60 Questions
Which type of fish migrate down rivers as adults to spawn in the sea and juveniles back to fresh water to grow?
Catadromous
What is the salinity tolerance range of euryhaline fishes?
SW to FW
Which fish is an example of an anadromous species?
Salmon
What is the main function of the rectal gland in elasmobranchs?
Salt secretion
Which type of fish is known for excreting copious, dilute urine and ion uptake through gill cells?
Freshwater fishes
What is the evolutionary pattern of ion transport regulation in euryhaline salmonids?
Reciprocal regulation
Which organ is involved in salt retention for osmoregulation in coral catfish?
Dendritic organ
What is the osmoregulation strategy of lampreys and teleosts in saltwater?
Hypoionic
Which fish type exhibits reciprocal regulation of ion transport?
Euryhaline fishes
What is the main function of the nasal/lingual salt glands in birds and reptiles?
Salt excretion
What is the salinity range for freshwater?
0.1 to 0.2 ppt
What is the salinity range for hypersaline water?
Greater than 40 ppt
What is the ion concentration of [Mg2+] in saltwater?
54 mmol·L-1
What is the osmolality range of natural fresh salt waters?
0.5 – 10 mosM(per kg water)
Which type of water has a salinity range of 0.5 to 30 ppt?
Brackish water
What is the ion concentration of [Na+] in freshwater?
0.35 mmol·L-1
What is the ion concentration of [SO42-] in saltwater?
28 mmol·L-1
What is the ion concentration of [K+] in freshwater?
0.08 mmol·L-1
What is the ion concentration of [HCO3-] in saltwater?
10 mmol·L-1
What is the ion concentration of [Ca2+] in freshwater?
0.75 mmol·L-1
What is the primary function of osmoconformers in coping with different water compositions?
Their body fluid osmotic pressure changes with the medium
What is the main challenge faced by freshwater animals?
Hyperosmoregulation challenges
What is the role of saltwater ionocytes in marine fishes?
Facilitate active absorption of ions and water across the gut
What distinguishes the kidney design of freshwater animals from that of marine fishes?
Freshwater animals have different kidney design to cope with hyperosmoregulation
What is the key strategy used by elasmobranchs to cope with salt influx?
Retention of solutes like urea and TMAO
What is the primary function of osmoregulators in coping with different water compositions?
Regulate internal osmotic concentrations
What is the role of freshwater ionocytes in fish?
Facilitate low Na+, Cl-, K+ and variable Ca2+ in blood
What is the primary function of marine teleosts and lampreys in coping with different water compositions?
Hyposmoregulation
What is the main role of kidneys in sea water fishes?
Limited role in excreting toxic divalents such as Mg2+, Ca2+, SO42-
What distinguishes the kidney design of marine fishes from that of freshwater animals?
Marine fishes have different kidney design to cope with hyperosmoregulation
What distinguishes euryhaline fishes from stenohaline fishes?
Euryhaline fishes have broad salinity tolerance, from saltwater to freshwater
What is the primary migration pattern of catadromous fish?
Migrate down rivers as adults to spawn in the sea and juveniles back to fresh water to grow
What is the main osmoregulation strategy of lampreys and teleosts in saltwater?
Isosmotic regulation
What is the primary function of the rectal gland in elasmobranchs?
Excreting excess salt from the body
What distinguishes freshwater fishes from saltwater fishes in terms of osmoregulation?
Freshwater fishes are hyperosmotic regulators, excreting copious, dilute urine, while saltwater fishes are isosmotic
What is the evolutionary pattern of ion transport regulation in euryhaline salmonids?
Reciprocal regulation of ion transport
What is the primary role of the nasal/lingual salt glands in birds and reptiles?
Facilitating salt retention for osmoregulation
What distinguishes the kidney design of marine fishes from that of freshwater animals?
Marine fishes have a filtration kidney, while freshwater animals have very long loops of Henle
What is the main challenge faced by freshwater animals according to the text?
High pressure filtration kidney needed for processing nitrogenous wastes
What is the primary function of the Dendritic organ in coral catfish?
Facilitating salt retention for osmoregulation
What is the osmolality range of natural fresh salt waters?
