Gas Exchange Flashcards
What is gas exchange?
The process by which organisms exchange gases (e.g., oxygen and carbon dioxide) with their environment, usually via diffusion across specialized surfaces.
What is the importance of a large surface area in gas exchange?
A large surface area increases the rate of diffusion, allowing more gases to be exchanged in a given time.
What is the relationship between surface area and volume in gas exchange?
As an organism’s size increases, its surface area: volume ratio decreases, meaning it needs specialized structures for efficient gas exchange.
Why is a thin surface important for gas exchange?
A thin surface shortens the diffusion distance, which increases the rate of gas exchange.
What does a steep concentration gradient do in gas exchange?
A steep concentration gradient (high difference in gas concentration) allows gases to diffuse more quickly, enhancing the efficiency of gas exchange.
How do insects exchange gases?
Insects have a tracheal system consisting of spiracles (pores), tracheae (tubes), and tracheoles (smaller tubes) that deliver oxygen directly to tissues.
What is the function of spiracles in insects?
Spiracles are small openings in the exoskeleton that control the flow of air in and out of the tracheal system, helping regulate water loss and oxygen intake.
How does abdominal pumping in insects aid gas exchange?
Abdominal pumping creates pressure changes that push air in and out of the tracheal system, aiding ventilation and gas exchange.
What role do tracheoles play in gas exchange?
Tracheoles are the smallest branches of the tracheal system and are directly involved in the diffusion of gases into and out of tissues.
How does water move in the tracheoles during exercise?
During exercise, lactic acid accumulates in tissues, lowering water potential and causing water to move out of tracheoles, increasing gas exchange efficiency.
What is the structure of mammalian lungs?
Mammals have lungs with a large surface area made up of alveoli (small air sacs) that are surrounded by a dense network of capillaries for efficient gas exchange.
What is the role of surfactant in the lungs?
Surfactant reduces surface tension in the alveoli, preventing their collapse and making it easier for the lungs to expand during inhalation.
How does ventilation occur in mammals?
Mammals use a diaphragm and rib muscles to create pressure changes in the thoracic cavity, drawing air into the lungs and expelling it through exhalation.
What is the role of alveolar-capillary diffusion?
Oxygen diffuses from the alveoli (high concentration) into the blood in the capillaries (low concentration), while carbon dioxide diffuses the opposite way.
Why are mammalian lungs so efficient at gas exchange?
They have a large surface area, a thin epithelial layer, a rich blood supply, and a constant ventilation mechanism, maintaining a steep concentration gradient for gases.
How do fish exchange gases?
Fish use gills to extract oxygen from water. The gills are made up of thin filaments and lamellae that maximize surface area for diffusion.
What is countercurrent flow in fish?
Countercurrent flow refers to the opposite direction of blood and water flow across the gills, maintaining a concentration gradient for efficient oxygen uptake.
How does water flow over fish gills?
Fish open their mouths to draw water in, then force it over their gills by closing their mouths and expanding their pharyngeal cavity, allowing gas exchange to occur.
What is the function of gill filaments?
Gill filaments are thin structures in fish that provide a large surface area for oxygen diffusion from water to blood.
Why is countercurrent flow more efficient than parallel flow?
Countercurrent flow maintains a gradient where the oxygen concentration in water is always higher than in the blood, leading to maximum oxygen uptake.
How do birds exchange gases?
Birds have a highly efficient respiratory system with air sacs and unidirectional airflow, allowing for continuous oxygen supply.
What is the function of air sacs in birds?
Air sacs allow birds to store and move air through the lungs during both inhalation and exhalation, maintaining constant airflow and maximizing oxygen extraction.
How does unidirectional airflow benefit birds?
Unidirectional airflow ensures that air in the lungs always contains oxygen, preventing stale air from mixing with fresh air and maintaining a high oxygen concentration.
What is the advantage of bird respiratory efficiency?
The unidirectional airflow and air sacs ensure that oxygen is extracted more efficiently, which is vital for high-energy flight.
