Lecture 14: Ventilation and Gas exchange in Animals Flashcards
what is gas exchange?
it is the process by which organisms uptake gasses required for physiological processes and release waste gasses as a byproduct of those processes
what gasses do animal cells uptake and release?
uptake oxygen and release carbon dioxide
what are sources of oxygen and explain properties of both?
air and water.
air: oxygen is plentiful in the air/21% and it is not dense or viscous. it is easy to breathe so does not require much efficiency.
water: oxygen is scarce in water. it is dense and viscous
movement of co2 and o2 moves entirely via?
diffusion
what is the respiratory surface in leaves?
mesophyll parenchyma cells
what is the respiratory surface in humans?
alveoli in the lungs
what should respiratory surfaces have to maximize diffusion efficiency?
- large surface area
- thin and one cell thick
- moist
what does ventilation mean?
ventilation is the flow of respiratory medium over the respiratory surface
respiratory medium: air or water
ventilation and gas exchange occurs in different animals in different ways because?
depending on environment and locomotion
if air is the medium, the fresh o2 in the air can reach the respiratory surface in multiple ways including?
1: diffusion: no pressure involved, relying on concentration gradient. Ex: insects
2: positive pressure: o2 is pushed via buildup of pressure Ex: amphibians and birds
3: negative pressure: o2 is pulled via drop in pressure Ex: mammals
Porifera gas exchange?
environment: aquatic
respiratory medium: water
respiratory surface: body wall
ventilation: flagella in the collar cells pull water in through pores in the body
locomotion: sessile
Cnidaria gas exchange?
environment: aquatic
respiratory medium: water
respiratory surface: body wall and lining of gastrovascular cavity
ventilation: water circulates through the gastrovascular cavity
locomotion: sessile, weak swimmers
Platyhelminthes gas exchange?
environment: aquatic or parasitic
respiratory medium: water or host fluids
respiratory surface: body wall and lining of gastrovascular cavity
ventilation: simple diffusion across outer body surface and gastrovascular cavity
locomotion: sessile or slow swimmers
insects gas exchange?
environment: terrestrial but some aquatic
respiratory medium: mostly air
respiratory surface: tracheal system, air sacs, and some aquatic insects have gills
ventilation: tracheal system: spiracles where the air enters the body and the trachea branch into thinner tracheoles which deliver gasses to each cell.
SMALL INSECTS: diffusion
LARGE INSECTS: use muscles to contract and expand body to pump air
locomotion: crawling, jumping, flying, fast locomotion requires rapid gas exchange to support high metabolic rate
where does gas exchange occur in animals?
specialized structures: gills or lungs