Respiratory SystemFunction??????
Lung
Exchangeof gaseswithbodycells
Cell
Capillary
Mitochondria
Breathing
Circulatorysystem
Transportof gases bythe circulatorysystem
CO2
CO2
O2
O21
2
3
Cut
CO2
O2
Cross sectionof respiratorysurface (theouter skin)
Capillaries
• Specialized organs used for gas exchange – Gills in fish and amphibians– Tracheal systems in arthropods– Lungs in tetrapods that live on land
– Amphibians– Reptiles– Birds– Mammals
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• Gills– Increase the surface area for gas exchange
– Oxygen absorbed– Carbon dioxide released
- gas exchange is enhanced by– Ventilation of the gills (moving water past the
gills)– Countercurrent flow of water and blood
Gillarch
Directionof waterflow
Operculum(gill cover)
Gillarch
Bloodvessels
Oxygen-richblood
Oxygen-poorblood
Lamella
Gillfilaments
Water flowbetweenlamellae
Blood flowthroughcapillariesin lamella
Countercurrent exchange
Blood flow insimplified capillary,
showing % O2
Diffusionof O2 fromwater toblood
Water flow, showing % O2
100 70 40 15
5306080
Gillarch
Directionof waterflow
Operculum(gill cover)
Gillarch
Bloodvessels
Oxygen-richblood
Oxygen-poorblood
Lamella
Gillfilaments
Water flowbetweenlamellae
Blood flowthroughcapillariesin lamella
Countercurrent exchange
Blood flow insimplified capillary,
showing % O2
Diffusionof O2 fromwater toblood
Water flow, showing % O2
100 70 40 15
5306080
Gillarch
Directionof waterflow
Operculum(gill cover)
Gillarch
Bloodvessels
Gillfilaments
Gillarch
Bloodvessels
Oxygen-richblood
Oxygen-poorblood
Lamella
Gillfilaments
Water flowbetweenlamellae
Blood flowthroughcapillaries inlamella
Countercurrent exchange
Blood flow insimplified capillary,
showing % O2
Diffusionof O2 fromwater toblood
Water flow, showing % O2
100 70 40 15
5306080
Human Respiratory System
• Trachea– Cilia
• Bronchi• Cartilage• Alveoli• Capillaries• Nasal cavity• larynx
1
5
4
32
8
7
6
9
Alveoli
CO2 O2
CO2-rich,O2-poorblood
O2-rich,CO2-poorblood
Exhaled air Inhaled air
Air spaces
Alveolarcapillaries
Tissuecapillaries
Tissue cellsthroughoutbody
Heart
CO2 O2
CO2 O 2
O2CO 2
Exchange of gases in the alveoli and the tissue cells
Artery from the heart
Vein going to heart
bronchiole
alveoli
capillary
air space
Lung
Diaphragm contracts(moves down)
Diaphragm
Inhalation
Airinhaled
Rib cageexpands asrib musclescontract Volume in thoracic cavity
goes up
Pressure goes down
Low pressure inside, higher outside
air rushes in
Diaphragm relaxes(moves up)
Airexhaled
Rib cage getssmaller asrib musclesrelax
Exhalation
Volume in thoracic cavity goes down
Pressure goes up
higher pressure inside, lower outside
air rushes out
Fig. 22-11
How are the gases carried in the blood?
Oxygen? Carbon dioxide?Most is converted into bicarbonate ions and transported in the blood plasma
CO2 + H2O H2CO3 H+ + HCO3-