The last lecture on respiratory system

Ramray Bhat

Ramray@iisc.ac.in

On the matter of the Clara cells

Bronchiolar exocrine cells

Immune, protective and progenitory properties

Also called Club cells and why?

Part of uterus, kidney prostate

Emphysema

Environmental/genetic (α1 antitrypsin deficiency

Dead air

Poor exchange

Emphysema

Chronic obstructive pulmonary disease

A combination of chronic bronchitis and emphysema

Definition of emphysema: morphological

Definition of chronic bronchitis: clinical features such as chronic

and recurrent cough and excessive mucus secretion

Both diseases have slightly different locales: emphysema occurs

more in acinus and chronic bronchitis in the bronchi

Reason for coexistence

This is because the major cause, cigarette smoking, especially long-

term, heavy tobacco exposure is common to both disorders.

In view of their propensity to coexist, emphysema and chronic

bronchitis often are clinically grouped together under the rubric of

chronic obstructive pulmonary disease (COPD).

The primarily irreversible airflow obstruction of COPD distinguishes it

from asthma, which, as described later, is characterized largely by

reversible airflow obstruction.

normal alveoli emphysemaCOPD - emphysema

Barrel chest, dyspnea, pink puffer, a problem of expiration

Defined by the occurrence of a persistent productive cough for at least 3

consecutive months in at least 2 consecutive years. In early stages of the

disease, the productive cough raises mucoid sputum.

COPD – chronic bronchitis

bronchus chronic bronchitis

Hypoxia, blue bloater

Obstructive and non

obstructive causes

Asthma is a chronic inflammatory disorder of the airways with recurrent episodes of wheezing, breathlessness, chest tightness, and cough, particularly at night and/or early in the morning.

The hallmarks of the disease are1. intermittent and reversible airway obstruction, 2. chronic bronchial inflammation with eosinophils,3. bronchial smooth muscle cell hypertrophy and hyperreactivity, and 4. increased mucus secretion.

Atopic (allergic rhinitis and eczema) or non atopic

Bronchial asthma

An attack of asthma is characterized by severe dyspnea with wheezing; The victim labors to get air into the lungs and then cannot get it out, so that there is progressive hyperinflation of the lungs with air trapped distal to the bronchi, which are constricted and filled with mucus and debris.

Histopathologic changes in bronchial asthma

Bronchial asthma

Gross pathology: overdistended and overinflated lungssmall areas of atelectasis. occlusion of bronchi and bronchiolesby thick, tenacious mucous plugs.

Bronchial asthma contd

Lung cancer

Introduction to cancer

Terminologies (cancer, neoplasm, tumor, benign malignant)

(parenchyma, stroma)

(benign: fibroma, chondroma, adenoma, cystadenoma)

Malignant: (sarcoma, carcinoma, adenocarcinoma, mixed tumor)

Lungs are the frequent sites of metastases from extrathoracic cancers,

Primary lung cancer is common 95% of primary lung tumors are carcinomas 5% includes carcinoids, mesenchymal malignancies, lymphomas,and a few benign lesions.

The most common benign tumor is a spherical, small (3 to 4 cm), discrete “hamartoma”: coin lesion on chest radiographs. It consists mainly of mature cartilage, admixed with fat, fibrous tissue, and blood vessels

Lung cancers

Types of carcinoma:Adenocarcinoma (NSCLC)Squamous cell carcinoma (NSCLC) (smoking)Small cell carcinoma (smoking)Large cell carcinoma (NSCLC)

Squamous cell carcinoma of bronchi

Keratinized pearls

Atelectasis

normal

SqCC

Small cell lung carcinoma

Small deeply basophilic cells uniformly present within parenchymaRoundish cells, big nuclei, scant cytoplasm, mitotic foci

Necrotic foci

More aggressive, detected after the spread unlike NSCLC

Hoarseness, congestion, chronic cough common primary symptoms