Breathing Water

Question 1

how much o2 is in air compared to water

Answer 1

209ml/liter to 6.8ml/liter

Question 2

what affects oxygen content in water

Answer 2

• temperature (O2 decrease as it increases)
• salinity (O2 decrease, as it increases)

Question 3

the 3 things needed to breathe water

Answer 3

1. gills
2. flowing water
3. flowing blood

Question 4

how does water enter and exit the gills?

Answer 4

in sharks
- through mouth and spiracle, through gills and out through gill slits
in fish
- through mouth, over gills and out the operculum

Question 5

what are the 2 types of ventilation

Answer 5

Ram Ventilation
- sharks and big fish swim with mouth open to get constant rush of water inside
Buccal Pump
- Suction: buccal cavity expands allowing more volume which lower pressures and water comes rushing in and can’t flow backwards
-Force: mouth closes and and forces water over the gills and out the slit operculum

Question 6

the circuit of blood

Answer 6

heart- gills- body back to heart (single circuit) so blood is mixed

Question 7

how are the gills organized?

Answer 7

septums between chambers
septum with chambers on both sides: interbranchial septum
septum with one chamber: a simple septum

Question 8

structure of gills

Answer 8

they have parallel filament to maximize surface area for gas exchange

Question 9

why are gills efficient

Answer 9

large surface area and short diffusion rate

Question 10

what direction does blood come compared to the water

Answer 10

counter current exchange: they come in the opposite direction so that the concentration gradient for exchange is favourable wherever in the path