gas exchange Flashcards
(9 cards)
why is gas exchange important?
essential for organisms that rely on oxygen to produce ATP through cellular respiration.
What are the key characteristics of respiratory surfaces?
Aqueous solution: Cells involved in gas exchange must be in contact with water to enable simple diffusion.
Gas exchange is more efficient with large surface area (SA) and a short diffusion distance.
How do earthworms and amphibians perform gas exchange?
cutaneous respiration, gas exchange occurs across their skin, which is highly vascularized with many capillary beds.
describe ventilation and countercurrent exchange
Ventilation (movement of water over gills) helps maintain partial pressure gradients for O₂ and CO₂.
Countercurrent exchange where blood flows in the opposite direction to the water over the gills, maximizing O₂ uptake.
What are the key features of the tracheal system in insects?
The tracheal system consists of a network of air tubes (tracheae) that branch throughout the insect’s body.
Tracheae open to the outside and function without a circulatory system.
What are lungs, and how do they function in terrestrial animals?
Lungs are infoldings of the body surface and are typically subdivided into many pockets.
Gas exchange occurs within alveoli, and the lungs must be connected to the circulatory system for nutrient and oxygen transport.
What is the mammalian respiratory system?
Air enters through the nostrils, where it is filtered, warmed, humidified, and sampled for odors.
Air passes through the nasal cavity, pharynx, larynx, and trachea, which branches into bronchi and further into the lungs.
The bronchi are lined with cilia and mucous to trap contaminants.
Gas exchange occurs in the alveoli, air sacs at the ends of bronchioles.
How does breathing occur in mammals?
Negative pressure breathing: Air is pulled into the lungs due to the diaphragm’s contraction.
breathing regulated in mammals?
Breathing is regulated by involuntary mechanisms
The medulla oblongata in the brainstem is the control center.
Negative feedback mechanisms prevent lungs from overexpanding, using blood pH as an indicator of CO₂ levels.
