Respiration
Rachel Muheim
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
What is respiration?
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Cellular respiration in
mitochondria
ATP yield from the complete oxidation of
glucose:
C6H12O6 + 38 ADP + 36 P + 6 O2
↓
6 CO2 + 38 ATP + 6 H20
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Transport of gases
Transport of oxygen and carbon dioxide over distances of
< 1 mm: via diffusion
> 1 mm: within a medium (hemolymph, blood)
In animals where the distance between any point of the body and the body
surface is >1 mm, several processes are usually involved in respiration:
• Ventilation: Breathing movements
• Diffusion of gases across a respiratory epithelium
• Bulk transport of gases by blood or hemolymph
• Diffusion of the gases to the tissue cells
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration in air and water
Water
Air
Concentration of O2
Density
Viscosity
Diffusion of O2 and CO2
low
high (x 800)
high (x 50)
slow
high
low
low
fast (x 10000)
Energy cost to extract oxygen
20 %
1-2 %
Air contains ~30 times more oxygen per liter and ~23 000 times more oxygen
per kg than water!
→ Respiration of air is much cheaper, and a smaller volume and mass needs
to be transported per unit oxygen!
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiratory organs
Exchange of oxygen / carbon dioxide through:
• Skin or integument:
• humans: 1%
• snakes: 10%
• amphibians: up to 100%
• eels: up to 60%
• endoparasites: 100%
• earthworm: 100%
WATER
• Epithelium of intestines
WATER
• Tracheae: air filled tubes AIR
• Gills: evaginations of body surface
• outer gills: outside of body
WATER
• inner gills: inside of body
• Lungs: invaginations of body surface AIR
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration
via diffusion
Protozoans, sponges,
cnidarians, many worms
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration via diffusion: skin and epithelia
• Flatworms have a thin body to achieve
adequate gas exchange
• Larger animals can use cutaneous respiration
as supplement to gills or lungs
• Some frogs and salamanders are entirely
lungless
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Gas exchange through tracheae
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Adaptations to tracheal
system in water-living insects
• Dragonfly larvae: use hindgut as airfilled reservoir
• Some water bugs: carry a layer of air
at parts of their bodies covered with
hydrophobic hairs (plastron)
• Other water bugs store
oxygen in hemoglobinfilled cells
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Tracheal gills in water-living insects and insect larvae
• Mayfly larvae: tracheae extend into
appendages of the abdomen,
“tracheal gills”
• Mosquito larvae: reduced number
of spiracles positioned at the hind
end of the body and surrounded by
hydrophobic hairs
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration in water with gills
Gills = extensions of the epithelium into the surrounding oxygen-rich medium
Structure:
– simple extensions (tube feet in echinoderms)
– filament gills (tadpoles and aquatic arthropods)
– lamellar gills (molluscs and fishes)
Position:
– external gills that are common in tadpoles, marine invertebrates
including echinoderms, annelids, fan-worms and crustaceans
– internal gills that are found in larger crustaceans, fish, aquatic
gastropods and bivalves
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration through simple extensions tube feet of echinoderms
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration with
external filament gills
in polychaetes
Havsborstmaskar
Errant polychaete
Amphitrite
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration in water with external filament
gills in nudibranchs and gastropods
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration in water with
external filament gills in amphibians
Barred Tiger Salamander, Ambystoma
mavortium mavortium
Mexican Axolotl, Ambystoma mexicanum
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Evolution of mollusc gills
from ctenidia
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration in water with internal
lamellar gills in muscles
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Book gills in Horseshoe Crabs
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration in water with internal
lamellar gills in crustaceans
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Land living crustaceans with internal gills
Coconut crab
Wood louse
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Fish gills
Bony fish
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Elasmobranch fish
Internal lamellar
gills of fishes
Countercurrent gas exchange maximizes exchange of gases:
Oxygen concentration
water
low
high
blood
Reverse principle for carbon dioxide...
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration in fishes outside of the water
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration with lungs in air
Two types of lungs:
• Diffusion lungs: gas transport
takes place via diffusion
• Ventilation lungs: air is moved in
and out of the lung via an active
pressure or suction pump
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Respiration with diffusion lung
in land snails and slugs
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Book lung of spiders and scorpions
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Water lung in sea cucumbers
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Evolution of vertebrate lungs
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Rudimentary lungs of lungfish
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Differentiation of vertebrate lungs
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Buccal ventilation in amphibians
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Efficient lungs with
air sacs in birds
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Structure and function of the mammalian
respiratory system
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi
Site of gas exchange: Alveoli
Lund University / Faculty of Science / Department of Biology / BIO B02 – Zoologi