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Ch. 15 Science
3rd 9 wk.- Ch. 15 Science-Haggard 7th gr (also study daily assignments #9)
Question | Answer |
---|---|
The six nutrients necessary for human health are: | carbohydrates, fats, proteins, vitamins, minerals, and water |
Describe proteins. | made of long chains of amino acids |
What is the most important nutrient and why. | Water, it is needed for all body processes |
What is a "calorie"? | the amount of ENERGY needed to raise the temperature of 1 gram of water by one celsius degree. |
What is a "Calorie"? | used to measure the energy content of food, 1,000 calories; the energy our body needs comes from the food we eat |
What are the 3 functions of the digestive system? | breaks down food into molecules the body can use, the molecules are absorbed into the blood and carried throughout the body, wastes are eliminated from the body |
How long is the digestive system from beginning to end? | about 9 meters |
Define digestion. | the process by which your body breaks down food into small nutrient molecules. |
Name the two kids of digestion. | mechanical, chemical |
Explain mechanical digestion. | foods are physically broken down into smaller pieces, occurs when you bite into a sandwich and chew it into small pieces. |
Explain chemical digestion. | chemicals produced by the body break foods into their smaller chemical building blocks, ex. the starch in bread is broken down into individual sugar molecules. begins in the mouth with the enzyme saliva |
Define absorption. | the process by which nutrient molecules pass through the wall of your digestive system into your blood--materials that are not absorbed are eliminated from the body as wastes. |
Where do both mechanical and chemical digestion begin? | the mouth |
What are enzymes? | proteins that speed up chemical reactions in the body |
How is food prevented from entering the windpipe? | as you swallow, a flap of tissue, called the epiglottis, seals off the windpipe, preventing the food from entering |
What is the esophagus? | a muscular tube that connects the mouth to the stomach |
What is mucus? | a thick, slippery substance produced by the body; makes the food easier to swallow and move along, it lines the esophagus |
What is peristalsis? | involuntary waves of muscle contraction that keep food moving in one direction; occurs in the stomach |
Describe the stomach. | a J-shaped, muscular pouch located in the abdomen--As you eat, it expands to hold all of the food that you swallow. |
Where does MOST mechanical digestion occur? | stomach, some chemical digestion occurs there, too. |
What enzyme is found in digestive juice? | pepsin |
Explain the role of pepsin during chemical digestion. | it chemically digests the proteins in your food; breaking them down into short chains of amino acids |
Why doesn't stomach acid burn a hole in your stomach? | cells in the stomach lining produce a thick coating of mucus, which protects the lining |
When the thick liquid leaves the stomach, where does it go? | enters the small intestines |
Where does MOST chemical digestion and absorption take place? | small intestines |
Describe the small intestines (length and diameter). | about 6 meters long; makes up 2/3 of the length of the digestive system; small diameter (from 2/3 cm wide) |
What is the largest organ INSIDE the body? | liver |
What is the role of the liver in the digestive system? | produce bile |
What is bile? | substance that breaks up fat particles; flows from the liver into the gallbladder and then into the small intestines. |
What is the gallbladder? | organ that stores bile |
What is the pancreas? | triangular organ that lies between the stomach and the first part of the small intestines; produces enzymes that flow into the small intestine and helps break down starches, proteins, and fats |
What is villi? | tiny finger-shaped structures that cover the surface of the small intestine; absorb nutrient molecules |
How do nutrients from the small intestine get to the rest of the body? | they pass from the cells on the villi into blood vessels. The blood carries the nutrients throughout the body for use by body cells. |
Describe the large intestine. | the last section of the digestive system; about 1.5 metes long; runs up the right-hand side of the abdomen, across the upper abdomen, and then down the left-hand side |
Explain how bacteria found in the large intestine can be helpful. | they make certain vitamins, including vitamin-k needed for blood clotting |
What happens to water as the remaining material moves through the large intestine? | it is absorbed into the bloodstream |
Define rectum. | short tube at the end of the large intestine |
Where is waste material eliminated from the body? | through the anus, a muscular opening at the end of the rectum |
What is Vitamin K needed for? | blood clotting |
What is a good source of Vitamin K? | leafy vegetables |
STUDY DAILY ASSIGNMENT #10---THE DIGESTIVE SYSTEM | Be able to identify and label the parts of the digestive system |