Gas Exchange Flashcards
What are the features of an efficient gas exchange system?
-Large surface area
-Thin layers to speed up diffusion
-Rich blood supply to maintain concentration gradients
-Moisture surfaces to speed up diffusion
-Permeable surfaces to allow gases through
What are the adaptations of the alveoli?
-Cell wall is one cell thick
-Elastic tissue holds the capillary to the alveoli which helps force air out
-Lung
What is a mass transport system?
An arrangement of structures by which substances are transported in the flow of a fluid with a mechanism for moving it around the body
What are spiracles?
The openings along the side of the thorax and abdomen of an insect that are the entry and exit of respiratory gases
What are tracheae?
The largest tubes of the insect respiratory system which carry air directly into the body for gas exchange with the cells
What are tracheoles?
Small tubes that are the site of gaseous exchange in insects
What are gills?
The organs of gas exchange in a fish
What is the operculum?
The bony protective flap that covers the gills of bony fish
What is a countercurrent exchange system?
A system in which two fluid components flow in opposite directions and some properties are exchanged between the two fluids
How is gas exchanged in fish?
-Water flows in through the mouth
-Water flows over the gills
-Water flows out through the operculum
-Fish without an operculum must continuously move
How are fish adapted for efficient gas exchange?
-Gills have a good blood supply
-They have a countercurrent exchange system
-The countercurrent exchange system maintains the concentration gradient allowing the diffusion of oxygen into the blood
-Gills are made of overlapping gill filaments (lamelle) which have a large surface area and a good blood supply
How is gas exchanged in insects?
-Air moves along the tracheae and tracheoles by diffusion
-The tracheae and tracheoles provide a large surface area
-The spiracles open and close to control the rate of gas exchange
What ways can insects exchange gas?
-Mechanical pumping = insect moves its thorax in a muscular pumping motion which draws air in and out of the spiracles
-Collapsible tracheae = acts as air reservoirs and the movement of the thorax can inflate or deflate them
What are lenticles?
A porous tissue with huge intercellular spaces
-it allows air to reach the remaining parts of the root system
What are spongy mesophyll cells?
Cells inside the leaf where gas exchange takes place
-they have a high concentration of oxygen
What are stomota?
Specialised pores found mainly in the epidermis on the underside of the leaf where gases diffuse into and out of the cell
What are guard cells?
Cells that open and close the stomata pores which control the rate of gas exchange
What is palisade mesophyll?
Packs many cells together meaning there is more chlorophyll so more photosynthesis can occur
What is a xerophytic plant?
A plant adapted to survive in environments with little water
-they have structures which make gas exchange more efficient and limit water loss
What are the adaptations of a xerophytic plant?
-Curled leaves and have hairs on their leaves to trap moisture to increase humidity and lower the rate of evaporation
-Thicker cuticle to trap the evaporating water
-Longer network of roots to access more water
-Sunken stomata to trap moisture to increase the humidity and lower the rate of evaporation
Why are there gaps within the mesophyll layer?
Maintains a concentration gradient which allows gases to diffuse
What is a guard cell?
Found on the underside of a leaf and control the opening and closing of the stomata
-open the stomata during the day
-close the stomata during the night
