15 Questions
Which factors in saliva destroy bacteria by chelating iron necessary for bacterial growth?
Thiocyanate ions and lactoferrin
What is the main control pathway for salivary secretion?
Parasympathetic pathways
What initiates hunger pangs or mild pain in the pit of the stomach?
Rhythmic peristaltic contractions
What factors can initiate enterogastric inhibitory reflexes in the duodenum?
Degree of distension of the duodenum
What type of wave in the stomach wall is initiated by the gut wall and provides powerful peristaltic action potential?
Basic electrical rhythm
Which enzyme breaks down and converts polysaccharides to disaccharides and monosaccharides in the mouth?
Salivary amylase
Which cranial nerve innervates the chewing muscles?
CN-V (5th cranial nerve)
What determines the type of food that a person preferentially seeks?
Appetite
What is the principal determinant of the amount of food a person ingests?
Intrinsic desire for food (hunger)
What process involves the voluntary taking of food into the digestive tract through the oral cavity?
Ingestion
Which muscle is involved in the buccal phase of swallowing?
Tongue
What is the primary role of chewing in digestion?
Increasing surface area for digestive enzymes to act upon
What is the daily range of saliva secretion in milliliters?
800 - 1500
Which gland secretes primary secretion containing ptyalin or mucin in a solution of ions?
Submandibular gland
What controls the peristaltic movement of the esophagus?
Medullary centers
Study Notes
Physiology of Chewing and Swallowing
- Chewing process involves muscles such as Masseter, Temporalis, Lateral Pterygoid, and Medial Pterygoid, controlled by brain stem nuclei and taste centers in the brain
- Chewing reflex is initiated by food entering the mouth, leading to a series of muscle contractions and relaxations
- Chewing is important for digestion, especially for fruits and raw vegetables, as it increases the surface area for digestive enzymes to act upon
- Swallowing, or deglutition, involves three phases: buccal, pharyngeal, and esophageal
- The buccal phase is voluntary, moving the food bolus to the oropharynx using the tongue and involving the epiglottis and glottis
- The pharyngeal phase is involuntary and involves stimulation of receptors in the oropharynx, leading to the closure of the mouth, nasopharynx, raising of the larynx, and relaxation of the upper esophageal sphincter
- The esophageal stage involves the closure of the upper esophageal sphincter, opening of the gastroesophageal sphincter, and involuntary peristaltic movement of the esophagus
- The esophagus is controlled by both skeletal and smooth muscles, with peristalsis being controlled by medullary centers
- Saliva, produced by glands such as the parotid, submandibular, sublingual, and buccal glands, plays various roles such as moistening food, beginning digestion, adjusting salt appetite, and helping to wash away bacteria and food
- Saliva contains serous and mucous secretions, with daily secretion ranging between 800 and 1500 milliliters
- Saliva contains potassium and bicarbonate ions, with the submandibular gland secreting primary secretion containing ptyalin or mucin in a solution of ions
- The composition of saliva and its functions make it essential for the process of digestion, acting as a lubricant and aiding in the breakdown of food.
Test your knowledge of the physiology of chewing and swallowing with this quiz. Explore the muscles involved in chewing, the phases of swallowing, the role of saliva in digestion, and more. See how much you know about the intricate processes that allow us to consume and digest food.
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