SM 151a - Lung Anatomy and Histology

Question 1

What cells reduce surface tension in bronchioles?

Answer 1

Club cells

Question 2

What is an acinus?

Answer 2

The portion of the lung supplied by a terminal bronchiole

Question 3

When does lung epithelium begin to differentiate from simple cuboidal epithelium?

Answer 3

During the pseudoglandular period (6-16 weeks)

Question 4

The costodiaphragmatic recess extends ____ ribs below the lung margins to rib ____ posteriorly and rib ____ anteriorly

Answer 4

The costodiaphragmatic recess extends 2** ribs below the lung margins to rib **12** posteriorly and rib **10 anteriorly

Question 5

Which structure leaves the impression indicated by arrow #3?

Answer 5

Esophagus

(This is the right lung)

Question 6

What is the highest intercostal space a needle could be inserted laterally into the thorax and miss the lung tissue?

Answer 6

8th

Question 7

What kind of epithelium is found in the bronchi?

Answer 7

Pseudostratified columnar epithelium

Question 8

What kind of epithelium is found in the trachea?

Answer 8

Pseudostratified columnar epithelium

Question 9

Where is the most proximal part of the airway in which gas exchange can occur?

Answer 9

Respiratory bronchioles

Question 10

When is the pseudoglandular period of embryonic lung development?

What is occurring?

Answer 10

6-16 weeks

• Airway resembles an exocrine gland
• Branching to terminal bronchiles
• Epithelium begins to differentiate
• Blood vessels elaborate

Question 11

When in embryonic development does the laryngeotracheal diverticulum (lung bud) appear?

Answer 11

4-5 weeks

Question 12

When is the alveolar stage of lung development?

What is occurring?

Answer 12

32 weeks - 8 years

• Alveoli and acni continue to develop
• More generations of airway branching continue
  
  • Only 1/2 of adult alveoli are present at birth

Question 13

Each tertiary bronchi supplies a ______________.

Answer 13

Each tertiary bronchi supplies a bronchopulmonary segment.

Question 14

During the embryonic period, what kind of epithelium is present in the lung bud?

Answer 14

Undifferentiated simple cuboidal

Question 15

When is the sacular (terminal sac) stage of embryonic lung development?

What is occuring?

Answer 15

26 weeks - birth

Alveolar epithelium differentiates into type I and type II pneumocytes

Type II pneumocytes begin to produce surfactant

Question 16

When is the canalicular stage of embryonic lung development?

What is signfiicant about the end of this stage?

Answer 16

16-26 weeks

At 26 weeks, breathing is structurally possible (capillaries are close to the lumen, epithelium at alveoli is very thin), but the lungs do not yet produce surfactant (usually 28 weeks)

Question 17

Which structure leaves the impression indicated by arrow #12?

Answer 17

Aorta

(This is the left lung)

Question 18

What kind of epithelium is found in the bronchioles?

Answer 18

There is a transition in epithelium from proximal to distal bronchioles

• In the large bronchioles
  
  • Ciliated, pseudostratified columnar epithelium with goblet cells
• In the terminal bronchioles
  
  • Simple cuboidal epithelium with club cells
  • No goblet cells, few ciliated cells

Question 19

The lungs extend inferiorly to rib ____ posteriorly and rib _____ anteriorly

Answer 19

The lungs extend inferiorly to rib 10** posteriorly and rib **8 anteriorly