Lecture 21: Pulmonary histology

Question 1

Respiratory mucosa consists of

Answer 1

Pseudostratified ciliated columnar epithelium
Lamina propria- thin layer of loose CT
Submucosa- dense irregular CT

Question 2

Nares contain

Answer 2

Stratified squamous epithelium continuous with epidermis

Sebaceous, sudoriferous glands and hair follicles

Question 3

Olfactory epithelium is

Answer 3

Pseudostratified columnar epithelium without goblet cells
No basement membrane
Sustenacular cells w/pigment granules
Basal cells w/pigment granules

Question 4

Olfactory cells

Answer 4

Bipolar neurons
Apical end projects into nasal cavity and contains nonmotile cilia w/g-protein linked odor receptors
Basal end extends as unmyelinated axon to mitral cells in the olfactory bulb
Olfactory cells senesce and are replaced from basal cells

Question 5

Olfactory glands of Bowman

Answer 5

Located in the lamina propria
Secrete odorant-binding protein
Odorant-binding protein binds to odorant molecules in nasal cavity

Question 6

Nasopharynx mucosa consists of what epithelium

Answer 6

Respiratory epithelium

Question 7

Waldeyers ring

Answer 7

Ring of lymphoid tissue around nasopharynx

Includes tonsils and adenoids

Question 8

Epiglottis lingual surface

Answer 8

Covered with stratified squamous epithelium

Lamina propria with loose CT and elastic fibers

Question 9

Epiglottis pharyngeal surface

Answer 9

Covered with pseudostratified ciliated epithelium

Lamina propria with tubuloacinar seromucous glands

Question 10

Core of epiglottis consists of

Answer 10

Elastic cartilage

Question 11

False vocal cords

Answer 11

Covered with pseudostratified ciliated and stratified squamous epithelium
Lamina with seromucous glands

Question 12

True vocal cords

Answer 12

Covered with stratified squamous epithelium

Lack seromucous glands in lamina propria

Question 13

Epithelium of larynx

Answer 13

Respiratory epithelium (pseudostratified ciliated columnar)
Stratified squamous

Question 14

Cartilage of larynx

Answer 14

Hyaline cartilage- thyroid, cricoid, arytenoids

Elastic cartilage- corniculates, cuneiforms, tips of arytenoids, epiglottis

Question 15

Muscle in larynx

Answer 15

Skeletal muscle

Question 16

Mucosa of trachea

Answer 16

Respiratory epithelium w/thick basement membrane

Lamina propria w/delicate FECT and lymphatic tissue

Question 17

Submucosa of trachea

Answer 17

Contains many seromucous glands

Question 18

Adventitia of trachea

Answer 18

16-20 horseshoe-shaped cartilages interconnected by FECT

Mixed glands and capillaries

Question 19

Trachea divides into two

Answer 19

Bronchi

Question 20

Each primary bronchus divides into

Answer 20

Three (to right lung) or two (to left lung) secondary bronchi, also referred to as lobar bronchi

Question 21

As the bronchi become smaller, there is a

Answer 21

Decrease in the height of the epithelium, decrease in cartilage and glands, and an increase in the proportion of elastic fibers and smooth muscles

Question 22

Mucosa of bronchi

Answer 22

Similar to trachea
May have mucosal folds due to smooth muscle
Elastic fibers are prominent

Question 23

Submucosa of bronchi

Answer 23

Characterized by loose CT and lymphatic tissue

Contains mixed glands and mucous glands

Question 24

Adventitia of bronchi

Answer 24

Contains hyaline cartilage plates surrounded by dense FECT

Question 25

Characteristics of bronchioles

Answer 25

Absence of cartilage and glands
Sparse goblet cells
Large amounts of smooth muscle tissue
Epithelium transitions from ciliated columnar with few goblet cells to ciliated cuboidal with no goblet cells (terminal bronchioles)

Question 26

Characteristics of respiratory bronchioles

Answer 26

Epithelium of low columnar to low cuboidal
Cilia present only in larger respiratory bronchioles
No goblet cells
Wall consists of smooth muscle within FECT
May have a few alveolar outpocketings

Question 27

Alveolar ducts

Answer 27

Continuations of respiratory bronchioles
Cone shaped
Squamous epithelium
Wall consists of smooth muscle within FECT

Question 28

Type I alveolar cells (pneumocytes)

Answer 28

Less numerous than type II pneumocytes
Cover largest surface area (95% of alveolar surface)
Very thin cytoplasm
Tight junctions connect with other Type I cells

Question 29

Type II alveolar cells (pneumocytes)

Answer 29

Cuboidal or rounded
Serve as stem cells for type I and type II pneumocytes
Produce phospholipid-protein surfactant that coats alveolar walls

Question 30

Pores of Kohn

Answer 30

Openings between adjacent alveoli

Question 31

Goblet cells

Answer 31

Mucous secreting cells

Also stem cells; can replace other cells of epithelium

Question 32

Neuroendocrine cells

Answer 32

May be associated with sensory reception and are more prevalent in infants
Release catecholamines

Question 33

Surfactant

Answer 33

Secreted by Clara cells and type II alveolar cells
Reduces surface tension on alveolar cells
Phagocytized by type II alveolar cells

Question 34

Dipalmitoyl phsophatidycholine (lecithin)

Answer 34

Found in lamellar bodies in Type II alveolar cells
Secreted from apical domain
Combines with proteins from Clara cells

Question 35

Clara cells

Answer 35

Only found in broncholes
Number of Clara cells increases as ciliated columnar cells decrease
Apical surface bulges into lumen of airway
Secrete lipoprotein that prevents collapse of terminal bronchioles during exhalation
Contain abundant SER

Question 36

Dust cells

Answer 36

Macrophages in respiratory tract

Question 37

Dust cell relation to CHF

Answer 37

In CHF, fluid containing the breakdown products of hemoglobin leak into alveolar spaces and are phagocytized by dust cells
The iron containing dust cells are referred to as heart failure cells

Question 38

Components/function of blood air barrier

Answer 38

Thin capillary endothelium (continuous)
Thin epithelium of pneumocyte
Intervening basil lamina produced by both cell types
Permits gas exchange but does not allow fluids or cells to enter alveoli