Chapter 7 Fish and Insects Flashcards
What are the two types of fish? What is the different between the two?
Bony and non bony
Bony contain a skeleton of bone
What challenges to fish meet?
High metabolic demand
Large surface area to volume ratio
Lower concentration of O2 in the ocean
So must have a very efficient exchange system
What is the general root of water in fish?
In through the mouth, to the opercular cavity where the gills remain
Through the gill lamellae, out of the operculum
What are the components of gills?
Contain lots of gill arches
These arches contain extension called gill filaments, look like feathers
The filaments contain gill lamellae which is where exchange occurs
How are gill lamellae adapted for gaseous exchange?
Short diffusion distances between the lamellae and the walls to the blood
An extensive network of capillaries to increase the concentration gradient
Lots of gill lamellae to increase the surface area of exchange
What type of system is made between the blood and water in fish? What is it an why is it useful?
A counter current system
The direction of blood flow is opposite to the direction of water movement
Allows a concentration gradient to be maintained across the whole length of the gill lamellae, instead of equilibrium being reached
How is the flow of water maintained in non-bony fish?
Caused my the movement of the fish
What is the mechanism in which bony fish take in water for gaseous exchange?
The mouth of the fish opens, causing water to move in. This increases the volume of the buccal cavity, which decreases pressure. The floor of the buccal cavity drops, increasing water availability.
The operculum shuts, which increases the volume of the opercular cavity, decreasing pressure.
At the same time, the roof of the buccal cavity lifts, causing water to move in the opercular cavity over the gills.
The mouth of the fish closes, and the operculum opens. The sides of the opercular cavity squeezes inwards increasing pressure, forcing water out of the operculum.
Where does gaseous exchange occur in insects and why?
Insects contain an exoskeleton which is impermeable to gases such as oxygen and carbon dioxide
Therefore, gaseous exchange must occur at the spiracles, opening in the insect exoskeleton
What is the structures of gaseous exchange in insects?
Spiracles- holes in the exoskeleton
Trachea- A long tube with chitin for support
Tracheole- Elongated cells which lead to tissues which require oxygen
How does insect transport actually work, specifically?
Delivers gases directly to cells through the tubes, finally the tracheoles
When and how does an insect increase gaseous exchange?
When very active, more oxygen needed
Cells where the tracheole contains tracheal fluid respire anaerobically, building up lactic acid
This decreases water potential of the cells, causing tracheal fluid to move into cells
This increases the surface area available for gaseous exchange
Where can water be lost in insects?
From tracheal fluid and moisture of the trachea walls
How do insects limit water loss?
Contain sphincter muscles which closes spiracles, so reduce water loss by diffusion
Tracheal fluid is impermeable to gas exchange, decreasing surface area for exchange
What is tracheal fluid?
Fluid in the trachea and tracheoles which limits penetration of air for diffusion
Gases can still diffuse through, but much more slowly
