Science Test 16: Section 1

What happens in the large intestine?

As chyme enters the large intestine, it's still a thin, water mixture. The alrge intestine absorbs water from the undigested materials. This helps maintain homeostasis. After the extra wawter is absorbed, the remaining undigested materials become more solid. Muscles in the rectum and anus control the release of the feces, or semisolid wastes, from the body.

When does digestion begin?

As soon as food enters your mouth.

What is the function of the mouth in chemical digestion?

Chemical digestion begins in mouth when saliva is added to the chewed food in your mouth.

What does the pancreas make?

Chemical digestion of carbs, proteins, and fats occur when a digestive solution from the pancreas is mixed in to the chyme, etc. This solution reduces the effect of the hydrochloric acid solution. Your pancreas also makes insulin, a hormone that allows glucose, a sugar, to pass from the bloodstream into your cells.

Absorption

Absorption of broken down food takes place in the small intestine. The wall of the smal intestine has many ridges and golds. They're covered with fingerlike projections called villi. Villi add more surface area for nutrients to be absorbed in the small intestine. Nutrients move into blood vessels within the villi. Then, blood moves the nutrients to all cells of your body. Peristalsis slowly forces the remaining undigested and unabsorbed materials into the large intestine.

How does chemical digestion take place?

Chemical digestion takes place when chemical reactions break down food.

The role of the stomach in chemical digestion.

Chemically, food is mixed with enzymes and strong digestive solutions, such as hydrochloric acid solution, to help break it down.

What do enzymes help you do?

Enzymes help you digest carbs, proteins, and fats.

The role of the stomach in mechanical digestion.

The stomach, a muscular bag's role in mechanical digestion is that food is mixed in the stomach by peristalsis.

What are the accessory organs?

The tongue, teeth, salivary glands, liver, gallbladder, and pancreas. These are important in both chemical and mechanical difestion even though food doesn't pass through them.

What does the esophagus do?

When food moves into esophagus, it passes over a flap of tissue called the epiglottis. This covers the opening to the windpipe to prevent food from entering it. No digestion takes place in the esophagus. Smooth muscles in the wall of the esophagus move food downward with a squeezing action. These waves of muscle contraction, called peristalsis, move food through the entire digestive tract.

How is salive produced and what does it contain?

Saliva is produced by salivary glands. It contains water, mucus and an enzyme. Food mixed with saliva is moved to the back of the mouth by the tongue, swallowed, and passed into the esophagus.

Bacteria

Some bacteria live in may of the organs of the digestive tract including your mouth and large intestine. Some of them live in a relationship that helps both of us. The bacteria in your large intestine food on undigested material and make vitamin K and two B vitamins. Vitamin K is needed for blood clotting, and the two B, niacin and thiamine, are important for the nervous system. The breakdown of intestinal materials by bacteria produces gas.

Chyme

Special cells in the walls of the stomach release about two liters of hyfdrochloric acid solution each day. This solution works with the anzyme pepsin to digest protein and destroy bacteria in food. The stomach also produces mucus. Mucus makes food more slopery, and it protects the stomach from the strong, digestive solutions. Food is changed in the stomach into a thin, watery liquid called chyme. Chyme slowly moves into the small intestine.

What are nutrients?

Substances in food that provide energy and materials for cell development, growth and repair.

What are the two parts of the digestive system?

The digestive tract, and the accessory organs.

How are nutrients absorbed and moved into the blood?

Food is broken down and absorbed into the blood. from there, nutrients are transported to cells. Unused substances are eliminated as wastes.

Where are enzymes produced?

In the salivary glands, stomach, small intestine, and pancreas.

What are the 4 stages of food being processed?

Ingestion, Digestion, Absorption, and Elimination.

What is the function of the mouth in mechanical digestion?

It begins in the mouth when you chew your food with your teeth and mix it with your tongue.

Where does chyme go after it leaves the stomach?

It enters the first part of the small intestine, called the duodenum. Most digestion takes place there. Bile, a green fluid from the liver, is added to chyme there. The acidic solution from the stomach makes large fat particales float to the top of the chyme. Bile breaks up the fat particles, the same way detergent breaks up grease.

How does mechanical digestion occur?

Mechanical digestion occurs when food is chewed, mixed and churned.

What are enzymes?

Needed for chemical digestion to take place, enzymes are types of protein that speed up the rate of a chemical reaction in your body.

What are the major organs of the digestive tract?

The mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus. Food passes through all these organs.

What does digestion do?

breaks down food so that nutrients can be absorbed and moved into the blood.