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35 Cards in this Set
- Front
- Back
What are nutrients? What 5 categories do they fit into?
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Nutrients: substances that must be supplied in the diet.
lipids, carbohydrates, proteins, minerals, vitamins |
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What are the primary sources of energy?
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Carbs and Fats
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Describe 3 types of lipids.
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1. fat/triglycerides: source of energy
2. phospholipids: make up cell membranes 3. cholesterol: makes up sex hormones and bile. |
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What are essential fatty acids? What are essential amino acids?
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Must acquire lipids/amino acids from the diet because are not synthesized naturally in the body
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What is the quickest source of energy? How is this source stored in humans?
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Carbohydrates, including sugars and starches!
Stored in form of glycogen: a polysaccharide that is a chain of glucose molecules |
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define urea
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the waste product of protein breakdown, which is filtered from the blood by the kidneys
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List some functions of proteins.
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- composed of amino acids that help make hormones, other amino acids, and new proteins
- act as enzymes - antibodies - muscle proteins |
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Describe what occurs during a protein deficiency.
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protein deficiencies can result in a lot of scary conditions, like kwashiorkor. muscles are wasted due to a lack of protein.
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define minerals and describe iron.
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include various elements and inorganic molecules that must be obtained through the diet.
Iron: produces hemoglobin... a lack of can lead to anemia |
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define vitamins.
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group of organic compounds that must be obtained through diet
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Vitamin C (water soluble vitamins?)
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is an antioxidant. It combines with free radicals that would usually damage DNA to limit their effects. (can cause scruvy)
is water soluble, which means.. - dissolves in blood plasma - not much is stored in body - works with enzymes |
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Vitamin D (fat soluble vitamin?)
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promotes bone growth and increases calcium absorption. (can cause rickets)
is fat soluble which means... - can be stored in fat and can accumulate over time |
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Vitamin K (fat soluble?)
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regulates blood clotting.
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Digestion systems must accomplish....
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ingestion, mechanical breakdown, chemical breakdown, absorption, elimination
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Define intracellular digestion (sponges)
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: digestion occurs within individual cells
1. once food is englufed, food is enclosed in a food vacuole. 2. food vacuole fuses with digestive enzymes called lysosomes. 3. food is broken down |
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define extracellular digestion
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larger, more complex organisms evolved a chamber where food could be broken down by enzymes OUTSIDE of the cells
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Describe the gastovascular cavity in Hydras. Why is this still a very simple digestive system?
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: digestive sac with a SINGLE OPENING, therefore both food is ingested and waste is ejected here
Because of the single opening, simple sac digestive systems can only process one meal at a time |
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describe the tubular digestive system in earthworms.
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- mouth
- pharynx (connects mouth to esophagus) - esophagus - crop - storage organ tht collects food - gizzard- where food is ground - intestine - enzymes break down - anus |
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What are ruminant animals?
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Have a special digestive system in order to break down the cellulose in the food that they eat
(microorganisms produce cellulase) - herbivore intest. are longer because need more time for absorption |
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The Mouth: SALIVARY GLANDS
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- mechanical breakdown begins with the teeth
- 3 salivary glands pour out saliva, which contains amylase (breaks down starches into dissaccharides) -lubricates food, carries bacteria killing enzyme to fight infection |
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The Mouth: TOUNGE, PHARYNX
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- tongue pushes food into the pharynx, which connects to the esophagus
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(LARYNX, EPIGLOTTIS)
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- larynx: connects nose/mouth to trachea
epiglottis: flap of tissue that blocks of respiratory passages so food is directed into esophagus, not trachea. |
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The Esophagus
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- Swallowing forces food into a muscular tube called the esophagus
- The esophagus forms waves of muscular contraction (peristalsis) that carry food to the stomach |
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The Stomach and Pyloric Sphincter
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stomach: expandable muscular sac
pyloric: ring of muscle that separates the stomach from the small intestine; also regulates the passage of the food into small intest |
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What are the stomach's 3 major functions?
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1. store food; release to small intestine
2. mechanical breakdown: muscular walls contract and churn food 3. chemical breakdown: there are glands in stomach that secrete enzymes and hormones and such |
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What are the stomach's secretions?
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- gastrin: (hormone) stimulates the production of hydrochloric acid
- HCI: makes fluid in stomach acidic, allows pepsin to activate - pepsin (a type of protease): breaks proteins into shorter chains - mucus: protects stomach wall from acid |
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define chyme
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: mix partially digested food particles + stomach secretions.
- highly acidic - goes through the pyloric sphincter and into the small inestine |
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The Small Intestine: LIVER AND GALLBLADDER
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- stores fats and carbs (in glycogen) for energy, regulates blood glucose levels, stores iron, detoxifies harmful
- produces BILE, stored in gallbladder |
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define bile
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: mixture of bile salts, water, other salts, cholesterol
- bile salts breaks down fat in the chyme by dispersing them into small particles that enzymes (lipases) can act on |
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The Small Intestine: PANCREAS
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- secretes pancreatic juice
- made up of water, sodium bicarbonate (buffer: neutralizes the acidic chyme), and digestive enzymesssss such as *amylase, lipase, protease |
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The Small Intestine: Absorption
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most absorption occurs in the small intestine.
- fingerlike projections, VILLI and stemming from that MICROVILLI, create more surface area - fats = absorbed by lacteal on each villus - water, monosaccharides, amino acids, vitamins, minerals.... absorbed by small intestine |
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define segmentation movements
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: contractions in the small intestine that slosh chyme back and forth
- brings nutrients into the surface of the intestine where they can easily be absorbed |
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The Large Intestine
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colon: most of length
rectum: terminal end A mix of water, undigested nutrients, and fiber enters the large intestine - contains bacteria that consume the unabsorbed nutrients |
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The Large Intestine: FECES
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: semi solid remnants that consist of indigestible wastes and dead bodies of bacteria
- peristalsis moves the feces out |
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How does the nervous system impact the digestive system?
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1. sceretion of saliva
2. secretion of HCI and gastrin 3. acid secretion is regulated by negative feedback |