Histology

Question 1

What is the purpose of the extensive area in the nasal cavity?

Answer 1

1. warming
2. moistening
3. filtering
   the inspired air

Question 2

What is the nasal cavity lined by?

Answer 2

• initial part of the nasal cavity is lined by keratinised stratified squamous epithelium
• further into the airway the keratin is lost
• it changes to pseudo stratified ciliated columnar epithelium

Question 3

What is the oropharynx lined by?

Answer 3

• non keratinised stratified squamous epithelium

Question 4

What is the anterior surface and upper part of the posterior surface of the epiglottis?

Answer 4

• non keratinised stratified squamous epithelium

Question 5

what is the structure of the larynx?

Answer 5

• the walls are made up go cartilage and muscles with respiratory epithelium lining its surfaces
• with the exception of the vocal folds which are covered with stratified squamous epithelium

Question 6

describe the structure of the trachea?

Answer 6

• contains 15-20 ‘C’ shaped cartilages

- The open side of the C is spanned fibroelastic tissue and smooth muscle

Question 7

Describe the lining of the trachea?

Answer 7

• lining of respiratory epithelium
• backed by a basal lamina, a lamina propria of abundant elastic fibres and a submucosa of connective tissue that includes numerous seromucous glands

Question 8

When do bronchi become bronchioles?

Answer 8

• when the cartilage is lost and the airway is about 1mm in diameter

Question 9

What are terminal bronchioles?

Answer 9

• smallest bronchioles that lack respiratory function

Question 10

what are the roles of club cells in the terminal bronchioles?

Answer 10

• stem cells
• detoxification
• immune modulation
• surfactant production

Question 11

What is the role and structure of type 1 alveolar cells?

Answer 11

• simple squamous epithelium

- they provide a barrier of minimal thickness that is permeable to gases

Question 12

What is the role and structure of type 2 alveolar cells?

Answer 12

• polygonal in shape
• free surface covered by microvilli
• cytoplasm displays membrane bound lamellar bodies which contain surfactant

Question 13

What is the role of surfactant?

Answer 13

reduces the tendency of the alveoli to collapse at the end of expiration

Question 14

What is the role of alveolar macrophages?

Answer 14

• phagocytose inhaled particles

- migrate up the bronchial tree to the pharynx where they are swallowed

Question 15

describe the structure of the visceral pleura

Answer 15

• outer layer of simple squamous epithelium (mesothelium)

- this is backed by layers of fibrous and elastic connective tissue