DIFFUSION IS THE PASSIVE NET MOVEMENT OF MOLECULES DOWN A CONCENTRATION GRADIENT (HIGH TO LOW) UNTIL EVENLY DISTRIBUTED
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HOW AND WHY ARE EXCHANGE SURFACES ADAPTED FOR EFFICIENT DIFFUSION?
LARGE SA:VOL RATIO- LARGER THE SA:VOLRATIO THE QUICKER THE DIFFUSION. USUALLY 1 ENDOTHELIAL CELL LAYER THICK- GIVES A SHORT DIFFUSION PATHWAY. ORGANISM BREATHES IN AND OUT CONSTANTLY- KEEPS CONCENTRATION GRADIENT STEEP
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HOW DOES SA:VOL RATIO AFFECT DIFFUSION?
LARGE OBJECTS HAVE SMALL SA:VOL RATIO- SMALL=SLOW RATE OF DIFFUSION. SMALL OBJECTS HAVE LARGE SA:VOL RATIOS- LARGE= FAST RATE OF DIFFUSION
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HOW DOES TEMPERATURE AFFECT DIFFUSION?
HIGHER TEMP- MOLECULES HAVE MORE KINETIC ENERGY- MOVE FASTER- CAUSES FASTER DIFFUSION
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WHAT IS THE EXCHANGE SURFACE CALLED IN THE LUNGS?
ALVEOLAR EPITHELIUM
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HOW DOES GAS EXCHANGE OCCUR IN THE LUNGS?
OXYGEN DIFFUSES OUT OF ALVEOLI ACROSS ALVEOLAR EPITHELIUM AND THE CAPILARY ENDOTHELIUM, AND INTO THE BLOOD. CARBON DIOXIDE DIFFUSES INTO ALVEOLI FROM THE BLOODAND IS BREATHED OUT
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HOW IS A HIGH RATE OF DIFFUSION ACHIEVED IN THE LUNGS?
LOTS OF ALVEOLI- LARGE SURFACE AREA. ALVEOLAR EPITHELIUM AND CAPPILARY ENDOTHELIUM ARE ONE CELL LAYER THICK- SHORT DIFFUSION PATHWAY. GOOD BLOOD SUPPLY- CONSTANTLY TAKE AWAY OXYGEN AND BRING MORE CARBON DIOXIDE- MAINTAINING CONCENTRATION GRADIENT
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WHAT IS THE PURPOSE OF BREATHING IN AND OUT ALL THE TIME?
KEEPS CONCENTRATION GRADIENT HIGH
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WHAT IS FICKS LAW?
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Other cards in this set
Card 2
Front
HOW AND WHY ARE EXCHANGE SURFACES ADAPTED FOR EFFICIENT DIFFUSION?
Back
LARGE SA:VOL RATIO- LARGER THE SA:VOLRATIO THE QUICKER THE DIFFUSION. USUALLY 1 ENDOTHELIAL CELL LAYER THICK- GIVES A SHORT DIFFUSION PATHWAY. ORGANISM BREATHES IN AND OUT CONSTANTLY- KEEPS CONCENTRATION GRADIENT STEEP
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