Zusammenfassung der Ressource
Gaseous Exchange
- Plants
- leaves
- thin, flat and large Surface Area
- shorter diffusion path
- lots of Stomata
- lots of air spaces in Spongy Mesophyll
- Diffusion
- Single-Celled Organisms
- large Surface Area:Volume ratio
- Diffusion is sufficient due to size
- thin Cell Surface Membrane
- short diffusion pathway
- Insects
- Trachae
- give large Surface Area
- lots of Spiracles
- short diffusion pathway
- active insects have muscles to
Ventilate Trachae
- maintains high Concentration Gradient
- Diffusion in gas phase - faster
- Fish
- Gill Filaments and Lamellae
provide massive Surface Area
- Lamellae
- lots of capillaries
- thin surface layer
- faster Diffusion
- Counter-Current system
- maintains high Concentration Gradient
- Humans
Anlagen:
- Ventilation
- maintains high
Concentration Gradient
- Inhalation
- Ribs UP Muscles DOWN
Volume UP Pressure DOWN
- Muscles = Diaphragm and External
Intercostals contract
- Exhalation
- Ribs DOWN Muscles UP
Volume DOWN Pressure UP
- Muscles = Diaphragm and External
Intercostals relax
- when at rest, Tidal and Passive
- when exercising, Internal Intercostals contract too,
pulling ribs down further and increasing volume in
thorax more; muscles in abdomen wall contract, pushing
diaphragm up further, increasing volume exhaled
- Pulmonary Ventilation = Tidal Volume x Ventilation Rate
- PULMONARY VENTILATION:
total vol of air moved into lungs
during one minute
- TIDAL VOLUME: vol of gas
inspired/expired during each
unforced ventilation cycle
- VENTILATION RATE: number
of breaths per minute
- lots of Alveoli
- large surface area
- surrounded by Capillaries
- maintain conc grad
- short partially-permeable
diffusion pathway
- RBCs compressed
against capillary wall
- moist surface in which oxygen
dissolves to help diffusion