ToxicologyThe Respiratory system

Toxicological perspectives

Direct target of toxicity from exposure to many airborne chemicals.

Provides an early warning detection system.Provides an exposure pathway for systemic exposure

to many toxicants.Is an important organ system for many xenobiotic

biotransformation.

Respiratory system

The average adult inhales approximately 12kg of air daily.

Incidents like the accidental release of 40 tons of methyl isocynates in Bhopal, India.

Handling and milling grain releases atmospheric dust that may provokes asthmatic attack.

Respiratory system play role in the recognition, metabolism, detoxification, elimination of xenobiotics

Lungs

The human lungs are the organs of respiration in humans.

Humans have two lungs, with the left being divided into two lobes and the right into three lobes.

Together, the lungs contain approximately 2,400 kilometers of airways and 300 to 500 million alveoli, having a total surface area of about 70 square meters in adults.

Each lung weighs 1.1 kilograms therefore making the entire organ about 2.3 kilograms.

Functional division of respiratory systemNasopharyngealTracheobronchialPulmonary

Mechanism action of aerosolized toxins

Inhalation of aerosolized toxin opening of sodium channels

release of neurotransmitters autonomic nerve ending

airway smooth muscles depolarization

contraction

Systemic toxicities through respiratory exposure

Carcinogens Poly aromatic hydrocarbon, vinyl chloride.

Hematoxicities Arsine, nitrobenzene, CO.

Nephrotoxicites Heavy metals, chloroform,CCl4.

Hepatotoxicites CCl4, ethanol.

CNS toxicants Acrylamide, mercury, acetone

Asphyxiants CO,N2,CH4.

Irritants NH3,NO2,SO2.

Nomenclature of airborne toxicants

GasesVaporAerosolsDustsFumesSmokeFogSmog

Respiratory system injury

Irritative or inflammatoryBronchoconstructiveFibroticOncogeneticNecrotic

Air pollutants

OZONE(O3) Sulfur dioxide(SO2) Nitrogen dioxide(NO2) Carbon monoxide (CO) Lead (Pb)

Asbestosis

Chronic Obstructive Pulmonary Disorder (COPD)

Centrilobular emphysema

Squamous cell carcinoma of the lung

Normal Chest X-Ray and Lung

Chest X-Ray and Diseased Lung

Bronchoscope