Histology

Question 1

Nasal Cavity (4)

Answer 1

Warms, moistens and filters inspired air with the aid of conchae
Roof contains olfactory epithelium
Vestibule (initial part) is lined with by keratinized stratified squamous epithelium
Deeper in the nasal cavity the lining changes to Respiratory epithelium

Question 2

Respiratory Epithelium characteristics (6)

Answer 2

Non-keratinized pseudostratified ciliated columnar epithelium with goblet cells

Question 3

Parts of nasal cavity with stratified squamous epithelium (4)

Answer 3

Vestibule
Oropharynx
Laryngophayrnx
Esophagus

Question 4

Parts of nasal cavity with respiratory epithelium (4)

Answer 4

Conchae
Nasopharynx
Larynx
Trachea

Question 5

Lamina Propria (3)

Answer 5

Band of loose connective tissue underneath respiratory epithelium
Contains seromucous glands and thin-walled venous sinuses
Can be engorged with blood and ‘block’ nose especially during allergy

Question 6

Does the oropharynx, anterior surface and upper part of posterior surface of epiglottis have keratinized/non-keratinized stratified squamous epithelium

Answer 6

Non-keratinized

Question 7

Larynx

Answer 7

Walls of cartilage and muscles are lined with respiratory epithelium except the vocal folds due to adhesion

Question 8

Trachea (3)

Answer 8

Contains 15-20 ‘C’ shaped cartilages
Open side of ‘C’ shaped cartilage is spanned by fibroelastic tissue and smooth muscle
Wall is made of respiratory epithelium, basal lamina, lamina propria with elastic fibres and submucosa with seromucous glands

Question 9

Bronchus (2)

Answer 9

Contains irregularly shaped cartilage plates
Wall is made of respiratory epithelium, lamina propria, muscularis with a ring of smooth muscle and submucosa with adipose tissue and seromucous glands

Question 10

Bronchioles (4)

Answer 10

Diameter less than 1 mm
Lack cartilage and glands but initial portion may have goblet cells
Epithelium decreases in height from columnar to cuboidal down the respiratory tree
Lamina propria contains smooth muscle, elastic and collagenous fibres

Question 11

Smooth muscle in bronchioles (2)

Answer 11

Responds to parasympathetic innervation and histamine by contracting bronchiole diameter
Plays a significant role in asthma and allergic attacks

Question 12

Terminal bronchioles (3)

Answer 12

Smallest bronchioles lacking gas exchange
Branches out to respiratory bronchioles
Lined with cuboidal ciliated epithelium containing Club cells

Question 13

Roles of Club cells (4)

Answer 13

Stem cells
Detoxification
Immune modulation
Surfactant production

Question 14

How does the respiratory tree from the terminal bronchioles and above obtain O2 and nutrients

Answer 14

Via bronchial arterial above the segmented bronchi

Question 15

Alveoli

Answer 15

Lined by epithelium consisting of type 1 and 2 alveolar cells

Question 16

Type 1 alveolar cells (2)

Answer 16

Simple squamous epithelium that lines 90% of surface

Provides barrier of minimal thickness for gas permeability

Question 17

Type 2 alveolar cells (4)

Answer 17

Polygonal shape
Covered with microvilli
Cytoplasm contains lamellar bodies containing surfactant
Surfactant reduces surface tension and prevents alveoli collapse at the end of expiration

Question 18

Alveolar macrophages (Dust cells) (3)

Answer 18

Free cells in septa or migrating over luminal surfaces
Phagocytoses inhaled fine particles
They either move up the bronchial tree via ciliary action or move in the septal connective tissue where they will remain

Question 19

Air blood barrier (3)

Answer 19

Made of 3 cell types
Type 1 alveolar, endothelial and basal lamina cells
It is as thin as 200-600 nm

Question 20

Visceral Pleura (2)

Answer 20

Made of outer simple squamous epithelium called mesothelium, fibrous and elastic connective tissue
Faces parietal pleura where the pleura cavity contains lubricating fluid