BPK 105 Study Guide - Final Guide: Pharyngeal Muscles, Gastrointestinal Tract, Serous Membrane

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Module 11 - Study Guide
Study Guide
Digestive System Structure and Function (Figure 16.2)
- The digestive system functions are all focused on food. Its ingestion, entry into the body,
its digestion, breakdown into small molecules and its absorption, movements of small
molecules across the epithelial lining into circulation.
- The gastrointestinal tract (GI) is made up of the stomach, small intestine, and large
intestine. Figure 16.2 provides an overview of the commonalities we will find in the layers
of the gastrointestinal tract.
- The inner mucosal layer interacts with the food bolus as it moves through the tract. It
is designed to resist abrasion (esophagus) or secrete products to facilitate digestion
(stomach, small intestine) and absorption (small intestine).
- The submucosal layer contains connective tissue that surrounds nerves and blood
vessels. This layer houses important components that control the rate of digestion in
response to the presence of different food products.
- The muscularis contains two layers of smooth muscle. These layers contract and
relax rhythmically to facilitate mixing of food with enzymes and other secretions.
Their contraction also helps this mixture move forward down the tube. Between the
muscle layers we can see more nerves, which help control these contractions.
- The outer serosa is connective tissue that helps to maintain the shape and structure
of the various organs.
Swallowing
-Deglutition (swallowing) involves a combination of voluntary and reflex muscle
actions. The skeletal muscles in the tongue form a bolus of food and push it against the
roof of the mouth (hard palate) and onto the back of the mouth (oropharynx). The
bolus of food contacting the oropharynx stimulates the reflexive closure of the larynx
by the epiglottis and contraction of the pharyngeal constrictor muscle. As food
moves down the esophagus, there is a wave of relaxation that precedes the bolus and
a wave of contraction that follows the bolus of food, squeezing it through the
esophagus into the stomach.
Regulation of Stomach Secretions
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Document Summary

The digestive system functions are all focused on food. Its ingestion, entry into the body, its digestion, breakdown into small molecules and its absorption, movements of small molecules across the epithelial lining into circulation. The gastrointestinal tract (gi) is made up of the stomach, small intestine, and large intestine. Figure 16. 2 provides an overview of the commonalities we will find in the layers of the gastrointestinal tract. The inner mucosal layer interacts with the food bolus as it moves through the tract. It is designed to resist abrasion (esophagus) or secrete products to facilitate digestion (stomach, small intestine) and absorption (small intestine). The submucosal layer contains connective tissue that surrounds nerves and blood vessels. This layer houses important components that control the rate of digestion in response to the presence of different food products. The muscularis contains two layers of smooth muscle . These layers contract and relax rhythmically to facilitate mixing of food with enzymes and other secretions.

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