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Vocabulary words
aerobic respiration
air sacs
alveolus
asthma
breathing
bronchiole
bronchus
cell respiration
gas exchange
diaphragm
epiglottis
gills glottis hemoglobin larynx (voicebox) lung Cancer lungs nasal cavity nose pharynx
pneumonia residual volume respiratory medium
respiratory surface rib muscles spiracle surface tension
tidal volume trachea or windpipe tracheae tuberculosis ventilation vital capacity vocal cords of the larynx
Gas exchange supplies oxygen for cellular respiration and removes CO2 Gas exchange –
uptake of O2 from environment and discharge of CO2
Mitochondria need O2 to produce more ATP, CO2 is the by-product
C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP
Diffusion rate α SA large α 1/d2 thin
Moist so gases are dissolved first
DIFFUSION
Respiratory surfaces and gas exchange
Respiratory surface Size of organism Habitat Metabolic demands
Unicellular organisms Entire surface area
for diffusion
Simple invertebrates Sponges,
cnidarians, flatworms
diffusion
Respiratory surfaces and gas exchange More complex
animals Thin, moist
epithelium Separates medium
from capillaries Entire outer skin
small, long, thin organisms
Specialized respiratory organs that are extensively folded and branched
Gills in aquatic animals
Outfoldings of the body surface suspended in water
Sea stars Segmented worms
or polychaetes Molluscs and
crustaceans Fishes Young amphibians Total surface area is
greater than the rest of the body
Just keep swimmin
g swimmin
g swimmin
g!
Water as a respiratory medium Surfaces are kept moist O2 concentrations in
water are low Ventilation – increasing
flow of respiratory medium over the surface
Countercurrent exchange – process in which two fluids flow in opposite directions, maximizing transfer rates
Why are gills impractical for land animals?
Air as a respiratory medium Air has a higher
concentration of O2 O2 and CO2 diffuse
much faster in the air less ventilation
Difficulty of keeping surface moist
Solution: respiratory infolding inside the body
Tracheal system of insects – network of tubes that bring O2 to every cell
Spiracles
Lungs Heavily vascularized
invaginations of the body surface restricted to one location
Found in spiders, terrestrial snails, vertebrates
Amphibians supplement lung breathing with skin
Turtles supplement lung breathing with moist surfaces in mouth and anus
Mammalian respiration
Extra pictures
Lung ventilation through breathing
Positive pressure breathing in frogs
“Gulping in” air
Negative pressure breathing in reptiles and mammals
Rib muscles and diaphragm change lung volume and pressure
Lung volumes Factors
Sex Height Smoking Physical activity Altitude
Tidal volume Volume of air inhaled
and exhaled with each breath
Vital capacity Maximum volume
inhaled and exhaled during forced breathing
Residual volume Air left in alveoli after
forced exhalation
Avian breathing
Air sacs act as bellows to keep air flowing through the lungs.
Control centers in the brain regulate breathing
Gases diffuse down pressure gradients
concentration and pressure drives the movement of gases into and out of blood