Adaptations for Gas Exchange
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- Created by: Ellen122
- Created on: 20-03-21 14:50
Gas Exchange
All organisms need to exchange gases with their environment - air or water
Volume determines their oxygen requirement
Volume determines their oxygen requirement
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High Rates of Diffusion
Large surface area relative to the volume of the organism
Thin to provide a short diffusion distance
Permeable
Moist to dissolve the gasses before diffusion
Ventilated to maintain a concentration gradient
Thin to provide a short diffusion distance
Permeable
Moist to dissolve the gasses before diffusion
Ventilated to maintain a concentration gradient
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Single Celled Organisms
Amoeba
Sufficiently large surface area:volume ration to be able to use its cell membrane as a respiratory surface
Sufficiently large surface area:volume ration to be able to use its cell membrane as a respiratory surface
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Multicellular Organisms
Larger their surface area: volume ration decreases
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Flatworms
Evolved a flattened shape which increases their surface area:volume ratio and provides a short diffusion distance to all body parts
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Earthworms
Cylindrical shape
Increases their surface area: volume ratio
Able to use their moist skin as an exchange surface
Prone to dessication
Possess a closed circulatory system with a pigment for the transport of oxygen to all body parts
Increases their surface area: volume ratio
Able to use their moist skin as an exchange surface
Prone to dessication
Possess a closed circulatory system with a pigment for the transport of oxygen to all body parts
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Larger and More Advanced Multicellular Organisms
Require specialised exchange surface to provide sufficient oxygen for their higher metabolic rate
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Gas Exchange in Insects
Segements contain paired holes called spiracles which run either side of their bodies
Spiracles are the openings to a series of branched chitin lined tubes called trachae which divide further into tracheoles
Gas exchange occurs there without the involveme
Spiracles are the openings to a series of branched chitin lined tubes called trachae which divide further into tracheoles
Gas exchange occurs there without the involveme
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Gas Exchange in Water
Most aquatic and marin organisms use gills to exchange gases
Water is more dense than air and contains less oxygen
The gills are folded to provide a large surface area
Dense water prevents the folds from collapsing on top of each other and reducing the su
Water is more dense than air and contains less oxygen
The gills are folded to provide a large surface area
Dense water prevents the folds from collapsing on top of each other and reducing the su
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Cartilaginous Fish
Sharks and rays have 5 gill slits on either side of their heads
Water is taken into the mouth and forced past the gills and out of the slits when the floor of the mouth is raised
Water passes the gill capillaries in the same direction as the blood flow
Pa
Water is taken into the mouth and forced past the gills and out of the slits when the floor of the mouth is raised
Water passes the gill capillaries in the same direction as the blood flow
Pa
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Bony Fish
4 pairs of gills in their pharynx
Gill is supported by a gill arch
Along the gill there are many plates called gill lamellae
Gill plates on the gill lamellae are the gas exchange surface
Blood in the capillaries of the gill plates flows in the opposite di
Gill is supported by a gill arch
Along the gill there are many plates called gill lamellae
Gill plates on the gill lamellae are the gas exchange surface
Blood in the capillaries of the gill plates flows in the opposite di
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Bony Fish Ventilation
Closing their mouths
Raise the floor of the buccal cavity to force the water past their gills and out of the operculum
Fresh water is brought into the mouth by opening it and lowering the floor of the buccal cavity to lower the pressure inside the mouth
Raise the floor of the buccal cavity to force the water past their gills and out of the operculum
Fresh water is brought into the mouth by opening it and lowering the floor of the buccal cavity to lower the pressure inside the mouth
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Amphibians
Larvae have gills
Metamorphose into adults their moist skin and simple lungs take over as the organs of gaseous exchange
Lack ribs ventilating their simple balloon lungs
Metamorphose into adults their moist skin and simple lungs take over as the organs of gaseous exchange
Lack ribs ventilating their simple balloon lungs
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Reptiles
Better adapted to life on land than amphibians
Have ribs projecting from their vertebrae
Provide support and protection for their internal organs
Help to ventilate their lungs
Reptilian lungs have in-growths of tissues that increase their surface area
Have ribs projecting from their vertebrae
Provide support and protection for their internal organs
Help to ventilate their lungs
Reptilian lungs have in-growths of tissues that increase their surface area
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Humans
Lungs are enclosed in an airtight thorac
Ventilated by the movement of the ribs and the diaphragm
Friction with the ribs is reduced by pleural fluid secretted by the pleural membranes
Increasing the volume of the thorax lowers the pressure and air is draw
Ventilated by the movement of the ribs and the diaphragm
Friction with the ribs is reduced by pleural fluid secretted by the pleural membranes
Increasing the volume of the thorax lowers the pressure and air is draw
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Inspiration
High concentration of oxygen (~20%) and a low concentration of carbon dioxide (~0.04%)
Deoxygenated blood arrives from the pulmonary artery with a low concentration of oxygen and a high concentration of carbon dioxide
Allows oxygen to diffuse into the blo
