Segment- segmentectomy; Lobe-lobectomy

Question 5

What are the primary muscles of respiration?

Answer 5

diaphragm, costals (external, internal, subcostal, transversus thoracis)

Question 6

What are the secondary muscles of respiration?

Answer 6

Abdominal muscles, anything that can stabilze or constrict thorax (musc of upper limbs)

Question 7

Generally, L lymphatics drain into the L subclavian and R lymphatics drain into the R subclavian, what is the exception?

Answer 7

L lymphatics can cross to the R. Problematic when trying to identify original location of cancerous cells.

Question 8

When a child aspirates due to a swallowed object entering the lung, where is the object most likely to be found and why?

Answer 8

Most likely on the R ride because it is larger and more vertical. The left is tilted up and slightly smaller because of the constraints of the heart on the L side

Question 9

What embryological structure do the pulmonary buds grow out through?

Answer 9

The laryngotracheal groove. Grows caudally and develops into brachio-pulmonary tree

Question 10

What is the embryological origin of the visceral and parietal pleura?

Answer 10

Visceral-Splanchnic mesoderm; Parietal-Somatic mesoderm

Question 11

What significant lung-related events occur during birth?

Answer 11

1. Fluid squeezed out of the lung.
2. This expands the lung and decreases the resistance to the pulm circulation. R heart is able to pump to lungs.
3. Foramen ovale closes because increased input in L heart.
4. Ductus arteriorsus closes because of increased O2

Question 12

What are the fissure(s) of the L lung?

Answer 12

Oblique fissure

Question 13

How long does it take for the lung to fully develop?

Answer 13

It takes up to 8 years after birth to fully develop

Question 14

How much of an impact does the contraction of the diaphragm and moving of the rib wall have on the volume of inhalation?

Answer 14

3L added by a contracting diaphragm, 3L by rib wall movement

Question 15

What’s Stage 1 of lung development called and what is it characterized by?

Answer 15

Stage 1- Pseudoglandular 6-16 weeks- terminal bronchiole branches present but no alveoli, thus no gas excahnge.

Question 16

What’s Stage 2 of lung development called and what is it characterized by?

Answer 16

Stage 2- Canalicular- 16-26 weeks- more vasculature and alveoli development started; alveoli still non-functional

Question 17

What’s Stage 3 of lung development called and what is it characterized by?

Answer 17

Stage 3- Terminal Sac- 26 weeks to birth; Alveoli developed but non-functional until birth due to high resistance

Question 18

What’s Stage 4 of lung development?

Answer 18

Stage 4 - Alveolar- birth to 8 years