Chapter 22: Mechanisms of Gas Exchange

Vocabulary flashcards covering the mechanisms of gas exchange in humans, fish, and insects based on Chapter 22 lecture notes.

Gas exchange

The interchange of $O_2$ and $CO_2$ between an organism and its environment which provides $O_2$ for cellular respiration and removes the waste product $CO_2$.

Three phases of gas exchange

The processes in humans and other animals with lungs consisting of breathing, transport of gases by the circulatory system, and exchange of gases with body cells.

Respiratory surfaces

The parts of an animal where gas exchange occurs; they must be thin and moist for the diffusion of $O_2$ and $CO_2$.

Gills

Respiratory organs adapted for aquatic environments that absorb $O_2$ dissolved in water.

Ventilation

The flow of water (or air) over the respiratory surface which enhances gas exchange.

Countercurrent exchange

The transfer of a substance, such as oxygen, between two fluids flowing in opposite directions, helping to enhance gas exchange in fish.

Tracheal system

A system in insects with respiratory surfaces at the tips of tiny branching tubes that transports $O_2$ directly to body cells and reduces evaporative water loss.

Tracheae

The largest tubes in an insect's tracheal system that connect to external openings spaced along the body.

Diaphragm

A muscle that separates the abdominal cavity from the thoracic cavity and helps ventilate the lungs in mammals.

Nasal cavity

The area where air is inhaled through the nostrils, filtered by hairs and mucous surfaces, warmed, humidified, and sampled for odors.

Mammalian air pathway

The route inhaled air follows: pharynx, larynx, trachea, bronchi, bronchioles, and finally the alveoli.

Surfactants

Specialized secretions that prevent the moist surfaces of the alveoli from sticking shut.

Mucus and cilia

Structures in the respiratory passages that protect the lungs by trapping and moving contaminants.

Alveoli

The final destination of inhaled air in the mammalian lung where gas exchange occurs.