MCQs on DEGLUTITION
DEGLUTITION (an important topic for FCPS part 1 exam which is very deficient in the books that we study)
MCQ 1: Third Part of deglutition is
a. Gravity dependant
b. Vagally stimulated
c. Surface of food is bolus
MCQ 2: Regarding deglutition:
a. Contraction of cricophyrangeus
b. Soft palate moves upward
c. Co-ordinated reflex
d. Inspiration cessation
MCQ 3: Regarding gastroesophageal sphincter
a. Its a true anatomic sphincter
b. Its pressure increases in pregnancy
c. its pressure decreases in achalasia
d. It relaxes during swallowing
MCQ 4: In Swallowing stage
a. Palantopharngeus muscles moves
b. Larynx moves down
c. Palate move downwards
d. Palatopharngeal folds move medially
DEGLUTITION (SWALLOWING): Deglutition is the process by which food is passed from mouth through the pharynx and esophagus into the stomach as a result of reflex phenomena. Degultition can be divided into three parts:
(1) VOLUNTARY STAGE:
Bolus ready for swallowing → Pressure of the tongue upward and backward against the palate → Bolus forced by tongue into the pharynx.
(2) PHARYNGEAL STAGE (Involuntary):
Bolus in posterior mouth stimulates swallowing receptor area around the opening of pharynx → Afferent impulses are transmitted through 9th (glossopharyngeal) and 10th (vagus) cranial nerves to swallowing center in medulla and lower pons → Efferent impulses pass to pharynx and upper esophagus to cause the following effects:
a. Soft palate is pulled upward to close the posterior nares.
b. Palatopharungeal folds are pulled medially to form a saggital slit which allows properly masticated food to pass and prevents large particles to pass through it.
c. Peristalsis begins in the pharynx which propels the food from pharynx into the esophagus.
(3) ESOPHAGEAL STAGE (Involuntary):
During this stage, food moves through esophagus into the stomach. Three factors participate in it:
a. Primary peristalsis: It is continuation of the peristaltic waves that begin in the pharynx. It propels most of the bolus into the stomach.
b. Secondary peristalsis: The remaining bolus in the esophagus causes distension of the esophagus → Vagal reflex occurs which initiates secondary peristalsis in esophagus, and causes receptive relaxation of LES → The remaining bolus is passed into the stomach.
c. Gravity (in standing position): Gravity increases the rate of passage of food through the esophagus but the movement of food in esophagus does not depend upon gravity; food will still reach the stomach even if the person is upside down.
a. The swallowing reflex is coordinated in medulla. Fibers in vagus and glossopharyngeal nerves carry information between the GIT and the medulla.
b. The soft palate moves upward to close the posterior nares.
c. The secondary peristaltic wave clears the esophagus of any remaining food.
d. Gravity accelerates the rate of passage of food through the esophagus but the passage of food through the esophagus is not dependent on gravity.
e. The gastroesophageal sphincter relaxes during swallowing.
f. During swallowing, the Palatopharngeal folds move medially