Diseases of the Respiratory System Flashcards
Main function of lungs
Gas exchange
Trachea divides into
Right and left main bronchi
Right lung vs Left lung
Right lung has 3 lobes: upper, middle, and lower.
Left lung has 2 lobes: upper and lower. The upper part has a part called lingual which is somewhat analogous to right middle lobe.
Arterial supply of the lungs
Lung has double arterial supply: pulmonary and bronchial arteries
Alveolar spaces are lined by:
2 types of epithelium: (1) type I pneumocytes, (2) type II pneumocytes
Type 1: main cell responsible for gas exchange
Type 2: produce surfactants
Defective development with dimished weight, volume, and acinar number caused by abnormalities that compress the lung or impede normal expansion in utero
Pulmonary hypoplasia (Small lungs)
Formed by abnormal detachment of primitive gut typically located in the hilum or the middle mediastinum.
Foregut cyst
Classifications of Foregut cyst based on the type of lining
- Bronchogenic - most common; lined by ciliated pseudostratified columnar epithelium
- Esophageal - presence of squamous epithelium
- Enteric - presence of intestinal glands
Refers to a discrete area of lung tissue that (1) lacks any connection to the airway system and (2) has an abnormal blood supply arising from the aorta/its branches
Pulmonary sequestration
Types of pulmonary sequestration
- Extralobar sequestrations - external to the lungs and occur anywhere in the thorax or mediastinum
- found in infants as mass lesions; assocd with other congenital anomalies - Intralobar sequestrations - occur within the lung parenchyma; typically in older children as recurrent localized infxns or bronchiectasis
Represents incomplete lung expansion or collapse of previously inflated lung producing areas of relatively airless pulmonary parenchyma leadimg to reduced oxygenation and predisposed to infection
Atelectasis
Types of atelectasis (principally encountered in adults)
- _____________ - caused by excessive secretions, foreign body aspiration and/or bronchial neoplasms
- mediastinum shift towards the atelectatic lung - _____________ -significant vol of fluid accummulates within the pleural cavity
- mediastinum shift away from the atelectatic lung - ____________ - occurs when focal or generalized pulmonary or pleural fibrosis prevents full lung expansion
- irreversible
- Resorption atelectasis - caused by excessive secretions, foreign body aspiration and/or bronchial neoplasms
- mediastinum shift towards the atelectatic lung - Compressive atelectasis -significant vol of fluid or air accummulates within the pleural cavity
- mediastinum shift away from the atelectatic lung - Contraction atelectasis - occurs when focal or generalized pulmonary or pleural fibrosis prevents full lung expansion
- irreversible
Leakage of excessive insterstitial fluid which accummulates in alveolar spaces resulting from either increased hydrostatic pressure or increased capillary permeability
Pulmonary edema
Left-sided congenital heart failure leads to an increased hydrostatic pressure. Capillaries engorge with granular pink precipitates along alveolar spaces.
Brown induration: Lung becomes brown and firm due to interstitial fibrosis and presence of heart failure cells
Hemodynamic pulmonary edema
Noncardiogenic pulmonary edema
Due to injury to the alveolar septa (microvascular or epithelial injury)
Production of inflam exudate, leaks into the interstitial space
Overshadowed by mx of infections
Edema caused by microvascular injury
Aka noncardiac pulmonary edema
Char’d by abruot hypoxemia and diffuse pulmonary infiltrates in the absence of cardiac failure
Acute lung injury
Manifestation of severe ALI
Acute respiratory distress syndrom (ARDS)
Histologic manifestations of ALI and ARDS
Diffuse alveolar damage (DAD)
Widespread ALI of unknown origin/etiology
Acute interstitial pneumonia
A chronic obstructive airway disease char’d by irreversible enlargement of airspaces distal to the terminal bronchioles, with alveolar wall destruction and minimal fibrosis
Emphysema
4 types of Emphysema accdg to its anatomic distribution
- ____________________ - destruction and enlargement of central or proximal parts of the respiratory unit
- most common (in smokers, with chr bronchitis) - ____________________ - uniform destruction and enlargement of the acinus in the lower basal zones and ant margins
- assocd with a1-antitrypsin - ____________________ - distal acinus; typically, near the pleura and adj to fibrosis or scars
- char’c finding: multiple, continuous enlarged airspaces forming cyst-like structures
- underlies spontaneous pneumothorax - ____________________
- irregular emphysema
- Centriacinar (centrilobular) Emphysema - destruction and enlargement of central or proximal parts of the respiratory unit
- most common (in smokers, with chr bronchitis) - Panacinar (panlobular) emphysema - uniform destruction and enlargement of the acinus in the lower basal zones and ant margins
- assocd with a1-antitrypsin - Distal acinar (paraseptal) emphysema - distal acinus; typically, near the pleura and adj to fibrosis or scars
- char’c finding: multiple, continuous enlarged airspaces forming cyst-like structures
- underlies spontaneous pneumothorax - Airspace enlargement with fibrosis
- irregular emphysema
Other forms of Emphysema
__________________
- dilation of alveoli but no destruction of alveolar walls
- due to loss of lung substance
- no relation to smoking
__________________
- lung expands due to air trapped within
- subtotal obstruction by a tumor or foreign object
__________________
- large supleural bled or bullae occuring in any form of emphysema
- may give rise to pneumothorax during ruptuepre of bullae
__________________
- entrance of air into CT stroma of lung, mediastinum, or SCT
Compensatory hyperinflation
- dilation of alveoli but no destruction of alveolar walls
- due to loss of lung substance
- no relation to smoking
Obstructive overinflation
- lung expands due to air trapped within
- subtotal obstruction by a tumor or foreign object
Bullous emphysema
- large supleural bled or bullae occuring in any form of emphysema
- may give rise to pneumothorax during ruptuepre of bullae
Interstitial emphysema
- entrance of air into CT stroma of lung, mediastinum, or SCT
Persistent cough with sputum production for at least 3 months in at least 2 consecutive years but in the absence of any other identifiable causes
Most important risk factor: cigarette smoking
Dominant pathologic features: mucus hypersecretion, persistent inflam
Leads to COPD
Chronic bronchitis
Chronic immunologic disorder marked by episodic bronchoconstriction due to icnreased airway sensitivity to a variety of stimuli
Inflammation of bronchial walls, increased mucus secretion
Manifested by recurrent episodes of wheezing, breathlessness, chest tightness, and cough at night or early morning.
Asthma
Destruction of smooth muscle and elastic tissue by chronic necrotizing infxns leading to permanent dilatation of bronchi and beonchioles
Char’c symptom: cough and expectoration of copious amount of purulent sputum
Assocd with different conditions
Bronchiectasis
Heterogenous group pf d/o chard by inflam and pulmonary iterstitial tissue fibrosis involving alveolar walls
Classic fxn’l abns: rdxns in diffusion capacity, lung volume and lung compliance
Honey-combed lung
Chronic diffuse interstitial (Restrictive) dses
Disorder of unknown cause chrad by progressive pulmonary interstitial fibrosis and rspiratory failure
Idiopathic pulmonary fibrosis (IPF)
Formerly called bronchiolitis obloterans organizing pneumonia (BOOP)
Cough and dyspnea w latchy subpleural or peribronchial areas of airspace consolidation radiographically
Histo: loose fibrous tissue plugs (Masson bodies) w/n bronchioles, alveolar ducts, and alveoli; no interstitial fibrosis or honeycombing
Cryptogenic Organizing pneumonia
