Respiratory Histology: Structure and Function

Question 1

1. What is the extrathoracic (upper) airway comprised of?

Answer 1

• the nose
• nasal cavity
• pharynx
• larynx
• upper trachea

Question 2

what is the intrathoracic (lower) airway comprised of?

Answer 2

• The lower trachea
• left and right main bronchi
• multiple bronchial generations
• lungs

Question 3

3. What are nasal vestibules lined by?

Answer 3

keratinized stratified squamous epithelium

Question 4

4. What are the modified hairs in nasal vestibules called?

Answer 4

Vibrissae

Question 5

5. Describe the membrane transition as you go further into the nasal vestibules

Answer 5

transition from keratinised stratified squamous epithelium to pseudo stratified columnar ciliated epithelium with goblet cells

Question 6

what is pseudo stratified columnar ciliated epithelium with goblet cells also known as?

Answer 6

Respiratory epithelium

Question 7

6. What are the floors and walls of the nasal cavity covered with and what is presence throughout the mucous membranes

Answer 7

• covered with respiratory epithelium
• seromucous glands dispersed throughout the mucous membranes

Question 8

7. What is the roof of the nasal cavity covered with

Answer 8

• covered with respiratory epithelium and olfactory epithelium motile cilia

Question 9

what is another name for motile cilia

Answer 9

olfactory epithelium

Question 10

8. Which epithelium is less vascularized: Olfactory or respiratory epithelium?

Answer 10

olfactory epithelium

Question 11

9. What type of epithelium is found in the larynx

Answer 11

laryngeal mucosa

Question 12

what 4 things are observed between the lamina propria to the end of the laryngeal ventricle

Answer 12

• goblet cells
• seromucous glands
• lymphatic nodules
• adipocytes

Question 13

describe the transition of the epithelium after the lower border of the ventricle

Answer 13

• changes to become a non-keratinised stratified squamous epithelium covering the true vocal cords

Question 14

what are 3 features of the lamina propria at the true vocal cords

Answer 14

• avascular
• thin
• lacks glands and lymphatic tissue

Question 15

describe the transition of the epithelium between the larynx and the trachea

Answer 15

• transitions to a pseudo stratified ciliated columnar epithelium

Question 16

what cartilage of the larynx is the trachea attached to by the cricothyroid membrane

Answer 16

is attached by the cricoid cartilage

Question 17

what type of tube is the trachea and how is it completed posteriorly?

Answer 17

• mucocartilagenous tube
• completed posteriorly by smooth trachealis muscle

Question 18

12. What does mucus in the lumen of the trachea do?

Answer 18

Traps particles and bacteria

Question 19

13. What does cilia do in the lumen of trachea?

Answer 19

Pushes particles and bacteria back up the trachea with rhythmic movements

Question 20

14. What does the lower trachea do at the carina?

Answer 20

bifurcates at the carina to form a left and right primary bronchus

Question 21

15. What type of cartilage surrounds the bronchi and what does it do

Answer 21

• hyaline cartilage C rings surround bronchi
• function is to keep the bronchi open

Question 22

what epithelium surrounds the lumen of the bronchi

Answer 22

respiratory epithelium

Question 23

17. What surrounds the lamina propria in the bronchi and what does it do

Answer 23

• a thin layer of smooth muscle
• separates it from the submucosal layer

Question 24

18. What is the difference between cartilage in the trachea and the primary bronchi?

Answer 24

in primary bronchi cartilage is discontinuous whereas in the trachea it is a continuous C shape

Question 25

19. What are the 3 types of cell found in alveoli

Answer 25

- Type I Pneumocytes - Type II Pneumocytes - Alveolar Macrophages

Question 26

20. Give 3 features of Type I pneumocytes

Answer 26

- squamous alveolar cells - covers 95% of surface area - provides an ideal environment for gases to pass to and from adjacent capillary beds

Question 27

21. Give 3 features of Type II pneumocytes

Answer 27

- covers 5% of surface area - cuboidal alveolar cells - enables the production of surfactant to repair the alveolar epithelium when squamous cells are damaged

Question 28

22. What are alveolar macrophages

Answer 28

dust cells with monocytes origins that perform a phagocytic function

Question 29

23. What 2 things does the respiratory membrane contain in the alveoli?

Answer 29

contains: - squamous alveolar cell - squamous capillary endothelial cell - the underlying basement membrane

Question 30

what separates alveolar air from blood

Answer 30

respiratory membrane

Question 31

24. What do type II pneumocytes secrete and by what process

Answer 31

secrete surfactants via exocytosis

Question 32

25. How does the epithelium change from the trachea to the terminal bronchi

Answer 32

Pseudostratified columnar ciliated cells to simple cuboidal cells

Question 33

26. Outline the 6 defence mechanisms of the respiratory system

Answer 33

1. mucus layer 2. Alveolar macrophages 3. Secretory IgAs 4. Alveolar epithelial cells 5. Lysozyme, lactoferrin or peroxide 6. Lymphocytes, neutrophils, immunoglobulins and opsonins

Question 34

27. How does the mucus layer act as a defence mechanism of the respiratory system

Answer 34

traps pathogens and particles stopping them from reaching lungs

Question 35

28. How do the alveolar macrophages act as a defence mechanism of the respiratory system

Answer 35

type of WBC that tracks deposited particles, adheres to them, then ingests and digests them.

Question 36

29. what 2 ways do secretory IgAs act as a defence mechanism of the respiratory system

Answer 36

1. neutralises toxins and viruses 2. blocks the entry of bacteria across the epithelium

Question 37

30. How do alveolar epithelial cells (type I & II pneumocytes act as a defence mechanism of the respiratory system

Answer 37

recruits inflammatory cells by releasing arachidonic acid derivates

Question 38

31. How do lysozymes act as a defence mechanism of the respiratory system.

Answer 38

- lysozyme degrades a glycosidic linkage of bacterial membrane peptidoglycans

Question 39

how does lactoferrin act as a defence mechanism of the respiratory system

Answer 39

- An Iron-binding protein that reduces the availability of elemental iron.

Question 40

how does peroxide act as a defence mechanism of the respiratory system

Answer 40

- acts on thiocyanate ions or produce oxygen radicals that are bacteriostatic or bactericidal.