Basic Anatomy and Histology

Question 1

R v L Lobe

Answer 1

• L lobe = Upper w/ lingula and Lower

- R lobe = Upper, Middle and Lower

Question 2

4 Cell Types in Bronchioles

Answer 2

• Epithelial Cells - range from pseudo columnar to squamous w/ or w/o cilia
• Goblet Cells - interposed b/n epithelial cells but w/o cilia; produce mucus; can see oval cytoplasmic vesicles of mucus inside them
• Basal Cells - layer of progenitors at base of epithelial cells
• Kulchitsky Cells - 1 cell endocrine glands; secretory cells at base of epithelium; have concentrated granules of active peptides that act as paracrine and endocrine factors (ex - serotonin, ADH, calcitonin, somatostatin)

Question 3

Which airway structures have cartilage?

Answer 3

Trachea and bronchi NOT bronchioles

Question 4

Bronchioles v. Terminal Bronchioles v. Resp Bronchioles

Answer 4

• Bronchioles
  
  • Simple columnar
  • Less cilia and goblet cells
  • Full circle of smooth muscle
  • No cartilage
  • Dec submucosal glands
• Terminal Bronchioles
  
  • Simple cuboidal
  • No cilia or goblet cells
  • Inc # clara cells
  • Patches of smooth muscle
  • No cartilage or submucosal glands
• Respiratory Bronchioles
  
  • Low cuboidal
  • Have alveoli outpockets along wall
  • Respiratory gas exchange
  • Clara cells
  • No cilia
  • Patches of smooth muscle

Question 5

What is an acinus?

Answer 5

• unit of 1 bronchiole and all its branches and alveoli

Question 6

Type I v Type II Pneumocytes

Answer 6

• Type I - normal squamous epithelial cells
  
  • Flat
  • Take up 93% of surface but less in #
  • Terminally differentiated
• Type II - granular cells that make surfactant (phos choline)
  
  • Round
  • Take up 7% of surface but more in #
  • Granular cytoplasm
  • Can differentiate into Type I cell in case of lung injury

Question 7

Bronchial Blood Supply

Answer 7

• carries arterial (oxygenated blood) usually from aorta to nourish the bronchi themselves
• This blood then gets returned to L atrium (deoxygenated) so contributes to small amount of normal shunting
• **Transplanted lungs have no bronchial circulation
• High pressure system (v low pressure pulmonary circulation)

Question 8

What 5 layers must oxygen travel thru at alveolar-capillary interface?

Answer 8

• 1- surfactant
• 2- Type 1 pneumocyte
• 3- fused basement membrane
• 4-endothelial cell
• 5-RBC / plasma