The Importance of Animal Body Fluids

The Relationships among Body Fluids

Types of Regulation and Conformity

Natural Aquatic Environments

Natural Terrestrial Environments

Organs of Blood Regulation

• The osmotic U/P ratio is an index of the action of the kidneys in osmotic regulation
• The effects of kidney function on volume regulation depend on the amount of urine produced
• The effects of kidney function on ionic regulation depend on ionic U/P ratios

Food and Drinking Water

• Salty drinking water may not provide H₂O
• Plants and algae with salty tissue fluids pose challenges for herbivores
• Air-dried foods contain water
• Protein-rich foods can be dehydrating for terrestrial animals

Metabolic Water

• Metabolic water matters most in animals that conserve water effectively
• BOX 27.1 Net Metabolic Water Gain in Kangaroo Rats

Cell-Volume Regulation

From Osmolytes to Compatible Solutes: Terms and Concepts