Fish gas exchange

Oxygen content in water rarely exceeds what percentage

• 20%

• 19%

• 0.8%

• 2%

True or false, in terms of volume, a fish will need to move more water over its gills to obtain oxygen vs. a mammal breathing air

• False

• True

Gills are adapted for efficient gas exchange due to the following reasons (select all that apply)

• Broccoli shaped alveoli provide large surface area

• Gills provide a large surface area to volume ratio

• Gills are very thin, making a short diffusion distance for gases

• A high concentration gradient between the gaseous content of the blood versus the gaseous content of the water

Water moves across the gill lamellae in the opposite direction to the blood flowing through them, this is known as a

• Gill lamellae mechanism

• Opercular suction pump

• Countercurrent exchange mechanism

• Bony gill arch current mechanism

True or false, bony fish must always be moving to have water flowing over the gills

• False

• True

Fish gills are delicate, they are protected by a bony flap called an operculum, it also provides two ventilatory pumps, they are known as

• Gill lamellae pumps

• Opercular suction pumps

• Blood vessel pumps

• Buccal pressure pumps