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32 Cards in this Set
- Front
- Back
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What is the job of the digestive system?
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Performs digestion of food, absorption of nutrient and removes solid waste
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Taster/Supertaster
benefit |
highly sensitive to bitter, sweet, fat & salty
- (+) may need less sugar & salt to be satisfied |
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Non-taster
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do not notice flavors as readily
- (+) don't pick up bitterness in some green |
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Four principles about the digestive system
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1. The human body is made from the nutrients obtained from foods
2. Nutrients in foods are not used directly 3. Our body only uses the nutrients it needs 4. Other body systems are an integral part of the functioning of the digestive system |
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Digestion
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Nutrients are broken down into absorbable units
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Absoprtion
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Absorbable units are taken up by the small intestinal cells for transport by the blood or lymph
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How our body only uses amount of nutrient that it need
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-immediately USES nutrients for energy and to build body components
-STORES what it doesn't need immediately -ELIMINATES what it can't use |
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What is the digestive tract?
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Flexible muscular tube extending from the mouth to the anus
20-30 ft long |
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The 7 Organs that food passes through during digestion
and what is does there |
1. Mouth (Ingestion and digestion)
2. Esophagus (Ingestion) 3. Stomach (Digestion) 4. Small Intestine (Digestion and Absorption) 5. Large Intestine (Absorption and Elimination) 6. Rectum (Elimination_ 7. Anus Elimination) |
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What do organs produce/secrete?
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Enzymes, digestive juices and emulsifiers that aid in digestion
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What types of digestion are there that the digestive tract uses?
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Mechanical and Chemical
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What is Mechanical digestion?
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Physical breakdown of food into smaller pieces
-chewing, churning |
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What is Chemical Digestion?
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Breakdown of food into component parts
-Juices and enzymes interact -Digestive juices, enzymes, emulsifiers |
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How does food move through the digestive tract (2)?
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Peristalsis and Segmentation
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Peristalsis VS Segmentation
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PERISTALSIS- coordinated muscular contractions that move food along the digestive tract
SEGMENTATION- periodic squeezing of the intestine by its circular muscles; breaks down chyme |
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Enzymes
and examples |
molecules that speed up chemical reactions, "catalysts"
-Amylases- break down starch -Proteases- break down proteins -Lpases- break down fat |
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Digestive Juices examples
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-Gastric juice
-Pancreatic juice |
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Ex of an emulsifier
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Ex Bile
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What is the job of the esophageal sphincter?
Consequences? |
prevents acidic environment from stomach from reaching esophagus
-could results in heart burn or ulcer |
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What protects the stomach from the acidity?
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Mucosa layer
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What is the job of the pyloric valve?
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controls the flow of chyme into the small intestine
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What acidity can the stomach get down to?
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2 ex. lemon juice, gastric juice
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What are the parts of the small intestine and how long are they?
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1. Duodenum 10-12 inches long
2. Jejunum- 8-12 ft 3. Ileum 6.5-12 ft |
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How long in the small intestine?
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7- 8 hours
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Why doesn't fiber get absorbed in the body?
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Doesn't have enzymes to break it down
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What are the mechanisms of absorption (3)?
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1. Simple diffusion
2. Facilitated diffusion 3. Active Transport |
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What is simple diffusion?
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Some nutrients (such as water and small lipids) are absorbed my simple diffusion. They cross into intestinal cells freely.
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What is facilitated diffusion?
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Some nutrients (such as water-soluble vitamins) are absorbed by facilitated diffusion. They need a specific carrier to transport them from 1 side of the cell membrane to the other. Alternatively, facilitated diffusion may occur when the carrier changes the cell membrane in such a way that the nutrients can pass through)
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What is active transport?
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Some nutrients (such as glucose and amino acids) must be absorbed actively. These nutrients move against a concentration gradient, which requires energy (ATP)
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How long in the large intestine?
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12-14 hours
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What goes on in the large intestine?
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-Waste movement
-Bacterial digestion of fiber (soluble ones) -Nutrient absorption (Waters and minerals) |
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What occurs in the rectum and anus?
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Waste movement
Sphincter to anus Waste elimination |
