Gas Exchange Flashcards
Name adaptations of respiratory surfaces
Thin
Large surface area
Moist
Permeable
Gas exchange in amoeba
Unicellular organism, membrane is respiratory surface. Very short diffusion distance across membrane.
Gas exchange in earthworms
Land organism with skin as respiratory surface, which is kept moist by secreted mucus. Blood capillaries under the skin take away the oxygenated blood
Gas exchange in flatworms
Flatworms have a large surface area to volume ratio and are aquatic animals so they absorb oxygen through their moist skin
What is the respiratory surface of insects
Where the trachiole meets the muscle fibre
What is the respiratory pathway of an insect
Spiricles, trachea, tracheoles, muscle fibre
Gas exchange in amphibians
Frogs have moist, permeable skin which they use as their respiratory surface, and use their lung when active. They have lots of capillaries under their skin and around their lung
Gas exchange in reptiles
Lungs are protected by ribcage and have folded internal respiratory surface
Gas exchange in birds
Air sacs function as bellows, filling the lungs. This process is aided by the flight muscles and birds can fly for a long time because some air sacs extend into their bones
Gas exchange in cartilaginous fish
Fish have gills which have a large surface area. Oxygen is obtained by diffusion when water flows across the gills. The water flows over the gills in the same direction as the blood, causing a decreasing concentration gradient, decreasing diffusion down the length of the lamella
Gas exchnage in bony fish
The gills are covered by the operculum which causes pressure changes in the gills and mouth. The operculum acts as a valve and pump. The water flows over the gills in the opposite direction to the blood flow causing counter-current flow and a maintained concentration gradient along the length of the lamella
Give the process of human ventilation (inhalation)
External intercostal muscles contract ribs pull upwards and outwards diaphragm contracts and flattens thorax volume increases pressure decreases air drawn in
Give the process of human ventilation (exhalation)
External intercostal muscles contract ribs move downwards and inwards diaphrgm relaxes and domes upwards thorax volume decreases pressure increases air forced out of lungs
What stops the alveoli collapsing during exhalation
surfactant
What is the function of pleural fluid
forces the lungs to expand and acts as a cushion between the lungs and ribcage
