3-Energy Balance and Diabetes Flashcards
What is the basic energy dilemma?
Food intake is intermittent. Glucose requirement, especially for the nervous system is continuous. Therefore the body must have a way to store and to mobilize blood glucose at a constant level. Your cells need energy all the time, but your not taking in energy all the time. The basic energy dilemma is that energy cannot be created nor destroyed, but it has to be stored and metabolized continuously.
What is gluconeogensis?
Glycogen stores can be used up after a few hours of fasting. New glucose molecules can be synthesized from proteins and fat the process of gluconeogenesis. Carried out by liver it has enzymes to run glycolysis in reverse.
What can biomolecules be used for?
Biomolecules can be broken down to release energy, used to synthesize other molecules, and converted to energy storage molecules including glycogen (carbohydrate)and triglyceride (fat).
What is the metabolic rate?
The metabolic rate is the amount of energy (heat + work) released per unit time. Influenced by muscular activity, age, gender, body surface area, environmental temperature. Nutrient molecules are sugar. Gets broken down and energy gets releases as ATP and heat, When ATP gets broken down in order to do wok, heat also gets produced. All of this is divided by a certain unit of time and this is the metabolic rate.
What kind of work is used to calculate the metabolic rate?
Mechanical, chemical, and transport.
What is mechanical work?
Mechanical work is the use of proteins to generate movement (muscles, cilia). This is why you metabolic rate increases as you gain more muscles.
What chemical work?
Chemical work is the formation of chemical bonds (anabolism).
What is transport work?
Transport work is moving molecules across
membranes (active transport endo/exocytosis).
What is basal metabolic rate (BMR)?
Metabolic rate of person who is awake, lying down, physically/mentally relaxed, and fasted for 12 hours. Roughly equal to rate of oxygen consumption.
What is energy balance?
Energy stored is equal to energy input minus energy output. Energy output is equal to work performed + heat released. A positive energy balance exist when the energy input is greater than energy output. Negative energy balance exist when energy input is less than energy output. Generally, body is not in energy balance. The Absorptive State is 3-4 hours following meal, a positive energy balance and energy stored. The Postabsorptive is between meals, a negative energy balance and energy is mobilized. Glucose sparing happens because most cells metabolize proteins and fat, saving glucose for the nervous system.
What are Adipocytes/Adipose Tissues?
Adipocytes/Adipose Tissues are cells that store fat (triglycerides). 20-30% body weight is normal. Can be up to 80% body weight. 75-80% total energy reserves. Contains enough energy to last approxiamately 2 months. Transitions between post-absorptive and absorptive states regulated by hormones and endocrine system primarily by: Insulin, Glucagon, Epinephrine.
What is the purpose of insulin?
Insulin promotes synthesis of energy storage molecules. Insulin is anabolic hormone which builds things and induces storage. Increased release during absorptive state (blood glucose levels high). Decreased release during post-absorptive state (blood glucose levels low). Produced by beta cells in islets of Langerhans in pancreas. When you release insulin the body says too much sugar in the blood which causes uptake of sugar in the cells. Blood is in your capillaries, blood sugar and cellular sugar is different. High blood sugar means low cellular sugar and high cellular sugar means low blood sugar.
What does insulin do all over the body?
Insulin is released by the pancreas. In most tissues glucose is taken in except by the brain, liver, and exercising muscles. It increases glucose uptake, amino acid uptake, and protein synthesis in most tissues. Increases fatty acid and triglyceride synthesis in adipose tissues and the liver, and glycogen synthesis in the liver and mucsles. It decreases protein breakdown in most tissues. Decreases lipolysis in adipose tissues, decreases glycogenolysis in the liver and muscles, and decreases gluconeogenesis in the liver.
What happens during glucose uptake?
Glucose transport protein 4 (GLUT 4) is sensitive to insulin. Insulin increases GLUT4 membrane expression and synthesis. GLUT 4 is a transport protein that transports glucose into the cell when blood sugar is high. When Insulin is released, Insulin binds to receptors on the cells and tells cells to put more glut 4 receptors on membrane. Essentially, insulin increases the cell’s permeability for glucose and increases concentration of glucose in the cell.
What is glucagon?
Glucagon is am antagonist to insulin and a catabolic hormone. It decreases release of insulin during absorptive state (glucose levels high). Increases release of insulin during post-absorptive state (glucose levels low). Glucagon is secreted by alpha cells in pancreatic islets of Langerhans. Glucagon’s purpose is to raise blood sugar levels. If you body doesn’t produce enough insulin, you have diabetes. If your body doesn’t produce enough glucagon then you are hypoglycemic.
