Answers Lab11 DigestiveAnatomy

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R E V I E W

S H E E T

NAME ____________________________________
EXERCISE

LAB TIME/DATE _______________________

38

Anatomy of the
Digestive System
General Histological Plan of the Alimentary Canal
1. The general anatomical features of the alimentary canal are listed below. Fill in the table to complete the information.

Wall layer

Subdivisions of the layer
(if applicable)

Major functions

mucosa

1) epithelium; 2) lamina propria;
3) muscularis mucosa

absorption secretion submucosa

(not applicable)

vascular supply for mucosa; protection churning; mixing; propulsion of food along the tract

muscularis externa

1) circular layer
2) longitudinal layer
(not applicable)

serosa or adventitia

protection and anchoring for adventitia; reduction of friction for abdominal organs by serosa

Organs of the Alimentary Canal
2. The tubelike digestive system canal that extends from the mouth to the anus is known as the alimentary canal or the gastrointestinal (GI)

tract.

3. How is the muscularis externa of the stomach modified? It has a third (obliquely oriented) muscle layer.
___________________________________________________________________________________________________
How does this modification relate to the function of the stomach? Vigorous churning activity occurs here.
___________________________________________________________________________________________________
4. What transition in epithelial type exists at the gastroesophageal junction?

Changes from stratified squamous (esophagus) to

simple columnar (stomach)
___________________________________________________________________________________________________

How do the epithelia of these two organs relate to their specific functions? The esophagus is subjected to constant abrasion
(stratified squamous is well adapted for this). The stomach has secretory (and some absorptive) functions and is better protected from acid.