Lung Microanatomy/Lung Histology

Question 1

Main conducting airways and lung lobes

Answer 1

• larynx ==> trachea ==> L and R primary bronchi ==> secondary/lobar bronchi ==> lobes of lung ==> bronchioles ==> terminal bronchioles ==> respiratory bronchioles
• R lobes: upper right, middle right, and lower right
• L lobes: upper left, lower left

Question 2

Containment structure surrounding lungs

Answer 2

• pleural layers ==> pleural cavity that holds lungs
• lung covered by visceral pleura (mesothelium + etc.)
• parietal pleura lies against connective tissue of ribs

Question 3

Histologic composition of trachea

Answer 3

• “c-shaped” cartilagenous rings
• rings connected posteriorly by trachealis muscle
• inner pseudostratified epithelia layer
• submucosa of connective tissue
• lamina propria = mucosa
• epithelium = ciliated epithelial, goblet cells, basal cells, neuroendocrine cells

Question 4

Histologic composition of large bronchi

Answer 4

• “c-shaped” cartilagenous rings

r extending around entire diameter

• inner pseudostratified epithelia layer
• muscularis smooth muscle between epithelial layer and submucosa
• submucosa of connective tissue
• lamina propria = mucosa
• epithelium = ciliated epithelial, goblet cells, basal cells, neuroendocrine cells

Question 5

Fxn of various epethial/submucosa cells

Answer 5

• cila ==> helps push out pollutants
• goblet cells ==> secret mucins and other proteins
• submucosa glands ==> mucus + secretions to mucosal surface

Question 6

Histology of bronchioles

Answer 6

• smaller airways
• no cartilage
• smooth muscle
• epithelium w/cilia and goblet cells
• ==> terminal bronchioles = increasing numbers of Clara cells ==> secret surface-active substances

Question 7

Begining of gaseos exchange system composition

Answer 7

• terminal bronchioles ==> respiratory bronchioles ==> alveoli
• respiratory bronchioles = epithelium w/Clara cells + smooth muscle layer
• alveolar ducts ~ alveolar-bound channels
• gas exchange @ alveolar saccules

Question 8

Alveoli structure

Answer 8

• chambers separated by interalveolar septa
• Type I & Type II pneymocytes = cells on alveolar septa facing air supplu
  
  • Type I = thin, flat cover most of surface facing air supply
  • Type II = rounded, progenitors of type I cells, ganules w/surfactant ==> lowers surface tension in alveoli and prevents lung collapse and excessive drying

Question 9

Air-blood barrier =

Answer 9

• the surfactant layer==>
• the plasma membranes and cytoplasm of thin type I cell ==>
• common basal lamina between the type I cell and the capillary epithelium ==>
• plasma membranes and cytoplasm of the endothelial cell

Question 10

Components of alveor defense

Answer 10

• loose connective tissue @ alveolar septa contains monocytes, neutrophils, and fibroblasts
• monocytes ==> alveolar macrophages ==> can enter alveolar space

Question 11

Lung vasculature components

Answer 11

• systemic arteries (bronchial arteries from aorta) ==> supply O₂ to conduction system
• pulmonary arteries from RV ==> alveoli ==> pulmonary veins ==> LA