Digestion Part 1 SBI3U

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Questions and Answers

What is the main difference between mechanical and chemical digestion?

Mechanical digestion involves physical breakdown of food, while chemical digestion involves the breakdown of food using enzymes.

What is the function of the circulatory system in the digestive process?

The circulatory system transports digested nutrients from the digestive system to the cells.

What is an example of a simple animal with a digestive sac?

A jellyfish is an example of a simple animal with a digestive sac.

What are the four main steps of the digestive process?

The four main steps are ingestion, digestion, absorption, and egestion. Signup and view all the answers

What type of digestion occurs in the mouth, stomach, and small intestine?

Chemical digestion occurs in the mouth, stomach, and small intestine. Signup and view all the answers

What is a characteristic of a complete digestive system?

A complete digestive system has two openings, one for intake and one for waste elimination. Signup and view all the answers

What is the primary function of amylase in the digestion process?

Breaking down starch into disaccharides Signup and view all the answers

What is the purpose of mucus in saliva?

Acts as a lubricant to aid in swallowing Signup and view all the answers

What is the term for the process of taking food in and swallowing it?

Ingestion Signup and view all the answers

What type of muscle contractions occur in the esophagus to propel food towards the stomach?

Peristalsis Signup and view all the answers

What is the main function of the stomach in the digestion process?

Mechanical and chemical digestion Signup and view all the answers

What is the maximum capacity of the stomach in terms of volume?

Up to 2L Signup and view all the answers

What is the average length of the gastrointestinal tract in humans, and what factors can influence its length?

The average length of the gastrointestinal tract is approximately 7-9 meters, and its length can vary depending on age and size. Signup and view all the answers

What are the two main types of digestion that occur in the mouth, and what are their roles in breaking down food?

The two main types of digestion that occur in the mouth are physical digestion, which breaks down food into smaller pieces using teeth, and chemical digestion, which breaks down food using enzymes in saliva. Signup and view all the answers

What is the role of the accessory organs in the digestion process, and what are some examples of these organs?

The accessory organs, such as the salivary glands, pancreas, liver, and gall bladder, aid in digestion by producing enzymes and other chemicals that help break down food. Signup and view all the answers

What is the primary function of the enzyme amylase in saliva, and how does it contribute to chemical digestion?

The primary function of amylase is to break down complex carbohydrates, such as starches, into simpler sugars, contributing to chemical digestion in the mouth. Signup and view all the answers

What is the relationship between the type of teeth an animal has and its diet, and how do herbivores and carnivores differ in this regard?

The type of teeth an animal has is directly related to its diet, with herbivores having more molars for grinding and crushing plant material, and carnivores having more canines for tearing and piercing meat. Signup and view all the answers

What are the six main stops in the journey of digestion, and what is the primary function of each stop?

The six main stops in the journey of digestion are: 1) Mouth, 2) Esophagus, 3) Stomach, 4) Small Intestine, 5) Large Intestine, and 6) Rectum and Anus. Each stop has a specific function in the digestion and absorption of nutrients. Signup and view all the answers

Study Notes

Digestion

Digestion is the process of breaking down nutrients and absorbing them into the blood and carrying it to cells.
The digestive system is a group of organs that work together to carry out digestion.
Four main steps: ingestion, digestion, absorption, and egestion.

Mouth

Two types of digestion occur in the mouth: physical and chemical.
Physical digestion: food is broken down into smaller pieces by teeth.
Chemical digestion: breaking food down using chemicals, specifically saliva and acid.
Saliva contains enzymes, which are chemicals that increase the rate of chemical reactions.
The most important enzyme in saliva is amylase.

Saliva

Amylase breaks down starch into disaccharides.
Saliva also dissolves food particles, making it possible to taste food.
It contains mucus, a protective secretion that acts as a lubricant to aid in swallowing.
You produce approximately 0.75 to 1.5 L of saliva each day.

The Bolus

The water in saliva moistens the food and a bolus, or ball of food, is formed from chewing.
The tongue pushes the bolus to the back of the mouth for swallowing.
The bolus is then pushed into the pharynx and a soft palate is raised to prevent food from entering the nasal passages.
At the same time, the larynx is raised against the epiglottis, which covers the entrance to the trachea, preventing the food from entering the lungs.

Esophagus

Food moves from the mouth to the stomach via the esophagus.
Long muscular tube with a 2cm diameter.
The walls stretch because of the food, which activates the smooth muscles, undergoing rhythmic wave-like contractions called peristalsis.
It takes about 8 s for food to travel down the esophagus to the stomach.

Stomach

J-shaped, muscular organ.
Mechanical and chemical digestion.
The stomach can expand and hold up to 2L.

Gastrointestinal Tract

The digestive tract is referred to as the gastrointestinal tract (GI tract).
Approximately 7-9m long, depending on age and size.
Interaction with other systems: circulatory to transport nutrients, nervous and endocrine system regulates digestion.
The GI tract consists of: mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.
The accessory organs are: salivary glands, pancreas, liver, and gall bladder.

Digestive Journey

Digestion is like a journey down a disassembly line with many stops: mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus.
The accessory organs also aid in digestion.

Types of Digestion

Mechanical digestion: occurs in the mouth and stomach, involves tearing, chewing, grinding, and peristalsis.
Chemical digestion: occurs in the mouth, stomach, and small intestine, involves coating food with saliva containing digestive enzymes.

Specialized Digestive Systems

Simple animals have a digestive sac with a single opening into a gastrovascular cavity.
More complex animals digest food along a tract with two openings, one for intake and one for waste elimination.
The human system is a complete digestive system.

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Description

Learn about the process of digestion, the digestive system, and the importance of breaking down nutrients and absorbing them into the blood for cellular function.