Functional Histology Resp Syst session1

Question 1

Respiratory portion and epithelial changes

Answer 1

Respiratory bronchioles(after terminal) to alveoli

Respiratory bronchioles
Alveolar ducts
* Alveoli *
(All intrapulmonary)

ALL simple cuboidal epithelium with a few scattered cilia and club/ Clara cells bar alevoli*: simple squamous/ type 1 + septal type 2 pneumocytes

Question 2

Conducting portion and epithelial changes

Answer 2

extrapulmonary
Nasal cavity 
Pharynx 
Larynx 
Trachea
Primary bronchi 

Intrapulmonary
Secondary bronchi
Bronchioles
* Terminal bronchioles *

ALL pseudostratified ciliated columnar epithelium with goblet cells bar TB*: simple columnar with cilia and club/ Clara cells but no goblet

Question 3

Layers of the trachea

Answer 3

10cm long, 2.5 cm wide

Adventitia

Hyaline cartilage ring

Submucosa with seromucous glands

Lamina propria with many elastin fibres

pseudostratified ciliated columnar epithelium

Mucous membrane

Lumen

Trachealis muscle posterior

Divides into 2 primary bronchi in mid-thorax, same histology bar cartilage rings and spiral muscle completely encircle lumen

Question 4

Contents of secretions and the epithelium and submucosal glands of the trachea and bronchi

Answer 4

Much s, water, serum proteins, lysozyme, antiproteases, lymphocytes contribute immunoglobulins

Question 5

Secondary and tertiary bronchi and bronchioles structure

Answer 5

Similar to primary bronchi/ trachea except cartilages arranged as irregular crescent plates or islands rather than rings

Bronchioles no glands or cartilage

Question 6

Function of club/ Clara cells

Answer 6

Secrete a surfactant lipoprotein which prevents the walls sticking together during expiration

Question 7

Cells of the alveolus

Answer 7

Type 2 pneumocytes secrete surfactant (cuboidal epithelium)

Type 1 permits gas exchange (squamous epithelium)

Macrophages phagocytise dust & microbes

Question 8

Emphysema

Answer 8

Destruction alveolar walls and permanent enlargement of air spaces

From smoking or alpha 1- antitrypsin deficiency

Bronchioles collapse, air becomes trapped can’t exhale

Question 9

Pneumonia

Answer 9

Inflammation of the lung bacteria, lungs consolidate as alveoli fill with inflammatory cells

Most common: streptococcus pneumoniae

Also: haemophilus influenza, staphylococcus aureus, legionella pneumophila, mycoplasma pneumoniae