Respiratory System

Why must all living organisms exchange gases with the environment?

To maintain survival and support respiration or remove waste.

Why is oxygen required for aerobic respiration?

To produce sufficient quantities of ATP.

Why must carbon dioxide be removed from the body?

It is a waste product that alters blood pH.

What does the mnemonic SMART stand for regarding gas exchange surfaces?

Surface area, Moist, Absorptive, Rich blood system, Thin tissue layer.

Through what physical process does gas exchange occur across respiratory surfaces?

Simple diffusion.

Through what pathway does air travel from the nose or mouth to the alveoli?

Trachea, bronchi, bronchioles, and alveoli.

What is the primary function of Type I pneumocytes in the alveoli?

To mediate gas exchange across a thin diffusion distance.

What is the primary function of Type II pneumocytes in the alveoli?

To secrete pulmonary surfactant that reduces surface tension.

Why is pulmonary surfactant necessary in the alveoli?

To reduce surface tension and prevent alveolar collapse.

According to Boyle's law, how are pressure and volume related in the lungs?

Pressure is inversely proportional to volume.

How does the diaphragm move during inspiration?

It contracts and flattens to increase thoracic volume.

What action do external intercostal muscles perform during inhalation?

They contract, pulling the ribs outwards.

What happens to the diaphragm during expiration?

It relaxes and curves upward, decreasing thoracic volume.

What does a spirometer measure in human ventilation?

The volume or speed at which air is exchanged.

What major factor causes alveolar walls to lose elasticity in emphysema?

Cigarette smoking and chemical irritants.

Which enzyme breaks down elastin fibers in the alveolar walls during emphysema?

Elastase secreted by phagocytes.

What are primary risk factors associated with lung cancer?

Tobacco smoke, pollution, asbestos, and radiation.

What is tidal volume in lung capacity measurements?

The amount of air exchanged via a normal breath.