BSC2010 BIOLOGICAL SCIENCE 1 FALL 2012 STUDY GUIDE 18 THE DIGESTIVE SYSTEM Vocabulary Amylase enzyme in saliva hydrolyzes starch and glycogen into smaller polysaccharides and disaccharide maltose Alimentary canal two openings see complete digestive tract Absorption Third stage of food processing cells take up small molecules such as amino acids and simple sugars Antibacterial agents i e lysozyme protects us from bacterial infection attacks protective walls of bacteria Appendix a finger like extension of the human cecum has a minor and dispensable role in immunity Bolus tongue manipulates food into a ball Bile mixture of substances that is made in the liver and digests fats and other lipids in the small intestine Cofactor non protein chemical compound that is bound to a protein and is required for the protein s biological activity Complete digestive track Digestive tube extending between two openings a mouth and an anus Chyme a mixture of ingested food and digestive gastric juice Chemical digestion It s the chemical breakdown of food into simpler compounds Proteins are broken down to amino acids carbohydrates are broken down to simple sugars and fats are broken down to fatty acids and glycerol Cecum ferments ingested material especially in animals that eat large amounts of plant material Chief cells release pepsin into lumen in an inactive form called pepsinogen Digestive system system of organs for acquiring and processing foods Digestion second stage of food processing food is broken down into molecules small enough for the body to absorb Essential amino acids the remaining amino acids that can t be synthesized and must be obtained from food Elimination last step undigested material passes out of digestive system Esophagus connects to the stomach Epiglottis The epiglottis is flap of cartilage located in the throat behind the tongue and in front of the larynx Gastric glands any of the branched tubules in the inner lining of the stomach that secrete gastric juice and protective mucus Gall bladder where bile is stored Ingestion First stage of food processing the act of eating Liver makes bile for emulsifying lipids detox and destroys defective red blood cells Lymph vessel a vascular duct that carries lymph which is eventually added to the venous blood circulation Large intestine colon where alimentary canal ends includes colon cecum and rectum Minerals inorganic nutrients such as zinc and potassium that is usually required in small amounts Mechanical digestion takes place in mouth teeth chew food Mucin any of a class of glycoproteins found in saliva gastric juice etc that form viscous solutions and act as lubricants or protectants on external and internal surfaces of the body Mucus cells Any of the specialized epithelial cells found in the mucous membrane of the stomach intestines and respiratory passages that secrete mucus Microvilli brush border microscopic appendages on each epithelial cell of a villus Nucleases an enzyme capable of cleaving the phosphodiester bonds between the nucleotide subunits of nucleic acids Nutrient absorption occurs mostly in small intestine Pancreas aids in chemical digestion by producing an alkaline solution rich in bicarbonate as well as several enzymes Proteases protein digesting enzymes Pepsin a protease works best in acidic environments By breaking polypeptides it cleaves proteins into smaller polypeptides Parietal cells secrete hydrogen and chloride ions which form HCL Peristalsis alternating waves of contraction and relaxation in the smooth muscles lining the canal Pepsinogen chief cells release pepsin into the lumen in this inactive form Pharynx throat region opens the esophagus and trachea Rectum the lower part of your large intestine where your body stores stool Saliva a watery substance located in the mouths of organisms secreted by the salivary glands Salivary glands presence of food stimulates a nervous reflex that causes salivary glands to deliver saliva through ducts to the oral cavity Stomach located just below the diaphragm in the upper abdominal cavity Stores food and continues digestion some nutrient absorption Sphincter Act like drawstrings to close off alimentary canal they regulate the passage of material between compartments Small intestine where most enzymatic hydrolysis of macromolecules from food occur over 6 m long Trachea connects to the lungs Vitamins organic molecules with diverse functions that are required in the diet in very small amounts Villi finger like projections in the large folds of the lining in small intestine Principles and Concepts Know the components of a healthy nutritional diet o Source of chemical energy o Building blocks to make complex organic compounds o Other essential nutrients and materials that we cannot synthesize on our own Know what the essential amino acids are and their food sources Fig 41 2 8th ed Essential amino acids for adults Beans and other legumes Methionine Valine Threonine Phenylalanine Leucine Leucine Isoleucine Tryptophan Lysine Corn maize and other grains I mportance of well balanced diets Proteins we eat are not used as proteins but as sources of amino acids and energy Know what we do with the proteins we eat o They are used as sources of amino acids and energy Know the definition of a vitamin Know the major functions of the vitamins in our diet o Vitamins Organic Compounds we need but cannot synthesize on our own Know some of the minerals needed by the body their major functions and symptoms if there is deficiency or excess of minerals Know the four stages involved in the processing of food by the digestive system and what organs and parts of the body are involved in each o Ingestion Mouth o Digestion o Absorption o Elimination Know that humans have a complete digestive track called the alimentary canal and know its component organs and parts Know that ingestion occurs through the mouth and how digestion begins in the mouth and the roles played by the teeth and salivary glands during digestion Know the pathway that food follows as it passes from the mouth to the stomach o Teeth mechanical digestion o Salivary Glands release saliva o Saliva amylase mucin buffers antibacterial agents such as lysozyme o Mouth Bolus partially digestion food Pharynx Esophagus Stomach Know the two passageways that stem from the pharynx trachea and esophagus Know where these passageways go and know the part of the body that is the gatekeeper to these passageways Fig 41 10 o Pharynx Trachea Lungs o
View Full Document
Unlocking...