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38 Cards in this Set
- Front
- Back
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The goal of carbohydrate digestion
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Breakdown of large, complex molecules into small, absorbable monosaccharides.
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What is amylose and amylopectin's role in the mouth
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Salivary glands release salivary alpha-amylase which hydrolyzes alpha -1, 4 glycosidic bonds in amylose/amylopectin, forming dextrins.
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Digestion of amylose in the small intestine
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The pancreas releases pancreatic alpha-amylase into the small intestine which hydrolyzes alpha-1 4 glycosidic bonds. Dextrins are broken into maltose.
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Digestion of amylopectin in the small intestine
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The pnacreas releases pancreatic alpha-amylase into the small intestine which hydrolyzes alpha-1, 4 glycosidic bonds. Dextrins are broken down into maltose and limit dextrins.
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Digestion of amylose on the brush border of the small intestine
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Maltose is hydrolyzed by maltase, a brush border enzyme, forming free glucose.
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Digestion of amylopectin on the brush border of the small intestine
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maltose us hydrolyzed by maltase, a forming free glucose. The alpha-1, 6 glycosidic bonds in limit dextrins are hydrolyzed by <alpha- dextrinase, froming glucose
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Describe how glucose and galactose are transported in the brush border
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transported into enterocytes via atp active transport mechanisms. Glucose moves from lower o higher concentration and requires Na (NA dependent)
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Describe how fructose is transported in the brush border
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transported via enteroctes via facilitated diffusion; moves from higher to lower concentration.
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Where does the hepatic portal vein transport absorbed nutrients
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The liver
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Why does carbohydrate digestion stop while food is in the stomach?
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Salivary enzymes lose their ability to continue digestion in an acidic environment.
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After fructose and galactose are converted to what in the liver?
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Glucose
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Liver decides how much glucose to
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store as glycogen
convert to fat release into the blood |
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What is fiber's role?
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Fiber is required to regulate passage through the GI tract and slow glucose absorption. Fiber provides little, if any energy
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What is and happens with Lactose intolerance
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Its the inability to digest lactose due to insufficient production of lactase. Lactose enters the large intestine undigested and causes abdominal cramping, bloating, flatulence, and diarrhea.
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Lactose intolerance has a high incidence in what populations?
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Asian Americans, Native Americans, and African Americans
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Describe Glycogenolysis
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glucose stored in livers as glycogen and when blood glucose goes down the liver will release glycogen and it then undergoes hydrolysis resulting in single molecules of glucose released into the blood.
The liver is stimulated by glucagon |
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Is skeletal muscle sensitive to glucagon or epinephrine?
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Glucagon insensitive
epinephrine sensitive |
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What are ketone bodies?
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Fat fragments usually combined with a compound derived from glucose (or protein) before being used for energy and thus without this compound from glucose, fat fragments combine with each other producing acidic Ketone bodies.
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What is gluconeogensis?
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Glucose being made from protein and its a very expensive way to make glucose.
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Define ketosis
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the accumulation of ketone bodies in the blood. Leads to abnormal acid-base balance
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What is the normal blood glucose level?
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70-110 mg/dl
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What is insulin?
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Hormone secreted by the pancreas in response to increased blood glucose concentration. Moves the glucose from the blood into the cells.
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What is glucagon?
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Hormone secreted by the pancreas in response to low blood glucose concentration. Stimulates the liver to release glycogen stores to release glucose.
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What does epinephrine do?
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Released during stress and releases glucose from liver glycogen to produce immediate energy
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Describe what the beta and alpha cells produce in the inslets of langerhana?
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Beta cells-- produce hormone insulin in response to increased blood glucoes.
Alpha-cells--produce hormone glucagon in response to decrease blood glucose |
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Describe type I diabetes
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Less common
Pancreas fails to make insulin AKA: Insulin dependent diabetes mellitus Juvenile diabetes |
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Describe type II diabetes
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More common
Obesity is major factor AKA: Non insulin dependent-diabetes mellitus Adult onset |
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When does hyperglycemia occur?
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When cells are not bale to readily take up glucose.
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Insulin promotes energy storage and is thus an ANABOLIC hormone. Please give more information in what this means
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Insulin promotes storage of excess glucose in forms of glycogen and fat.
Stimulates protein synthesis--which inhibits breakdown of muscle. Glycogensis--formation of glycogen controlled by action of insulin in liver and skeletal muscles. Excess glucose up-taken by adipose tissue--irreversible metabolic transformation. |
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In the fight or flight response the adrenal gland releases cortisol and epinephrine. Describe what it does to the blood glucose levels
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Cortisol: increases blood glucose via gluconeogenesis and glycogenolysis
Epinephrine: Increases blood glucose through glycogenolysis |
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What are two important factors to remember about the glycemic index?
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1. measure based on the extent to which food containing 50g carbohydrates increases blood glucose concentrations.
2. Lower glycemic foods speculated with lower risk of developing type 2 diabetes. |
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List the Dietary Reference intakes for Carbohydrates
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AMDR: 45-65% of totoal energy from carbs
RDA: 130g/day AI: 20-38g/day No UL Added sugars less than 25% of total kcal |
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Describe the characteristics of monosaccharides
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simple sugars, hexoses, 6 C 12 H 6 O,
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Describe disaccharides
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2 monosaccharides bonded together, lactose, sucrose, maltose, contain glycosidic bond
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Describe glucose
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emd product of digestion which is absorbed into the blood for distribution to cells/tissues, known as blood sugar--normal fasting blood glucose: 70-110mg/dL
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Describe galactose
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Rarely occurs naturally as a single sugar, monosaccharide in milk, component of glycolipids and glycoproteins, converted to glucose used for energy
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Describe Fructose
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Sweetest of the sugars, found naturally in fruits, honey, and sap; used to sweeten products such as cereal, desserts in the form of high-fructose corn syrup
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How does a glycosidic bond form?
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CONDENSATION REACTION:
a hydroxyl group from one mono combine with a hydrogen atom from another mono to create a new molecule |
