Definitions Flashcards
Nutrition
Food, vitamins, and minerals that are ingested and assimilated into the body
Assimilation
Process of getting nutrient molecules into the cells of the body and chemically preparing them for use in the chemical reactions of the body.
Metabolism
Process of using nutrient molecules as energy sources and as building blocks for our own molecules.
Catabolism
Breaks nutrient molecules down, releasing their stored energy.
Anabolism
Builds nutrient molecules into complex substances.
Metabolic function of the Liver
A. Secretes bile (physically breaks down large lipid globules)
B. Maintains normal blood glucose level
C. Metabolize carbohydrates, lipids, and proteins; synthesizes several kinds of protein compounds
D. Removes toxins from the blood
E. Stores useful substances
Nutrients
Food components digested, absorbed, and used by the body
Dietary Sources of Nutrients
Macronutrients & Micronutrients
Macronutrients
Nutrients needed in large daily quantities (carbohydrates, lipids, proteins)
Micronutrients
Nutrients needed in tiny daily quantities
Minerals & Vitamins
Carbohydrates
Preferred energy nutrient of the body.
Carbohydrates are primarily catabolized for energy.
Glucose Metabolism
3 series of chemical reactions in glucose metabolism 1.Glycolysis 2.Citric Acid Cycle 3.Electron Transport system
Glycolysis (glucose metabolism)
- Changes glucose to pyruvic acid
- Anaerobic (uses no oxygen)
- Yields small amount of energy; nets adenosine triphosphate (ATP) molecules
- Occurs in cytoplasm
Citric Acid Cycle (Krebs Cycle) (Glucose Metabolism)
- Changes pyruvic acid to carbon dioxide
- Aerobic (requires oxygen)
- Yields large amount of energy (mostly by releasing high-energy electrons to the electron transport system ETS)
- Occurs in the mitochondria
Glucose Anabolism
2 series of chemical reaction in glucose anabolism.
1. Glycogenesis 3. Glycogenysis
Glycogen (Glucose Anabolism)
Glucose that is not needed immediately for making ATP is stored as glycogen (a long chain of glucose subunits) and liver and muscle cells 
Glycogenesis (glucose anabolism)
Anabolic process of joining glucose molecules together in a chain to form glycogen (to store glucose for later use)
Glycogenolysis (glucose anabolism)
Catabolic process of breaking apart, glycogen chains and releasing individual glucose molecules for use in making ATP 
Blood Glucose (blood sugar)
Normally stays between about 80 and 110 mg/ 100 mL of blood during fasting; insulin accelerates the movement of glucose from blood into cells, therefore decreasing blood glucose and increasing glucose catabolism
Lipids
Catabolized to yield energy and anabolized to form adipose tissue 
Proteins (metabolism)
Primarily anabolized and secondarily catabolized.
1. Use of the amine portions of a protein to create energy in the glucose pathway is a process called glucogenesis.
2. Essential amino acids are those that must be in the diet because the body cannot make them. 
Gluconeogenesis
Is a process that uses the amine portions of a proteins to create energy in the glucose pathway 
Essential amino acids
Are those that must be in the diet because the body cannot make them 
Vitamin
Organic molecules that are needed in small amounts for normal metabolism
Minerals
Inorganic molecules found naturally in the Earth required by the body for normal function
Ex. Calcium, iodine and sodium
Regulating food intake
A. Regulatory centers in the hypothalamus play primary role in controlling food intake
B. Food intake, regulations results from balance between hypothalamic control centers.
C. Many diverse factors influence the hypothalamic control centers. 
Appetite center
Produces feeling of hunger
Satiety center
Produces feelings of satisfaction
Basal metabolic rate
Rate of metabolism, when a person is lying down, but awake and not digesting food, and when the environment is comfortably warm
Total metabolic rate
The total amount of energy expressed in calories, used by the body per day
Body temperature
A. Hypothalamus - regulates the homeostasis, a body temperature through a variety of processes
B. Skin - can cool the body by losing heat from the blood through four processes: radiation, conduction, convection, evaporation 
C. The body can generate heat to maintain homeostasis over the short term (shivering) or the long-term (changes in metabolic rate)
D. Heating and cooling a body is controlled by feedback loops that maintain a stable body temperature.

Radiation
Flow of heat waves from the blood and skin
Conduction
Transfer of heat energy to the skin and then to cooler external environment
Convection
Transfer of heat energy to cooler air that is continually flowing away from the skin
Evaporation
Removal of heat from blood vessels in the skin as water sweat vaporizes 