0.5 – 10 mosM(per kg water)
What is the salinity range for hypersaline water?
>40 ppt
What is the primary role of the nasal/lingual salt glands in birds and reptiles?
Salt retention for osmoregulation
What is the main function of the rectal gland in elasmobranchs?
Regulation of osmolarity
What is the ion concentration of [K+] in freshwater?
0.08 mM
What is the main challenge faced by freshwater animals?
Regulating salt influx
What is the evolutionary pattern of ion transport regulation in euryhaline salmonids?
Reciprocal regulation of ion transport
What is the primary migration pattern of catadromous fish?
Migrate down rivers as adults to spawn in the sea and juveniles back to fresh water
What distinguishes euryhaline fishes from stenohaline fishes?
Ability to maintain constant internal osmolarity despite external salinity changes
What is the primary function of osmoregulators in coping with different water compositions?
Regulation of osmolarity
What distinguishes osmoconformers from osmoregulators in fish?
Osmoconformers have body fluid osmotic pressure that changes with the medium
What is the primary role of freshwater ionocytes in fish?
Facilitate low Na+, Cl-, K+ and variable Ca2+ in blood
What is the main osmoregulation strategy of marine teleosts and lampreys in saltwater?
Hyposmoregulation
What distinguishes elasmobranchs in coping with salt influx?
They retain solutes like urea and TMAO
What is the primary function of the rectal gland in elasmobranchs?
Retain solutes like urea and TMAO
What is the main challenge faced by freshwater animals in terms of osmoregulation?
Hyperosmoregulation challenges
What distinguishes the kidney design of marine fishes from that of freshwater animals?
Marine fishes' kidneys play a limited role in excreting toxic divalents such as Mg2+, Ca2+, SO42-
What is the primary function of saltwater ionocytes in marine fishes?
Facilitate active absorption of ions and water across the gut
What is the main strategy used by euryhaline fishes to cope with different water compositions?
Reciprocal regulation of ion transport
What is the primary role of the nasal/lingual salt glands in birds and reptiles?
Excrete excess salts from the body
Study Notes
Strategies for Coping with Different Water Compositions in Fish
- Osmoconformer: body fluid osmotic pressure changes with medium
- Osmoregulator: regulate internal osmotic concentrations
- Ionic Regulation: control body fluid solute composition & osmolarity in fish
- Freshwater animals face hyperosmoregulation challenges
- Freshwater ionocytes and vertebrate kidney design differ from those of marine fishes
- Freshwater ionocytes facilitate low Na+, Cl-, K+ and variable Ca2+ in blood
- Marine fishes use three major strategies for coping with salt influx
- Elasmobranchs retain solutes like urea and TMAO
- Elasmobranchs have specialized mechanisms for urea retention in gills and kidneys
- Marine teleosts and lampreys are hyposmoregulators
- Saltwater ionocytes facilitate active absorption of ions and water across the gut
- Kidneys in sea water fishes play a limited role in excreting toxic divalents such as Mg2+, Ca2+, SO42-
Strategies for Coping with Different Water Compositions in Fish
- Osmoconformer: body fluid osmotic pressure changes with medium
- Osmoregulator: regulate internal osmotic concentrations
- Ionic Regulation: control body fluid solute composition & osmolarity in fish
- Freshwater animals face hyperosmoregulation challenges
- Freshwater ionocytes and vertebrate kidney design differ from those of marine fishes
- Freshwater ionocytes facilitate low Na+, Cl-, K+ and variable Ca2+ in blood
- Marine fishes use three major strategies for coping with salt influx
- Elasmobranchs retain solutes like urea and TMAO
- Elasmobranchs have specialized mechanisms for urea retention in gills and kidneys
- Marine teleosts and lampreys are hyposmoregulators
- Saltwater ionocytes facilitate active absorption of ions and water across the gut
- Kidneys in sea water fishes play a limited role in excreting toxic divalents such as Mg2+, Ca2+, SO42-
Test your knowledge of fish physiology and adaptations to different water compositions with this quiz. Explore the concepts of osmoregulation, ionic regulation, and the specialized strategies used by freshwater and marine fish to cope with varying osmotic pressures.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
