BIO 3302 Lecture Notes - Lecture 13: Fish Gill, Teleost, Amphiprioninae
4 Nov 2017
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Collapsible alveoli to empty lungs effectively, floating rib. High volume of blood, haemoglobin, and myoglobin in the muscle. P50 effect can be either higher or low. Goldfish loses ions across its gills to surrounding fw. A frog sitting on a lily pad loses water by evaporation across its skin. Obligatory - thin skin so not much control. Regulated - response to loss of water from obligatory losses. T or f in the figure to the right, the crab is a stenohaline, hyperionic regulator in half-strength seawater. Cannot tell whether it is hyperionic or not because this figure only shows osmolarity. All evolutionary history in seawater --> body fluids almost matching. Marine chondrichthians (elasmobranchs sharks, skates & rays; chimaerans ratfish); Osmotic pressure similar to environment ions are much smaller, hypoionic. Must get rid of excess salt that is gained mostly at gills. Rectal gland produces a solution that is isoosmotic with body fluids by hyperionic to get rid of ions.
