Chapter 4 – Human Physiology Flashcards
Bioenergetics
Describes the various processes of energy/macronutrient use within the body and relates to the function of various energy systems for fuel provision during exercise.
Enzymes
Protein-based components produced by cells that function to catalyze a biochemical reaction.
Creatine phosphate
An inorganic compound found in skeletal muscle tissue capable of storing and providing high-energy phosphate elements to fuel muscular contractions; along with ATP, it comprises an immediate substrate of the phosphagen system.
Creatine kinase
An enzyme which can catalyze creatine phosphate into creatine and a free phosphate ion to liberate immediate energy within the phosphagen energy system.
Glucose
A simple sugar molecule that provides the primary source of metabolized fuel for the glycolytic energy system.
Glycogen
Storage form of carbohydrates in the body which is broken down to fuel mechanical work: primary storage sites include skeletal muscles and the liver.
Glycolysis
Metabolic process involving the breakdown of sugars (glucose) through a series of reactions to provide energy (ATP) during anaerobic work.
Ischemic
A low oxygen state usually due to obstruction of arterial blood supply or inadequate blood flow leading to tissue hypoxia.
Lactic acid
Energy substrate produced as an end product of glycolysis that can be used by various tissues of the body as fuel to continue ongoing work.
Pyruvate
An energy substrate that results as an end-product of sugar metabolism during glycolysis in the presence of oxygen.
Gluconeogenesis
The creation of new glucose in the liver from other organic molecules, such as pyruvate, lactate, glycerol, and amino acids.
Cori cycle
Name given to the process of lactate and pyruvate recycling in the liver to produce new glucose.
Cytosol
The cytoplasmic fluid which surrounds all organelles within a cell.
Deaminate
The process by which the liver breaks down a protein by removing an amino group for use as potential fuel; glutamate is also deaminated in the kidneys.
Aerobic system
Metabolic pathway wherein the mitochondrion utilizes fats, pyruvate from carbohydrates, and amino acids from protein to produce ATP in the presence of oxygen.
Metabolic equivalent
A measurement of energy use expressed as multiples of the resting `metabolic rate.
1 MET
an oxygen uptake rate of 3.5 ml of O2 per kg of body weight per min of work
Anaerobic system
One of two major metabolic pathways, the ATP-PC phosphagen system or anaerobic glycolysis, that produces energy without the presence of oxygen. Anaerobic systems provide the energy for high power, high intensity activities.
Steady state
A condition within the human body which indicates that the current level of oxygen utilization matches demand, signified by a leveling off or steady heart rate.
Oxygen deficit
The difference between total oxygen consumed during the transition to steady state and the actual amount of oxygen required by the working tissues.
Excess post-exercise oxygen consumption
A measurable increase in the rate of oxygen consumption following strenuous activity due to a deficit created by the work.
Krebs cycle
A series of enzymatic reactions that occur in the mitochondria involving aerobic metabolism of acetyl compounds which produce ATP for cellular energy.
Oxidative phosphorylation
The formation of ATP energy created by the aerobic breakdown of various substrates, especially the organic compounds involved in the Krebs cycle.
Lipids
Various classes of organic compounds composed of fatty acids or their derivatives; dietary sources include oils, fats, waxes, and cholesterol, while endogenous sources include free fatty acids, triglycerides, lipoproteins, and phospholipids