Histology

Question 1

Features of bronchioles

Answer 1

diameter >1mm
Clara cells
Cilia
No glands
Helically arranged smooth muscles
Terminal bronchioles --> respiratory bronchioles --> alveolar ducts --> alveoli

Question 2

Clara cells

Answer 2

non-ciliated columnar cells
unique to bronchioles
detoxify inhaled noxious substances (e.g. NO)

Question 3

Features of cilia in the trachea

Answer 3

Goblet cells secreting mucus
Do not contain smooth muscle
normal feature of goblet cells/stem cells
sweep particles in a synchronized fashion
axoneme with 9+2 microtubular arrangement

Question 4

Epithelial lining of respiratory tract

Answer 4

Pseudostratified changes to simple columnar then simple cuboidal in bronchioles
Then simple squamous in the alveoli

Question 5

Olfactory epithelium contains

Answer 5

Bowman’s glands

Question 6

Features of trachea

Answer 6

Pseudostratified ciliated epithelium
Goblet cells interspersed
Outer anterolateral aspect: 16-20 crescent-shaped rings of hyaline cartilage
Posterior surface: ends of cartilages are spanned by fibrous membranes containing smooth muscle = trachealis muscle
Lamina propria richly vascularized, contains small seromucous glands

Question 7

Composition of alveolar wall

Answer 7

Type 1 epithelium: covers 95% but 40% of cells

Type 2: covers 5% but 60% of cells

Question 8

Pathway of oxygen from air in alveolus –> blood

Answer 8

1. surfactant
2. cytoplasm of type I pneumocyte
3. basal lamina of type I pneumocyte
4. basal lamina of endothelium
5. cytoplasm of endothelium
6. blood plasma

Question 9

Multilamellar bodies are a characteristic of

Answer 9

type 2 pneumocytes

Question 10

Alveolar macrophages :

Answer 10

originate in bone marrow
engulf micro-particles
derived from blood monocytes