Which muscles of the tongue are responsible for changing its shape for speech and swallowing?
Circumvallate muscles
Extrinsic muscles
Salivary muscles
Submandibular muscles
Intrinsic muscles
The Correct Answer is E
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.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
A. To speed up digestion:Rapid dumping of chyme would actually decrease digestive efficiency. Controlled release allows for thorough mixing with pancreatic and biliary secretions. This ensures that chemical hydrolysis is complete before the chyme moves further distally.
B. To increase stomach storage capacity:Gastric emptying rate does not directly change the anatomical capacity of the stomach. The stomach expands through receptive relaxation during ingestion. Emptying is regulated to match the processing rate of the duodenum.
C. To ensure the small intestine is not overwhelmed:The duodenum has a limited capacity to neutralize acid and emulsify fats. Small, controlled boluses of chyme prevent mucosal damage and osmotic imbalances. This regulation is maintained by the enterogastric reflex.
D. To allow absorption of nutrients in the stomach:Nutrient absorption occurs almost exclusively in the small intestine. Holding chyme in the stomach longer does not significantly increase nutrient uptake. The delay is purely for mechanical and chemical processing efficiency.
Correct Answer is B
Explanation
A. It digests triglycerides with bile:Bile is synthesized by hepatocytes and secreted into the duodenum, not the stomach. Triglyceride emulsification occurs distal to the pyloric sphincter. The gastric environment is too acidic for biliary salts to function effectively.
B. It stores food and gases prior to chyme formation:The fundus is the superior, dome-shaped portion of the stomach that accommodates ingested boluses through receptive relaxation. It serves as a physiological reservoir for undigested food and accumulated digestive gases. It allows for gradual processing into chyme.
C. It produces intrinsic factor for protein absorption:While parietal cells in the fundus and body secrete intrinsic factor, this glycoprotein is specifically required for vitamin B12 absorption in the ileum. It is not involved in the proteolytic cleavage of proteins. Protein digestion requires pepsin.
D. It initiates absorption of nutrients:The gastric mucosa lacks the specialized villi and microvilli necessary for significant nutrient uptake. Absorption is almost exclusively a function of the small intestinal enterocytes. The fundus is primarily a site for storage and mechanical processing.
E. It absorbs vitamin B12 directly:Vitamin B12 cannot be absorbed in the stomach; it must first bind to intrinsic factor. The resulting complex travels to the terminal ileum for receptor-mediated endocytosis. Direct gastric absorption of this vitamin does not occur.
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