Chapter 42.5 Flashcards
Gas exchange
supplies O2 for cellular respiration
supplies O2 for cellular respiration
gas exchange
What is partial pressure
the pressure exerted by a particular gas in a mixture of gases
What do partial pressures also apply to?
gases dissolved in liquids such as water
how do gases undergo net diffusion
from a region of higher partial pressure to a region of lower partial pressure
What can animals use as their respiratory medium
air or water
respiratory medium
O2 source
The difference between obtaining O2 from water or from air
Obtaining O2 from water requires greater efficiency than air breathing
What do animals require for the exchange of gases between their cells and the respiratory medium (air/water)
large, moist respiratory surfaces
How does gas exchage across respiratory surfaces take place
by diffusion
Respiratory surfaces vary by animal and can include…
skin, gills, tracheae, and lungs
What are gills
outfoldings of the body that create a large surface area for gas exchange
outfoldings of teh body that create a large surface area for gas exchange
gills
what does ventilation do
moves the respiratory medium over the respiratory surface
moves the respiratory medium over the respiratory surface
ventilation
What do aquatic animals do for ventilation
move through water or move water over their gills
What do fish gills use
a countercurrent exchange system
a countercurrent exchange system
blood flows in the opposite direction to water passing over the gills; blood is always less saturated with O2 than the water it meets
In fish gills, what percent of the O2 dissolved in the water is removed as water passes over the respiratory surface
more than 80%
What does the tracheal system of insects consist of
a network of branching tubes throughout the body
what do tracheal tubes supply directly to the body cells
O2
the respiratory and circulatory systems are…
separate
What must larger insects do to meet O2 demands?
ventilate their tracheal system
what are lungs
an infolding of the body surface