Lung

1
Lung
2
Lung - Normal

• Bronchi cartilage
• Bronchiole no cartilage
• Respiratory bronchiole For gas exchange
• Terminal respiratory unit or Acinus
• Part of the lung distal to terminal bronchiole
• Contains
• 1. Respiratory bronchiole
• 2. Alveolar duct
• 3.Alveolar sacs/ Alveoli

1
2
3
3
Lung - Normal

• Alveoli
• Space where gas exchange takes place
• Lined by two types of cells
• Pneumocyte type I
• For gas exchange
• Very sensitive (easily damaged by toxic fumes)
• Covers about 95 of alveolar surface
• Pneumocyte type II
• Covers surface
• produce surfactant
• involved in repair after destruction of type I
  cells

4
Alveoli
EM
LM
2
1
4
3
Identify cells
5
Pulmonary alveolus Capillary
6
Lung - Pathology
7
Lung Congenital Anomalies

• Hypoplasia
• defective development of both lungs (decreased
  weight, volume, and acini)
• Most often secondary to lesions in the uterus,
  oligohydramnios, or renal abnormalities
• Foregut Cysts
• abnormal detachment of primitive foregut
• most often in the hilum or middle mediastinum
• Bronchogenic cysts are most common (others
  -esophageal, enteric), common in children and
  young adults, Mostly incidental, Rx - Surgical
  resection is curative
• Malformation (CPAM- Congenital pulmonary airway
  malformation )
• CPAM - 1 is most common with large cysts good
  prognosis
• CPAM - 2 has medium-sized cysts poor prognosis

8
Bronchogenic Cyst of Mediastinum
9
Lung Congenital Anomalies

• Sequestrations
• Lung lobes or segments without airway connection
  (NOT attached to bronchial tree)
• Blood supply from the Aortic branches (NOT from
  the pulmonary arteries)
• Clinical Significance -Mistaken for cancer (in
  adult)
• Types

10
Lung - Pathology
11

• Atelectasis
• incomplete expansion or collapse of previously
  inflated lung
• reduces oxygenation ?risk of infection
• Types
• 1. Obstructive Caused by complete obstruction of
  airways by secretions or exudates in asthma,
  chronic bronchitis, foreign bodies, neoplasms
  
• Mediastinum shifts toward affected lung
• 2. Compressive Caused by fluid or air in the
  pleural cavity
• pleural effusions, Pneumothorax, cardiac failure,
  neoplastic effusions
• Mediastenum shifts away from affected lung
• 3. Patchy Caused by loss in surfactant (neonatal
  or adult) respiratory distress syndrome (ARDS)
• 4. Contraction by local or generalized fibrotic
  changes in lung or pleura prevent full expansion

Atelectasis is often reversible ( Except one type
? )
12
Types of Atelectasis
Obstructive