Deoxygenated blood arrives from the pulmonary artery with a low concentration of oxygen and a high concentration of carbon dioxide
Allows oxygen to diffuse into the blo
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Expiration
Gradually decrease the concentration gradient between the blood and the air in the alveolus
Reduces the volume in the lungs and increases the pressure
Forcing stale air out of the alveoli
Replacing it with fresh air during inspiration
Reduces the volume in the lungs and increases the pressure
Forcing stale air out of the alveoli
Replacing it with fresh air during inspiration
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Movement of Oxygenated Blood
Oxygenated blood in the capillaries next to the alveoli between the alveoli betweeen the pulmonary artery and the pulmonary vein helps to maintain the concentration gradient between the air in the alveoli and the blood in the capillaries
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Evolution of Mammalian Lungs
Evolved to exchange gases without excessive water loss
Lungs are ventilated to maintain a concentration gradient between the air in the lungs and the blood in the capillaries surrounding the alveoli
Lungs are ventilated to maintain a concentration gradient between the air in the lungs and the blood in the capillaries surrounding the alveoli
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Adaptations of the Alveoli
Thin walls - only one cell thick
Permeable allowing rapid diffusion
Moist lining to dissolve the oxygen so that it can be absorbed into the bloodstream
Rich blood supply to carry oxygenated blood around the boyd
Maintaining concentration gradient between
Permeable allowing rapid diffusion
Moist lining to dissolve the oxygen so that it can be absorbed into the bloodstream
Rich blood supply to carry oxygenated blood around the boyd
Maintaining concentration gradient between
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Spirometer
It monitors breathing
Measures the volumes of air that are breathed during normal breathing - tidal volume
Forced breathing - vital capcity
Even after forced exhalation there is still some air left in the trachea, bronchi, bronchioles and alveoli - residu
Measures the volumes of air that are breathed during normal breathing - tidal volume
Forced breathing - vital capcity
Even after forced exhalation there is still some air left in the trachea, bronchi, bronchioles and alveoli - residu
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Birds
Greatest demand of all vertebrates to provide the energy for flight
Lungs are similar in structure to mammalian lungs, but have a system of air sacs connected to them
Air sacs act like bellows drawing in the air that remains in the lungs from previous ven
Lungs are similar in structure to mammalian lungs, but have a system of air sacs connected to them
Air sacs act like bellows drawing in the air that remains in the lungs from previous ven
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Plants
Leaf is the organ of gas exchange in plants
Moist spongy mesophyll provides a large surface area
Stomata permit entry and exit of gases between the air spaces in the spongy mesophyll and the air outside the leaf
Moist spongy mesophyll provides a large surface area
Stomata permit entry and exit of gases between the air spaces in the spongy mesophyll and the air outside the leaf
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Adaptations of the Leaf for Photosynthesis
A large surface area
Leaves move to remain perpendicular to sunlight
Transparent cuticle and epidermis
Palisade cells arranged vertically and packed with chloroplasts
Chloroplasts can move within the mesophyll cells to maximise absorbance of light
Interce
Leaves move to remain perpendicular to sunlight
Transparent cuticle and epidermis
Palisade cells arranged vertically and packed with chloroplasts
Chloroplasts can move within the mesophyll cells to maximise absorbance of light
Interce
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Stomatal Opening Mechanism
The guard cells surrounding the stomata have thickened inner walls so that when the guard cells become turgied they change shpae to open the pore
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Stomata During Daylight
Potassium ions are pumped into the guard cells, stored starch is also converted to malate.
Lower water potential of the guard cells and water enters causing them to swell and open the pore
Lower water potential of the guard cells and water enters causing them to swell and open the pore
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Water Stress
During periods of water stress the plants will close their stomata to reduce water loss
Xerophytes have other adaptations to reduce water loss
Xerophytes have other adaptations to reduce water loss
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Ventilation of Lungs Inspiration
The diaphragm contracts and flattens
The external intercostal muscles contract and lift the ribs up and out
Both increase the volume in the thorax
The pleural fluid increase the volume of the lungs
The pressure inside the lungs is lowered
Air enters down
The external intercostal muscles contract and lift the ribs up and out
Both increase the volume in the thorax
The pleural fluid increase the volume of the lungs
The pressure inside the lungs is lowered
Air enters down
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Venilation of Lungs Expiration
The external intercostal muscles relax and gravity pulls ribs down and in
Elastic recoil of the lungs
Elastic recoil of the guts pushes the diaphragm back up
Both decrease the volume in the thorax
The pleural fluid decreases the volume of the lungs
The pr
Elastic recoil of the lungs
Elastic recoil of the guts pushes the diaphragm back up
Both decrease the volume in the thorax
The pleural fluid decreases the volume of the lungs
The pr
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Other cards in this set
Card 2
Front
High Rates of Diffusion
Back
Large surface area relative to the volume of the organism
Thin to provide a short diffusion distance
Permeable
Moist to dissolve the gasses before diffusion
Ventilated to maintain a concentration gradient
Thin to provide a short diffusion distance
Permeable
Moist to dissolve the gasses before diffusion
Ventilated to maintain a concentration gradient
Card 3
Front
Single Celled Organisms
Back
Card 4
Front
Multicellular Organisms
Back
Card 5
Front
Flatworms
Back
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