Respiratory Histology

Question 1

Larynx cartilage

Answer 1

Wall is reinforced by hyaline cartilage and smaller elastic cartilages

Question 2

True vocal cords tissue

Answer 2

Nonkeratinized stratified squamous epithelium

Question 3

Respiratory epithelium

Answer 3

Pseudostratified ciliated columnar epithelium
Contains ciliated cells and goblet cells
Basal cells

Question 4

Tracheal layers

Answer 4

Mucosa- respiratory epithelium w/elastic, fiber rich lamina propria
Submucosa- denser CT than lamina propria
Cartilaginous layer- hyaline cartilage
Adventitia- trachealis muscle, CT that binds trachea to adjacent structure

Question 5

Bronchiole histology

Answer 5

Large bronchi: simple ciliated columnar epithelia
Small: simple cuboidal
Few goblet cells, club cells
Increased elastic fibers
No cartilage plates

Question 6

Club cells

Answer 6

Non ciliated, dome shaped cells
Secrete lipoprotein that prevents luminal adhesion w/airway collapse during expiration
Detoxification of inhaled materials
Secrete antimicrobial products
Previously known as clara cells

Question 7

Respiratory bronchioles

Answer 7

First part of respiratory portion
Simple cuboidal epithelium w/club cells
Smooth muscle, elastic fibers

Question 8

Alveolar ducts

Answer 8

End in alveolar sacs

Alveolar sacs are 2+ clusters of alveoli

Question 9

Alveolar rings

Answer 9

Aggregates of smooth muscle, collagen and elastic fibers that form rings around alveolar ducts
Simple squamous epithelium

Question 10

Alveoli

Answer 10

Blind-ended sacs that are lined with type I and II pneumocytes
Simple squamous epi with supporting tissue/blood vessels
Alveolar pore- small openings that permit air movement b/w alveoli

Question 11

Type I pneumocytes

Answer 11

Flat
Line almost entire alveolar surface
Create surface for gas exchange, closely associated w/ capillaries

Question 12

Type II pneumocytes

Answer 12

Cuboidal/rounded
Secrete surfactant via exocytosis
Precursor for type I and II

Question 13

Lungs are lined by

Answer 13

Serous membrane, the parietal and visceral pleurae
Parietal lines internal cavity wall
Visceral lines the organ (lungs)
Separated by pleural cavity, contain serous fluid
Covered in a flattened mesothelium
Underlying fibrous tissues of collagen and elastin fibers

Question 14

Blood-air barrier

Answer 14

Air in the alveoli and blood in the capillary are separated by 3 components:
2-3 highly attenuated, thin cells lining aveolus (type II pneumocytes)
Fused basal laminae of those cells and the endothelial cells of capillaries
Capillary endothelial cells

Question 15

Asthma

Answer 15

Sudden constriction of smooth muscle in the bronchioles- bronchiole spasm
Infiltration of bronchiolar wall by eosinophils, lymphocytes and mast cells
Thick bronchiolar epi w/increased goblet cells, thick basement membrane and hyperplastic smooth muscle cells

Question 16

Asthma symptoms

Answer 16

Dyspnea, wheezing, productive cough

Question 17

Emphysema

Answer 17

Permanent enlargement of air spaces distal to terminal bronchiole
-chronic obstruction of airflow due to narrowing of bronchioles
-accompanied by destruction of alveolar walls
Significant loss of gas exchange
Causes: smoking cigarettes, chronic inhalation of particulate material, genetic predisposition

Question 18

Pneumonia

Answer 18

Inflammation of lung tissue
Air spaces are filled with exudate containing WBCs (mainly neutrophils), RBCs and fibrin - red hepatization stage (looks like liver)
Enlarged capillaries, congested with RBCs
On gross exam lung appears red, firm and heavy
-Fever, chills, productive cough, decreased breath sounds, crackles in lungs

Question 19

Bronchiolitis obliterans (popcorn lung)

Answer 19

Intraluminal polypoid plug of granulation tissue in the terminal and respiratory bronchioles
Granulation tissue= new CT caused by healing process
Causes: inhalation of foreign material (diacetyl), lung transplantation, infectious pneumonias
Symptoms: shortness of breath, wheezing, dry cough