BIO 3302 Lecture Notes - Lecture 14: Fish Gill, Teleost, Amphiprioninae
13 Dec 2016
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LECTURE 14 – IONIC WATER BALANCE
Osmoconformer? Lobster or Cray fish?
• Lobster found in ocean cant be osmoconformer in freshwater
Drink? Goldfish or clownfish?
• Clownfish - in salt water, goldfish is gaining water would not drink
Chloride cell vs acid secreting MR cell.
• Both ionocytes
• Chloride cell - excretion of salts
o Found in gills of marine teleost fish
o Need to excrete salts bc ion gain
• Mitochondria enriched cell - takes up sodium
o Gills of freshwater teleost fish
o Need to input salts bc losing ions in freshwater
• iooytes trasportig salts i opposite diretios …
Fish gill represents compromise between needs for gas transfer and those for salt/water balance.
• Large SA benefits gas transfer but more difficult to maintain salt valves by obligatory salt
movement occurring dependent on SA
o More obligatory movements of salt or water need to be accommodated for.
o Require ATP to gain or pump out salts
o Cuts down on energetic cost on gill
o Compromise is called osmorespiratory compromise
Hagfish is an osmoconformer. What can you infer about its evolutionary history from this
observation?
• Only vertebrate blah
• Hagfish are located in ocean
• Evolutionary history:
o Never been in freshwater - never made transition into freshwater envt
o Teleost fish, elasmobranchs - salt conc lower than that of envt bc at one point entered
freshwater lowered ion conc so easier to not lose salts AND then re-entered marine
envt.
ION AND WATER BALANCE IN TERRESTRIAL ENVT
• Problem: animals found in terrestrial are aquatic animals (70% water) in dry envt
o Environmental water loss (EWL)
• Can occur across surface of body OR respiratory surface
• Make body surface less permeable so less water loss (RAINCOAT)
o Waste excretion requires water
o Water conservation is primary concern
• Solutions:
o Minimize obligatory losses I →less permeable integuement
• Thin layers of lipids
▪ Ex. Mammals - in spaces between cells in superficial skin layer
• cuts down EWL (birds also use lipids)
▪ Amphibians, reptiles - cutaneous water loss most significant
• Do’t use lipids
o Minimize obligatory losses II - water recovery from exhaled air
find more resources at oneclass.com
find more resources at oneclass.com
• Birds and mammals have high respiratory rate and increases amount of
evaporation that can occur
▪ Also they maintain a higher T than envt bc warm air holds more water than
cool air
▪ H temp air needs more water than cool T air
▪ When inhale cool dry air - needs to be warmed and humidified when going
into lungs
• Achieved by adding heat and water to air when inhaled
▪ When exhale- represents a huge loss of heat AND WATER
▪ Mammals and birds use a counter current method to maintain heat and
water
• Pass over nasal mucosa to =humidify it (100% relative humidity)
• And therefore, cools nasal mucosa
▪ As exhale
• Warm air passes over nasal mucosa and water condenses on nasal
mucosa and regain of water for animal
• Air being exhaled is now at a warm temp but by going outside
becomes cooler
▪ Breathing through mouth still humidifies mouth but not as much AND when
exhaling LOSING water from this mech
▪ Huas do’t have useful eh ot log asal passages to irease SA
AND mouth has no advantage of regaining water loss.
• Value of lipids:
o Tree frogs have permeable skin
o (phyllo medusa - waxy frog)
• Using lipids cuts down on EWL on body surface
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Lobster found in ocean cant be osmoconformer in freshwater. Goldfish or clownfish: clownfish - in salt water, goldfish is gaining water would not drink. Fish gill represents compromise between needs for gas transfer and those for salt/water balance. Ion and water balance in terrestrial envt: problem: animals found in terrestrial are aquatic animals (70% water) in dry envt, environmental water loss (ewl) Can occur across surface of body or respiratory surface: make body surface less permeable so less water loss (raincoat) Solutions: waste excretion requires water, water conservation is primary concern, minimize obligatory losses i less permeable integuement, thin layers of lipids, ex. If live in fresh water - easy just drink whatever. Seawater as a source of water: marine mammals - net loss of water, marine teleost fish - drink like a fish and benefit from sea water by getting rid of salts from chloride cells. Salt-secreting glands of marine reptiles and birds - release salts by concentrated urine.
