Lecture 4

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Questions and Answers

What is the function of chewing food in the mouth?

Increases surface area and forms a food bolus (correct)

Activates amylase for carbohydrate breakdown

Creates an acidic environment for enzyme activation

Facilitates mixing and breakdown of food in the stomach

Where is the pyloric sphincter located?

In the body of the stomach

In the fundus of the stomach

In the cardia of the stomach

In the antrum of the stomach (correct)

What is the function of pepsins in the stomach?

Activate amylase for carbohydrate breakdown

Break down proteins into peptides (correct)

Create an acidic environment for enzyme activation

Facilitate mixing and breakdown of food

What is the pH range of the stomach?

1.5-2 Signup and view all the answers

What covers the surface of the stomach and protects it from HCl and potential damage?

Mucus and an alkaline bicarbonate fluid Signup and view all the answers

Which cells respond to acetylcholine, histamine, and gastrin in the stomach?

Oxyntic cells Signup and view all the answers

What is the function of intrinsic factor in the stomach?

Binding to vitamin B12 and aiding its absorption Signup and view all the answers

What is the role of the pancreas in the small intestine?

Producing bicarbonate for buffering chyme Signup and view all the answers

What is the main function of villi in the small intestine?

Increasing the surface area for absorption Signup and view all the answers

How often are enterocytes replaced in the small intestine?

Every 3-5 days Signup and view all the answers

Where does fat travel through after being absorbed in the small intestine?

Lymphatic system Signup and view all the answers

What is the purpose of the lymphatic system in fat absorption?

To communicate with the blood system Signup and view all the answers

Which cells continuously proliferate in the small intestine?

Crypt cells Signup and view all the answers

How does nutrient absorption primarily occur in the small intestine?

In brush border of enterocytes Signup and view all the answers

What is the main role of lacteal in the small intestine?

To transport fats through lymphatic vessels Signup and view all the answers

What happens to glucose and amino acids once they are broken down in the small intestine?

They bypass liver and enter circulation through thoracic duct Signup and view all the answers

Study Notes

Digestion Process

Chewing food in the mouth breaks it down into smaller pieces, increasing the surface area for enzyme action.
The pyloric sphincter, located between the stomach and small intestine, regulates the flow of food into the small intestine.

Stomach Function

Pepsins, enzymes in the stomach, break down proteins into smaller peptides and amino acids.
The stomach has a pH range of 1.5-3.5, creating an acidic environment for digestion.
Mucous produced by epithelial cells covers the stomach surface, protecting it from HCl and potential damage.

Cellular Function in the Stomach

G cells, enterochromaffin-like cells, and D cells respond to acetylcholine, histamine, and gastrin in the stomach, regulating digestion and secretion.
Intrinsic factor, produced by parietal cells, helps absorb vitamin B12 in the stomach.

Small Intestine Function

The pancreas secretes digestive enzymes into the small intestine to break down carbohydrates, proteins, and fats.
Villi in the small intestine increase the surface area for nutrient absorption.
Enterocytes, the absorptive cells lining the small intestine, are replaced every 2-4 days.

Fat Absorption

After being absorbed in the small intestine, fat travels through lacteals, the lymphatic vessels, to the bloodstream.
The lymphatic system plays a crucial role in fat absorption and transport.

Nutrient Absorption

Nutrient absorption primarily occurs through facilitated diffusion and active transport in the small intestine.
Lacteals, the lymphatic vessels, absorb dietary fats and transport them to the bloodstream.
Glucose and amino acids, broken down in the small intestine, are absorbed into the bloodstream and transported to the liver for processing.

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Description

Test your knowledge on the anatomy and function of the digestive system, including the process of food breakdown from the mouth to the stomach. This quiz covers topics such as the chewing of food, formation of bolus, muscle layers in the stomach, and the role of enzymes in digestion.