7.4 fish ventilation

Question 1

two types of fish

Answer 1

• Cartilaginous fish
• Bony fish

Question 2

Ventilation in bony fish
Mouth: open
Floor of buccal cavity
Volume of buccal cavity
Pressure in buccal cavity (relative to environment)
Opercular valve
Direction of water movement

Answer 2

Mouth: open
Floor of buccal cavity: downwards
Volume of buccal cavity: increased
Pressure in buccal cavity (relative to environment):lower
Opercular valve: closed
Direction of water movement: into buccal cavity

Question 3

ventilation mechanism in bony fish
Mouth: closed
Floor of buccal cavity
Volume of buccal cavity
Pressure in buccal cavity (relative to environment)
Opercular valve
Direction of water movement

Answer 3

Mouth: closed
Floor of buccal cavity: upwards
Volume of buccal cavity: decreased
Pressure in buccal cavity (relative to environment): incresaed
Opercular valve : open
Direction of water movement: backwards over gill fillanents

Question 4

mechanism of ventilation in carilaginous fish eg. sharks and rays

Answer 4

rely on continual movment known as ram ventilation

Question 5

blood flow in bony fish is

Answer 5

countercurrent

Blood in the lamellae flows in the opposite direction to the water flowing across the gill surfaces.

Equilibrium not reached.
Concentration gradient all way along gill surface.
Diffusion takes place all way along gill surface.
Higher surface area : vol.
Faster rate of diffusion

Question 6

Blood flow Cartilaginous fish

Answer 6

Blood flow in the lamellae is in the same direction as the water flow across the lamellae. Parallel.

Equilibrium reached halfway along gill surface.
Diffusion stops once equilibrium is reached.
Lower surface area : vol.
Slower rate of diffusion

Question 7

how does tips of ajacent fillaments overlapping make exchange in fish effective

Answer 7

• Tips of gill filaments overlap.
• Increases resistance to water flow over gill surfaces.
• Slows water down.
• Water / gill contact time greater. Longer time for O2 to diffuse into blood.

Question 8

how do you describe ventilation in a fish vs a mamal

Answer 8

fish : across (one directio)
mamals: in and out (two directions)

Question 9

Fish anatomey draw and label

Answer 9

under opercular flap you have the fill arches covered in overlapping gill filaments that are aranged in stacks aka gill plates the fillaments have gill lamellae with cappilary networck.

mouth cavity known as buccal cavity towards back known as operculum
inside of the opercular flap is the opercular valve

Question 10

opercular valves can … and …..

Answer 10

close and open

Question 11

buccal cavity can … and ….

Answer 11

expand and constrict