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
FatMax
The highest intensity of work that can be performed where fat is the primary fuel for energy.
Fat-burning zone
Lower-intensity training where the predominant fuel source is fat, as aerobic pathways can maintain the workload.
Triglycerides
Consist of a glycerol and three fatty acids bound together in a single large molecule.
Adipose tissue
The storage form of fat tissue in the human body, which can be broken down for the liberation of necessary energy.
Lipase
A specific enzyme capable of breaking down lipid molecules in
the body.
Free fatty acids
Liberated lipid molecules found in blood plasma that represent around 10 percent of fat in the body.
Lipolysis
The breakdown of triglycerides from fat storage in the body for potential liberation into circulation to serve energy needs.
Albumin
A blood protein produced in the liver that functions as a transporter for various molecules including FFA, hormones, and calcium.
Lipoproteins
Protein-based compounds that transport various forms of lipids, such as cholesterol, in the bloodstream.
Beta oxidation
The process by which fats are oxidized, or broken down, in the mitochondria to produce acetyl CoA.
Electron transport chain
A group of compounds which expedite a series of oxidation-reduction reactions for eventual aerobic production of ATP within the mitochondria.
Acetyl CoA
Compound that functions as a coenzyme in various biological reactions and is formed as an intermediate for the metabolism of carbohydrates, fats, or proteins in the mitochondria.
Amino acids
Organic molecules consisting of hydrogen, carbon, oxygen, and nitrogen that combine to form the basic elements of proteins.
Branched chain amino acids
These serve as a potential fuel source during long-duration exercise bouts, have a nitrogen-sparing effect, and can bypass the liver and become available for uptake by muscle directly from circulation.
the three BCAAs
Includes leucine, isoleucine and valine
Transamination
A reversible process involved in both anabolism and catabolism by which excess amino acids are diverted toward energy production as an amino group is transferred from one molecule to another.
Oxaloacetate
An intermediate of the Krebs cycle that binds with acetyl-CoA to form
citrate; it helps facilitate aerobic energy production.
Central fatigue
Occurs with insufficient or systemic depletion of CHOs, resulting in reduced motor unit recruitment and firing rate.
General peripheral fatigue
Occurs with a lack of energy in working tissues due to low pre-exercise stores or localized depletion of anaerobic energy store.
Acute peripheral fatigue
Occurs when cells experience dysfunction due to a metabolic reduction in pH.
Rest period
The period of rest in between sets or structured periods of activity within a single exercise bout
Recovery period
The period of time in between separate exercise bouts so adaptations may occur.
Glucagon
Hormone released from the pancreas to promote the breakdown of glycogen to glucose in the liver to aid in blood sugar homeostasis.
Cellular permeability
The ability of nutrients and other substances to pass through the cellular wall: the greater the permeability, the greater the transfer of nutrients and other compounds.
Delayed onset muscle
soreness
Muscle soreness expedited by an inflammatory response to cellular damage, ischemia, and tonic spasms which presents 24-72 hours following an intense bout of exercise.
Graded exercise test
An exercise test which uses progressive stages to measure/estimate maximal oxygen consumption capacity.
Cardiac output
The total volume of blood available for use by all bodily tissues, dictated by heart rate and stroke volume.
A-V O2 difference
The difference in oxygen saturation when comparing the arteries and veins.
Stroke volume
The volume of blood expelled (to body tissues) per contraction from the left ventricle during each heartbeat.
Atria
The two upper chambers in the heart that receive blood from the veins and push it into the ventricles