True or False
Cholecystokinin (CCK) stimulates the release of bile from the gallbladder and pancreatic enzymes.

A. Circumvallate muscles:These are not muscles but rather large, circular papillae located in a V-shaped row at the posterior aspect of the tongue. They contain numerous gustatory receptors but lack contractile properties for lingual movement. They do not influence the organ's shape.

B. Extrinsic muscles:These muscles, including the genioglossus and hyoglossus, originate from structures outside the tongue and insert into its substance. They are primarily responsible for the gross movement and positioning of the tongue, such as protrusion and retraction. They move the tongue as a whole.

C. Salivary muscles:There is no anatomical classification for muscles specifically designated as salivary muscles in the human body. Salivary secretion is controlled by the autonomic nervous system acting on glandular epithelial cells, not by specialized lingual muscles. This is not a valid anatomical term.

D. Submandibular muscles:This term typically refers to the muscles of the floor of the mouth, such as the mylohyoid, which support the tongue and hyoid bone. While they assist in the elevation of the tongue during swallowing, they do not reside within the tongue. They do not change its internal shape.

E. Intrinsic muscles:These muscle fibers are located entirely within the tongue and are not attached to bone. They are arranged in longitudinal, transverse, and vertical planes, allowing the tongue to curl, flatten, or thicken for complex articulation and deglutition. They are the primary effectors for changing tongue shape.

A. Lysozyme:This enzyme functions as an antimicrobial agent by cleaving the peptidoglycan walls of certain bacteria. It provides a non-specific immune defense within the oral cavity. It possesses no catalytic activity toward carbohydrates or starches.

B. Salivary amylase:Also known as ptyalin, this enzyme initiates the hydrolysis of complex polysaccharides into smaller oligosaccharides like maltose. It operates at an optimal neutral pH within the mouth. This is the first step of chemical carbohydrate digestion.

C. Pepsin:This protease is secreted by gastric chief cells as pepsinogen and is activated by hydrochloric acid in the stomach. It is specialized for the cleavage of peptide bonds in proteins. It does not participate in carbohydrate breakdown.

D. Salivary lipase:This enzyme is secreted by von Ebner’s glands on the tongue to begin the hydrolysis of triglycerides. It targets dietary lipids rather than carbohydrates. Its activity continues within the stomach due to its acid-stable nature.