Question

Secretion of saliva increases when 

A. Touch receptors in the mouth are stimulated. 

B. The mouth is flushed with acid fluids with a pH of about 4. 

C. A subject thinks of unappetizing food. 

D. Vomiting is imminent. 

E. Their sympathetic nerve supply is stimulated.

Answer 1

A. True Food, foreign bodies and the dentist are effective stimuli. 

B. True E.g. lemon juice; saliva is a useful buffer to protect teeth from acid. 

C. False Thinking of appetizing food results in salivary secretion by a conditioned reflex; conversely, thinking of unappetizing food inhibits secretion. 

D. True Saliva helps to buffer the acid vomitus when it reaches the mouth. 

E. True Sympathetic stimulation produces a scanty viscid juice; parasympathetic stimulation produces a copious watery juice.