Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

23. The Digestive System

Introduction to the Digestive System

Anatomy & Physiology

23. The Digestive System

Introduction to the Digestive System

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Problem 3d

Textbook Question

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
The mucosa of the esophagus, pharynx, and oral cavity contains simple squamous epithelium to protect it from abrasion.

Verified step by step guidance

Understand the structure and function of the mucosa in the esophagus, pharynx, and oral cavity. The mucosa is the innermost layer of these structures and is responsible for protection against mechanical stress, such as abrasion from food particles.

Recall the type of epithelium found in areas subject to abrasion. Stratified squamous epithelium, not simple squamous epithelium, is typically found in these regions because its multiple layers provide better protection against mechanical damage.

Analyze the statement: 'The mucosa of the esophagus, pharynx, and oral cavity contains simple squamous epithelium to protect it from abrasion.' This is false because simple squamous epithelium is a single layer of flat cells, which is not sufficient for protection against abrasion.

Correct the false statement: Replace 'simple squamous epithelium' with 'stratified squamous epithelium' to make the statement true. The corrected statement should read: 'The mucosa of the esophagus, pharynx, and oral cavity contains stratified squamous epithelium to protect it from abrasion.'

Review the corrected statement and ensure it aligns with the anatomical and physiological characteristics of these regions. Stratified squamous epithelium is indeed the appropriate tissue type for protection in these areas.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Mucosa Structure

The mucosa is the innermost layer of the gastrointestinal tract, consisting of epithelial tissue, connective tissue, and a thin layer of muscle. In the esophagus, pharynx, and oral cavity, the mucosa is primarily composed of stratified squamous epithelium, which provides protection against mechanical abrasion from food and other substances.

Epithelial Tissue Types

Epithelial tissues are classified based on the number of cell layers and the shape of the cells. Simple squamous epithelium consists of a single layer of flat cells, which is not suitable for areas subject to friction. In contrast, stratified squamous epithelium has multiple layers, making it more resilient to wear and tear, particularly in the esophagus and oral cavity.

Function of Stratified Squamous Epithelium

Stratified squamous epithelium serves a critical protective function in areas exposed to mechanical stress. This type of epithelium can withstand abrasion and is essential in the esophagus, pharynx, and oral cavity, where food particles can cause damage. Understanding this function is key to correcting the statement regarding the mucosal structure in these regions.

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Master Organs of the Digestive System with a bite sized video explanation from Bruce Bryan

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Related Practice

Multiple Choice

Which of the following are true for digestion:

I. Chemical digestion begins in the stomach.

II. Digestion involves breaking down food both physically and chemically.

III. Mechanical digestion increases the surface area of ingested food.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

The muscularis externa of most of the alimentary canal consists of inner circular and outer longitudinal layers of smooth muscle.

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Multiple Choice

True or False: if false, choose the answer that best corrects the statement.

While the accessory organs contribute important digestive enzymes and fluids, all digestions and absorption of nutrients takes place in the alimentary canal/GI tract.

Four organs are listed below. During food’s path through the alimentary canal, the partially digested food passes through the lumen of each of these organs except:

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

b. The esophageal and pharyngeal phases of swallowing are mediated by the swallowing reflex of the brainstem and the enteric nervous system.

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Multiple Choice

The enteric nervous system is the in-house nerve supply of the alimentary canal.

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Textbook Question

Make a simple line drawing of the organs of the alimentary canal and label each organ. Then add three labels to your drawing—salivary glands, liver, and pancreas—and use arrows to show where each of these organs empties its secretions into the alimentary canal.

A drop in pH below 4.5 in the duodenum stimulates the secretion of

(a) Secretin

(b) Cholecystokinin

(d) All of these