Page 203 - Physiology and Pathophysiology MNU 2024-2025 نظرى

Clinical pharmacy 2024/2025 Level 2 Pharm D Physiology and Pathophysiology (MD303)

b. Mucus: thick and slippery  lubricates the mouth and the food and assists in

swallowing

c. Lysozyme: Enzyme that lyses or kills many types of bacteria that may be
ingested.

d. Salivary ◼ Splits starch molecules into fragments

amylase: ◼ may account for up to 75% of starch digestion

Small amount
e. Lingual Plays a role in the breakdown of dietary lipid.
lipase: optimally active at an acidic pH  remains active through the

stomach and into the intestine

2- Pharynx:

Swallowing

• The epiglottis moves downward over the larynx  seal off the trachea.

• The upper esophageal sphincter relaxes  allowing the bolus of food to enter the
esophagus.

3- esophagus:

Peristalsis
a. Circular smooth muscle contract behind the bolus.

b. Followed by longitudinal contraction (shortening) of smooth muscle  then
Sphincter open to enter food.
c. After food passes into stomach  lower esophageal sphincter constricts.
Any disease in Sphincter  Make food & acid return to esophagus  esophageal

reflux disease (heart burn)

NB

The only substance secreted by the esophagus is mucus  provides lubrication for the

passage of food & prevent damage to the esophageal wall by coarse food materials.

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