The External Environment Within

Questions and Answers

What is the primary function of the mouth in the gastrointestinal tract?

Absorption of nutrients

Mechanical breakdown and enzymatic digestion of food (correct)

Hydrolysis of food

Propelling food into the esophagus

What is the term for the enzymatic breakdown of food?

Hydrolysis (correct)

Morcellation

Mechanical digestion

Biochemical digestion

What is the purpose of breaking down food in the mouth?

To prepare food for absorption in the bloodstream

To kill bacteria in food

To create a bolus that can be swallowed (correct)

To make food more palatable

What is the primary function of the esophagus?

To propel food into the stomach Signup and view all the answers

What is the main function of the stomach in the gastrointestinal tract?

To break down food into smaller particles Signup and view all the answers

Where does food go after being swallowed?

The esophagus Signup and view all the answers

What is the name of the fluid substance that is formed in the stomach after breaking down the bolus?

Chyme Signup and view all the answers

What happens to food in the stomach?

It is further broken down through enzymatic digestion Signup and view all the answers

What is the term for the sphere of digested food?

Bolus Signup and view all the answers

What is the main function of the small intestine?

To absorb nutrients into the bloodstream Signup and view all the answers

Why is the gastrointestinal tract considered 'not you'?

Because it interacts with the external environment Signup and view all the answers

What is the other name for the large intestine?

Colon Signup and view all the answers

What is the main function of the large intestine?

To absorb water, ions, and vitamin K Signup and view all the answers

What is the function of the rectum in the gastrointestinal tract?

To store food until it is ready to be expelled from the body Signup and view all the answers

Which of the following is NOT one of the accessory organs involved in digestion?

Kidney Signup and view all the answers

What is the final process by which waste is expelled from the body?

Expulsion Signup and view all the answers

Study Notes

Gastrointestinal Tract Overview

The gastrointestinal tract is not entirely part of our body, as food we eat passes through our gastrointestinal tract, which is considered an external environment.

Mouth (Oral Cavity)

The first place food goes to is the mouth (oral cavity).
Main functions in the mouth: • Chewing (morcecation of food) • Hydrolysis (enzymatic digestion or breakdown of food)
Goal: to create a bolus (a sphere of digested food) that can be swallowed.

Esophagus

After swallowing, food passes through the esophagus.
The esophagus just propels the bolus down to the next structure, without modifying it.

Stomach

The stomach receives the bolus and performs: • Churning (physical breakdown of food) • Hydrolysis (enzymatic breakdown of food) • Storage of food if it's not time to pass it on
Goal: to create chyme (a fluid substance) that can be passed on to the intestines.

Intestines

The intestines receive the chyme and are divided into: • Duodenum • Small intestine (with three parts, to be discussed in a subsequent video) • Large intestine (also known as the colon)
Main functions in the intestines: • Hydrolysis • Absorption of nutrients in the small intestine • Absorption of water, ions, and vitamin K in the large intestine

Rectum and Anus

The rectum stores the processed food until it's time to expel it.
The anus is the final exit point for the food through expulsion.

Accessory Organs

Other organs involved in digestion include: • Liver • Gallbladder • Pancreas (to be discussed in subsequent videos)