Digestive System Overview

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Questions and Answers

What is the function of absorption in the digestive process?

Uptake of nutrients by body cells (correct)

Splitting bonds in molecules with water

Breaking down food particles outside of cells

Engulfing food particles by endocytosis

Which type of digestion involves the engulfment of food particles by endocytosis?

Chemical digestion

Extracellular digestion

Absorption digestion

Intracellular digestion (correct)

What is the purpose of specialized compartments in the digestive process of most animals?

To facilitate extracellular digestion

To reduce the risk of digesting own cells and tissues (correct)

To speed up chemical digestion

To prevent the absorption of nutrients

Why do animals with simple body plans have a gastrovascular cavity with one opening?

To function as both mouth and anus Signup and view all the answers

What is the alternative name for a one-way digestive tube with a mouth and an anus?

Complete digestive tract Signup and view all the answers

How does extracellular digestion differ from intracellular digestion?

Extracellular digestion involves breaking down food outside cells Signup and view all the answers

What is the primary function of the liver in the digestive system?

Production of bile Signup and view all the answers

Which organ in the digestive system is responsible for reabsorbing water from undigested food?

Cecum Signup and view all the answers

What is the main function of the colon in the digestive process?

Hosts beneficial bacteria Signup and view all the answers

Which part of the digestive system is responsible for storing feces until defecation?

Rectum Signup and view all the answers

What is an essential role of the large intestine in digestion?

Reabsorb water Signup and view all the answers

Which sphincter controls the elimination of waste material voluntarily?

Outer sphincter Signup and view all the answers

Which organ conducts food from the pharynx down to the stomach by peristalsis?

Esophagus Signup and view all the answers

What is the first stage of digestion that takes place in the oral cavity?

Mechanical digestion Signup and view all the answers

Which organ delivers saliva to lubricate food?

Salivary glands Signup and view all the answers

What enzyme initiates the breakdown of glucose polymers in the mouth?

Salivary amylase Signup and view all the answers

What is the purpose of peristalsis in the digestive system?

Mix food with digestive juices Signup and view all the answers

What is the function of the trachea in relation to food digestion?

Leads to the lungs Signup and view all the answers

What type of muscle is the Internal Anal Sphincter?

Thin muscle Signup and view all the answers

Which sphincter can be voluntarily clenched or unclenched?

External Anal Sphincter Signup and view all the answers

What is the most important source of ATP generation in animals?

Oxidation of energy-rich molecules Signup and view all the answers

Which animal group has the most elaborate adaptations for an herbivorous diet?

Ruminants Signup and view all the answers

Where do animals primarily store excess calories?

Glycogen in the liver and muscles Signup and view all the answers

In what part of the digestion process does the blood glucose level rise after eating?

Reticulum Intestine Signup and view all the answers

How do ruminants like cows and sheep chew their food?

Lacking upper incisor teeth, using lower teeth, tongue, and lips Signup and view all the answers

What are the chambers of the ruminant stomach responsible for digesting cellulose?

Rumen, reticulum, omasum, and abomasum Signup and view all the answers

Which chamber of the ruminant stomach functions as the 'true' stomach?

Abomasum Signup and view all the answers

What does fermentation in the ruminant stomach produce?

Gases that need to be eliminated Signup and view all the answers

Which organ of the digestive system is responsible for absorbing nutrients in ruminants?

Small intestine Signup and view all the answers

Study Notes

Chemical Digestion

Enzymatic hydrolysis splits bonds in molecules with the addition of water.

Absorption and Elimination

Absorption is the uptake of nutrients by body cells.
Elimination is the passage of undigested material out of the digestive compartment.

Food Processing in Specialized Compartments

Most animals process food in specialized compartments to reduce the risk of self-digestion.
Intracellular digestion occurs when food particles are engulfed by endocytosis and digested within food vacuoles.
Extracellular digestion occurs outside of cells in compartments continuous with the outside of the animal's body.

Digestive Systems in Animals

Simple animals have a gastrovascular cavity with one opening that functions as both mouth and anus.
More complex animals have a digestive tube with two openings, a mouth and an anus, called a complete digestive tract or alimentary canal.

Valves in the Digestive System

Valves called sphincters regulate the movement of material between compartments.

The Mammalian Digestive System

The human digestive system consists of the mouth, esophagus, stomach, small intestine, large intestine, rectum, anus, liver, pancreas, and gallbladder.

The Oral Cavity, Pharynx, and Esophagus

Mechanical digestion occurs in the oral cavity, where teeth chew food into smaller particles.
Salivary glands deliver saliva to lubricate food and initiate carbohydrate digestion.
The tongue shapes food into a bolus and helps with swallowing.

Swallowing and Peristalsis

The swallowing reflex and peristalsis move food from the mouth to the stomach.

Elimination of Undigested Waste

The large intestine reabsorbs water from undigested food and processes waste.
The colon is home to many bacteria that aid in digestive processes.
The rectum stores feces until defecation, and the anus is the exit point for waste material.

Ruminant Digestion

Herbivores have fermentation chambers where symbiotic microorganisms digest cellulose.
Ruminant stomach is multi-chambered, consisting of the rumen, reticulum, omasum, and abomasum.
Microbes in these chambers break down cellulose and ferment ingested food.

Energy Balance and Storage

Food energy balances the energy from metabolism, activity, and storage.
Animals store excess calories primarily as glycogen in the liver and muscles.
Energy is secondarily stored as adipose, or fat, cells.

The Liver and Accessory Organs

The liver produces bile, a digestive juice required for the breakdown of fatty components of food.
The liver processes vitamins and fats, synthesizes many plasma proteins, and detoxifies blood.

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Description

Test your knowledge on the key concepts of the digestive system including enzymatic hydrolysis, absorption, elimination, and intracellular digestion.