Gas Exchange Flashcards
What is this equation?
M= [D x A( Cext - Cin)]/L
What are the units?
Ficks M = mass of gas D = diffusion coefficient A = area Cext - Cin = concentration gradient L = thickness
Name the 4 kinds of gas exchange
- Skin/cutaneous
- Gills
- Trachae
- Lungs
Name 3 organisms that use cutaneous respiration
Sponges
Anemones
Platyhelminthes
What is diffusion dependent on?
Total surface area of respiratory structure
Permeability of the surface
Gradient of gas
Describe cutaneous respiration
direct gas exchange across the body surface
requires thin, moist, highly vascularized skin to be effective
Route of water flow in sponges
- dermal pores
- incurrent canals
- flagellated chambers lined with choanocytes
- spongocoel (atrium)
- osculum
Name 2 organisms that use cutaneous respiration
Sponges (sycon)
Platyheminthes (giardia)
Describe gills
evaginations of the body surface, which may open directly to the environment or may be enclosed in a cavity
thin-walled processes well supplied with blood or other bodily fluid that allow diffusion
highly folded
large surface area relative to their mass
need flow of water
How do gills flow water?
- move gill through water
2. move water over gills - ciliary flow or pump-like action
why do gills need constant water flow?
need water so that oxygen does not become depleted, especially in the boundary layer
Name 4 organisms that use gills
polychaeta (nereis)
feather dustres
squid
crayfish/crabs
Polycheate gas exchange
use their body surface and additional specialized gills
segmental flaps or branchial tufts
Nereis gas exchange
parapodium
Feather duster gas exhange
brachial crowns
Squid gas exchange
ventilate a protected chamber lined with feathery gills that contain capillaries
Crayfish/crab gas exchange
gills enclosed in protective chambers and ventilation is provided by specialized appendages
faster crabs = more gill area
terrestrial crabs = reduction of gills
increase in ventilation = decrease in partial pressure of oxygen
How to lungs work?
invaginations of the body surface that air moves in and out of the body through branched tubular pathways
air reaches membrane where gas exchange occurs then it’s circulated through the body
typically in terrestrial environments
Spider gas exchange structure
book lungs
insect, centipedes and millipedes gas exchange structure
tracheae
Land snail and slug gas exchange structure
lung which open via pneumostome
Describe pneumostome
small opening in the mantle cavity on the right-hand side of the organism
allows air to enter the highly vascularized lung
Sea cucumber gas exchange structure
Respiratory tree
Describe respiratory tree
branched hollow outpouchings of the cloaca (hindgut)
water pumped in and out by the action of cloaca
Sea cucumber digestive system
mouth pharynx calcareous ring esophagus stomach intestine cloaca cloacal dilator muscles anus
Sea cucumber respiratory system
2 respiratory trees
inhale= close intestinal sphincter, relax anal sphincter, contract cloacal dilator muscles
inspires water into cloaca, sphincters close and circular muscles in the clocal wall are contracted forcing water into respiratory tree
gas exchange between coelomic fluid and seawater in walls of tree
exhale= contraction of muscles in the walls of tree with intestinal sphincter closed and anal sphincter open
Describe book lungs
blind inpocketings with highly folded inner linings across which gasses diffuse between hemolymph and air
Describe tracheae
invaginations of cuticular exoskeleton
highly branched
air-filled tubular passages connect the body surface with all internal structures
Describe tracheoles
smallest tubes in tracheae
directly penetrate cells and serve as cites for diffusion for water oxygen and carbon dioxide
Describe spiracles
external structures on exoskeleton of insects and most arthropods
open and close to prevent water loss during respiration
