Final answer:
The statement is false; dehydration reduces salivation to conserve water, contrary to the suggestion that it increases saliva secretion.
Step-by-step explanation:
The statement that the secretion of saliva generally increases when there is a decrease in the total volume of body water is false.
The autonomic nervous system regulates the secretion of saliva, with the parasympathetic nervous system primarily responsible for maintaining salivation for comfort.
When you're eating, food chemicals stimulate taste receptors on the tongue, sending impulses to the brain stem that increase salivation.
However, dehydration actually causes salivation to be reduced, not increased, because water conservation is a priority for the body when total body water volume is low, and this induces a feeling of dry mouth.
This mechanism prompts the thirst response, encouraging the intake of fluids to restore homeostasis.