Detail the pathway of oxygenated water in the ventilation of a fish. Name and briefly describe the mechanism by which gaseous exchange takes place.
Oxygen rich water enters the mouthdue to buccal expansion > water is accelerated across the gill filamentsdue to simultaneous contraction of the buccal cavity and expansion of the opercula > gaseous exchange takes place via a countercurrent system.The countercurrent system is the name given to the mechanism used for gaseous exchange in afish, whereby the direction of travel for oxygenated water and blood is opposite. This means that high oxygenatedwater untakes gaseous exchange with already oxygenated blood, while water witha lower oxygen content exchanges will less well oxygenated blood. This networkmaintains an active concentration gradient for a longer period of time.
OF
Related Biology A Level answers
All answers ▸Cells go through a series of stages in order to replicate themselves, called mitosis. Briefly describe each stage of mitosis. (8)
Using mendelian genetics, explain how two brown eyed parents can have a blue eyed child. Which of the alleles is dominant? You may use a graph to support your explanation (Tip: Assume a simple dominance and inheritance )
In genetics, what is sex linkage and give an example
What are the important similarities and differences between RNA and DNA?