Conducting Portion

Nasal cavities

Paranasal sinuses

Nasopharynx

Trachea

Bronchi

Bronchioles

Respiratory system

Respiratory Portion Respiratory bronchioles Alveolar ducts

Alveoli

Nose (nasal cavity) Nasal cavity divided into

Vestibule

Respiratory Portion Olfactory portion

Trachea

Mucosa : epithelium, LP, elastic membrane

Submucosa: BV, lymphatic nodules, tracheal

gland

Fibrocartilagenous layer

Adventitia

Lymphatic nodule

Trachea

Bronchi

Extrapulmonary bronchus Like trachea

Intrapulmonary bronchus

Bronchiole

Bronchioles are the terminal segments of the

conductive portion. At the transition from bronchi to

bronchioles the epithelium changes to a ciliated

.absent are cartilage ,cells clara epithelium, columnar

.

ventually, in

Clara cells are dome shaped cells devoid of cilia, have secretory granules in

their apex and are known

1- To secrete glycosaminoglycans that probably protect the

bronchiolar lining.

2- It is thought that they act as progenitor cells for other types of

bronchiolar epithelial cells.

Trachea Mucosa 3

Submucosa

Fibrocartilagenous

Adventitia

intra pulmonary bronchi

Mucosa no elastic

membrane less goblet cells

muscle

cartilagenous layer plates

Adventitia

Bronchiole

Mucosa simple columnar ciliated

+ clara

Muscle

adventitia

The epithelium of the alveoli is formed by two cell types: 1.Alveolar type I cells (type I pneumocytes) are extremely flattened concern with gas exchange 2.Alveolar type II cells (type II pneumocytes) are cuboidal shaped concern with secretion of pulmonary surfactant

Alveoli

Alveolar phagocytes: Alveolar macrophages remove dust particles, degrade

pulmonary surfactant or other particles, so they are

called dust cells. Then, they move along the air

passage ways and reach the bronchioles, bronchi and

trachea where they are discharged as sputum.

.