IUB BIOL-L 112 - Components of the Human Digestive System (2 pages)

Unformatted text preview:

BIOL L 112 1nd Edition Lecture 4 Outline of Last Lecture I Nutrition II Essential Nutrients A Essential Amino Acids B Essential Fatty Acids C Essential Vitamins D Essential Minerals III Malnutrition A Undernutrition B Essential Nutrients Deficiencies IV Introduction to the Four Stages of Food Processing Outline of Current Lecture I The Oral Cavity s Role in the Human Digestive System II The Stomach s Role in the Human Digestive System III The Small Intestine s Role in the Human Digestive System A Enzymes in the Pancreas Current Lecture I The oral cavity in the mouth is where chemical and mechanical digestion of food begins Chewing food signals a nervous reflex with signals the salivary glands to release saliva This saliva contains mucus a mixture of water salts cells and mucins buffers help to neutralize acids and protect teeth and antibacterial agents called lysozymes Located in the oral cavity the tongue processes ingested material for swallowing It helps shape a bolus or a ball of chewed food When the bolus reaches the throat a swallowing reflex is triggered and the epiglottis moves down to prevent food from entering the trachea The bolus then enters the esophagus Peristalsis then moves the bolus towards the stomach II Within the stomach four major cells are in the lining that makes up the gastric glands First mucus cells recreate mucus that lubricates and protects the stomach cells Chief cells secrete the protein pepsinogen Pepsin is an enzyme that functions to digest peptide bonds and attacks proteins which break into polypeptides Lastly parietal cells secrete HCl which functions to kill bacteria denature proteins to lose their tertiary These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute structure and activate pepsinogen to pepsin In the stomach ulcers can occur from bacteria but may be treated with antibiotics III Most of the chemical digestion processes take