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16 Cards in this Set
- Front
- Back
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Distinguish among undernourishment, over nourishment, and malnourishment.
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undernourishment- not enough calories (lose weight)
overnoruishment- to many calories(obese) Malnourishment- lacking of essential nutrients |
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Explain the role of leptin in the regulation of fat storage and use.
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A protein hormone when raised it tells your body you're not hungry.
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Define essential nutrients and describe the four classes of essential nutrients.
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A substance that an organism must absorb in preassembled form because it cannot be synthesized from any other material.
1) 8 essential amino acids 2) vitamins co-enzyme 3) minerals 4) essential fatty acids |
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Distingusih between water-soluble and fat-soluble vitamins.
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Fat vitamins store in adipose tissude
water vitamins go right throught you |
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Define and compare the four main stages of food processing.
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Ingestion-eating
digestion- enzyme breakdown of large molecules absorption- uptake of nutrients by cell elemination- passage of undigested materials out of the body in feces |
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Compare intracellular and extracellular digestion.
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In intracellular digestion, food particles are engulfed by endocytosis and digested within food vavules that have fused with lysosomes. In extracellular digestion, enzymatic hydrolysis occurs outside cells in a gastrovascular cavity or alimentary canal.
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Describe the common processes and structural components of the mammalian digestive system
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After food is chewed and swallowed, it takes 10-15 seconds for it to pass down the esophagus and into the stomach, where it spends 2-6 hours being partially digested. final digestion and nutrient absorption occur in the small intestine over a period of 5-6 hours. in 12-24 hours, any undigested material passes through the large intestine, and feces are expelled through anus.
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Name three function of saliva
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moistens the food
Amylase enzyme hydrolyzes starch and glycogen into smaller polysaccharides and the disaccharide maltose. Buffer that neutrilizes acid to prevent tooth decay and antibacterial agent. |
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Where and how is carbohydrates digested and absorbed
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carbohydrates digestion starts in the mouth by saliva. When these carbohydrates enter the small intestine then amylase is secreted by the pancreas into the duodenum. Absorbed in the small intestine
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Where and how is proteins digested and absorbed
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Digestion starts in stomach by breaking down proteins by pepsin into small polypeptides. then in the lumen of the small intestine the polypeptides are broken down by pancreatic trypsin and chymotrypsin(these protein digesting enzymes, or proteases cleave bonds adjacent to certain amindo acids) into smaller polypeptides then pancreatic carboxypeptidase breaks them into amino acids. then absorebed in the jejunum and ileum
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Where and how is fats digested and absorbed
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Fat taken in the diet is digested in the Small Intestine with the aid of Bile acids and salts which act as emulsifiers and break down the larger fat droplets into smaller ones. These are then acted upon by "lipases" which are secreted in the intestinal digestive. juices. Ultimately the fats are converted into Fatty acids and Glycerol. These are then absorbed in the form of "chylomicrons (small packages of fat and protein)" into the lymphatic channels via the lacteals and poured into the blood.
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Explain why pepsin does not digest the stomach lining.
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Pepsin is stored as pepsinogen where it is inactive. stomach lining protects itself from self-digestion by secreting mucus
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Explain how small intestine is specialized for digestion and absorption.
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The duodenum is the site where chyme from the stomach mixes with digestive juices from the pancreas, liver, and gallbladder.The second portion of the small intestine is the jejunum. It is composed of many folds that increase the surface area for absorption, known as the brush border membrane. The third portion of the small intestine is the ileum. It is responsible for the very selective absorption of some significant nutrients, including vitamin B-12 and vitamin C.
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Describe the major functions of the large intestine
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The cecum is important for fermenting ingested material. The appendix, small role in immunity. A major function of the colon is to recover water that has entered the alimentary canal as the solvent of digestive juices.
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Relate variations in dentition and length of length of the digestive system to the feeding strategies and diets of herbivores, carnivores, and omnivores.
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Carnivore has pointed incisors and canines with jagged premolars and molars.Shorter alimentary canal. larger stomachs.
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Describe the roles of symbitotic microorganisms in vertebrate digestion.
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Symbiotic microorganisms help herbivores digest plants by breaking down cellulose.
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