"The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder)."
A review of the role of the digestive system in nutrient absorption and metabolism, including the processing of carbohydrates, fats, and proteins and the regulation of energy balance.
Overview of Nutrition and Metabolism: This topic provides an introduction to basic concepts, principles, and processes of nutrition and metabolism.
Chemical Composition of Food: This topic covers the macronutrients (carbohydrates, proteins, and fats) and micronutrients (vitamins and minerals) that make up our food.
Digestion and Absorption: This topic focuses on the mechanical and chemical processes involved in breaking down food into its components and absorbing them into the bloodstream.
Energy Metabolism: This topic covers the biochemical pathways involved in energy production and use within the body, including glycolysis, the Krebs cycle, and oxidative phosphorylation.
Hormonal Regulation of Metabolism: This topic discusses the role of hormones in regulating energy metabolism, including insulin, glucagon, and leptin.
Nutrient Storage and Transport: This topic covers the storage and transportation of nutrients within the body, including the role of liver glycogen, adipose tissue, and lipoprotein particles.
Nutrient Requirements and Dietary Guidelines: This topic discusses the recommended intake of macronutrients, micronutrients, and water, as well as general guidelines for maintaining a healthy diet.
Malnutrition and Nutrient Deficiencies: This topic covers a range of nutritional disorders and deficiencies, including protein-energy malnutrition, vitamin and mineral deficiencies, and eating disorders.
Nutritional Assessment and Counseling: This topic provides an overview of methods used to assess nutritional status and conduct nutritional counseling, including dietary recall, food diaries, and anthropometric measurements.
Nutritional Epidemiology: This topic covers the study of the relationship between diet and health outcomes, including observational studies and randomized controlled trials.
Food Safety and Foodborne Illness: This topic discusses the causes and prevention of foodborne illness, including food handling and preparation practices and food safety regulations.
Nutrition and Disease Prevention: This topic covers the role of nutrition in preventing chronic diseases, including cardiovascular disease, stroke, and cancer.
Special Populations and Nutrition: This topic covers nutrition needs and considerations for special populations, including pregnant and lactating women, infants and young children, and athletes.
Nutrigenomics and Personalized Nutrition: This topic provides an overview of the emerging field of nutrigenomics, which studies the interaction between genes and nutrients, and the potential for personalized nutrition recommendations.
Carbohydrate metabolism: Carbohydrate metabolism refers to the biochemical processes by which carbohydrates are broken down and converted into energy or stored for future use in the body.
Protein metabolism: Protein metabolism refers to the complex set of biochemical processes involved in the synthesis, breakdown, and utilization of proteins in the human body.
Lipid metabolism: Lipid metabolism refers to the biochemical processes involved in the synthesis, breakdown, transport, and storage of fats and cholesterol in the body.
Digestion: Digestion is the process by which food is broken down in the body to release vital nutrients for absorption and energy production.
Absorption: Absorption refers to the process by which nutrients, medications, and other substances are taken up and assimilated by the body, typically occurring in the gastrointestinal tract.
Anabolism: Anabolism refers to the set of metabolic processes that build complex molecules from simpler ones, promoting growth and maintenance within cells and tissues.
Catabolism: Catabolism refers to the process by which complex molecules are broken down into simpler ones, releasing energy in the process.
Glycolysis: Glycolysis is a metabolic pathway that converts glucose into energy in the form of ATP for cellular activities.
TCA cycle: The TCA cycle, also known as the Krebs cycle or citric acid cycle, is a series of chemical reactions that occur in the mitochondria to generate energy by oxidizing glucose, fatty acids, and amino acids, and is a central metabolic pathway in the human body.
Electron transport chain: The electron transport chain is a series of protein complexes and molecules within mitochondria that transfer electrons during aerobic respiration, producing ATP and water.
Oxidative phosphorylation: Oxidative phosphorylation is the process by which cells produce energy in mitochondria through the electron transport chain and ATP synthesis.
Gluconeogenesis: Gluconeogenesis is the metabolic process in which the body synthesizes glucose from non-carbohydrate sources, playing a crucial role in maintaining normal blood glucose levels during fasting or low carbohydrate intake.
Lipogenesis: Lipogenesis refers to the metabolic process by which the body synthesizes and stores fat molecules for energy storage and various physiological functions.
Ketogenesis: Ketogenesis is a metabolic process in which the body produces ketones as an alternative source of energy when carbohydrate availability is limited, such as during ketogenic diets or fasting.
Protein synthesis: Protein synthesis is the biological process by which cells generate proteins, utilizing genetic information encoded in DNA to produce specific protein molecules that are essential for various physiological functions.
Fat synthesis: Fat synthesis refers to the biological process by which the body creates new fatty acids and triglycerides for energy storage.
Vitamin metabolism: Vitamin metabolism involves the processes of absorption, transport, utilization, and excretion of vitamins in the human body.
Mineral metabolism: Mineral metabolism focuses on the absorption, distribution, and utilization of minerals within the human body, and their impact on various physiological processes and overall health.
"Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body."
"The process of digestion has three stages: the cephalic phase, the gastric phase, and the intestinal phase."
"The first stage, the cephalic phase of digestion, begins with secretions from gastric glands in response to the sight and smell of food."
"This stage includes the mechanical breakdown of food by chewing, and the chemical breakdown by digestive enzymes, that takes place in the mouth."
"Saliva contains the digestive enzymes amylase and lingual lipase, secreted by the salivary and serous glands on the tongue."
"Chewing, in which the food is mixed with saliva, begins the mechanical process of digestion."
"This produces a bolus which is swallowed down the esophagus to enter the stomach."
"The second stage, the gastric phase, happens in the stomach. Here the food is further broken down by mixing with gastric acid until it passes into the duodenum, the first part of the small intestine."
"The third stage, the intestinal phase, begins in the duodenum. Here the partially digested food is mixed with a number of enzymes produced by the pancreas."
"Digestion is helped by the chewing of food carried out by the muscles of mastication, the tongue, and the teeth."
"Peristalsis is the rhythmic contraction of muscles that begins in the esophagus and continues along the wall of the stomach and the rest of the gastrointestinal tract. This initially results in the production of chyme which when fully broken down in the small intestine is absorbed as chyle into the lymphatic system."
"Most of the digestion of food takes place in the small intestine."
"Water and some minerals are reabsorbed back into the blood in the colon of the large intestine."
"The waste products of digestion (feces) are defecated from the rectum via the anus."