KPE264 key terms

Module 1

• Longitudinal research involves testing the same subjects and comparing results over time
• Cross-sectional research gathers data from diverse populations and compares groups within those populations
• Acute exercise responses happen during a single exercise session
• Chronic exercise responses occur after repeated exercise sessions
• Bioenergetics studies energy transfer through chemical reactions in living organisms
• Enzymes increase the rate of chemical reactions and act as catalysts
• The Enzyme-Substrate complex is a transition state in a reaction
• Product formation is the process of a product being created when a product is combined with an enzyme
• Modulators control breakdown as needed
• Low substrate concentration results in inactive enzymes and a low enzyme rate
• Medium substrate concentration increases binding and the reaction speed
• High substrate concentration leads to maximum enzyme activity, with all enzymes bound
• Stimulators increase enzyme activity at a given substrate
• Inhibition blocks enzyme substrates from binding to the active site
• Stimulation binds to the enzyme, exposing or opening the active site for substrate availabilty
• Metabolism encompasses all chemical reactions in the body
  • Catabolism is the breakdown of molecules and occurs during exercise
  • Anabolism is the synthesis of molecules and occurs during recovery
• Carbohydrates include glucose and glycogen, which are found in muscle
• Lipids include fatty acids that go into the blood, and triglycerides are stored in adipose tissue
• Proteins are made up of amino acids
• Skeletal muscle uses the most oxygen and requires ATP
• The liver breaks down glycogen, and lactate ends up in the liver
• Adipose tissue stores fat as adipocytes and triglycerides
• Myosin ATPase is located in myosin heads and facilitates crossbridge formation
• Na+/K+ ATPase provides energy for sodium transport
• Type I fibers are slow twitch fibers
  • They can sustain exercise for extended periods
  • They rely on oxygen for ATP production
  • They are recruited for low-intensity aerobic activities and daily tasks
  • Highly relied upon in general
• Type II fibers are fast twitch fibers
  • They fatigue quickly and have poor aerobic endurance
  • They are able to produce more force
  • They produce ATP anaerobically
  • Type IIa are more aerobic, while Type IIx are rarely recruited and activate more explosively

Module 2

• The phosphagen system delivers more ATP but cannot sustain it for very long
• The glycolytic system can be relied on for a moderate amount of time
• The oxidative system remains effective for extended durations
• Phosphocreatine quickly buffers against ATP decreases
• Creatine supplementation increases Cr + ATP, which leads to ADP + PCr
• Non-oxidative glycolysis partially breaks down glucose/glycogen without oxygen and is less efficient
  • The process is fast but limited by metabolic by-products, restricting long-term use and creating 2-3 ATP units per substrate
• Glycolysis breaks down one glucose molecule to form two pyruvate molecules
• Glycogenolysis breaks down one 6-carbon glucose unit from glycogen, forming glucose-1-phosphate
• The GLUT transporter allows glucose to enter the muscle during exercise
• Hexokinase traps glucose inside the muscle
• Phosphofructokinase (PFK) is a crucial enzyme in the glycolytic system
• Substrate-level phosphorylation generates ATP in the absence of oxygen
• NADH is a high-energy substrate that is used in the ETC to generate ATP
• Metabolic inhibition decreases enzyme activity and the ability to continue the pathway, where H+ interferes with PFK
• Contractile inhibition decreases crossbridge cycling, affecting actin and myosin and lowering their overall efficiency
• Lactate is an anion formed in aerobic conditions
  • It serves as a primary source for mitochondrial respiration
  • It serves as a major gluconeogenic precursor
  • It acts as a signaling molecule
  • It stimulates mitochondrial growth
• Oxidative metabolism involves the complete breakdown of carbohydrates, fats, and amino acids into CO2 and H2O
  • This process extracts all potential energy from carbohydrates and fats
• Mitochondria are the powerhouse cells, pumping H+ across the intermembrane
• Carbohydrate oxidation forms acetyl coA from carbohydrates
  • Pyruvate (3C) + NAD via pyruvate dehydrogenase yields acetyl coA (2C molecule) + CO2 + NADH
• Pyruvate dehydrogenase (PDH) is an enzyme in the mitochondria used in carbohydrate oxidation
• NADH is utilized in oxidative phosphorylation and is found in glycolysis and oxidizes in ETC
• Oxidation is the loss of electrons
• Reduction is the gain of electrons
• The Electron Transport Chain (ETC) is a sequence of oxidation-reduction reactions where electrons are passed from NADH and FADH2 to O2
• Cytochrome oxidase transfers H+ to O2 to produce H2O
• ATP synthase facilitates ATP generation at the end of the ETC
• Oxidative phosphorylation also known as the “chemiosmotic theory” generates ATP through H+ ion movement across a membrane
• Triglyceride (TG) is composed of glycerol + 3 fatty acids
• Hormone-sensitive lipase (HSL) stimulates the breakdown of TG in adipose and muscle tissue
• Fatty acetyl-coA is recognizable by mitochondria
• Carnitine palmitoyl transferase (CPT) moves fatty acids into the mitochondria
• Carnitine acts as a key escort for fatty acids, and is an important component of CPT
• Beta Oxidation occurs before the Krebs cycle
  • This is a key step where fatty acids run through the Krebs cycle
  • Occurs 7 times until the final 2-carbon unit remains
• An amino acid (AA) is made up of an amino group, an R group, and a carboxyl group
• Gluconeogenesis is the creation of "new glucose" from metabolic intermediates

Module 3

• Triglyceride (TG) is composed of glycerol + 3 fatty acids
• Hormone-sensitive lipase (HSL) stimulates the breakdown of TG in adipose and muscle tissue
• Fatty acetyl-coA is recognizable by mitochondria
• Carnitine palmitoyl transferase (CPT) moves fatty acids into the mitochondria
• Carnitine acts as a key escort for fatty acids, and is an important component of CPT
• Beta Oxidation occurs before the Krebs cycle
  • This is a key step where fatty acids run through the Krebs cycle
  • Occurs 7 times until the final 2-carbon unit remains
• An amino acid (AA) is made up of an amino group, an R group, and a carboxyl group
• Gluconeogenesis is the creation of "new glucose" from metabolic intermediates
• The Wingate bike test measures anaerobic performance
  • It is a 30-second all-out test against high break force at 0.075kg/kg body mass resistance
• Calorimetry measures aerobic metabolism
  • Direct calorimetry measures heat production
  • Indirect calorimetry measures oxygen utilization at the mouth
• The respiratory exchange ratio (RER) is the ratio of CO2 produced to O2 consumed, where RER = VCO2/VO2
• Oxygen uptake at rest measures the body's rate of O2 utilization
• VO2 refers to the consumed volume of O2 per minute measured in L/min or mL/min (absolute) or mL/kg/min (relative to body mass)
• 1 MET defined as “metabolic equivalent” equals 3.5 ml O2/kg/min
• Lactate threshold signifies an exercise intensity where blood lactate abruptly increases
  • It reflects the capacity to sustain oxidative metabolism and aerobic activity
• Neuroendocrinology involves the combined actvity of organs and tissues
  • These regulate hormone release and bodily function
• A hormone is a chemical that is secreted into bodily fluids which has specific results on distant and local targets
• Nonsteroid/"peptide hormones" are derived from proteins, peptides, or amino acids and are not lipid soluble
  • Due to being not lipid soluble, they are unable to cross cell membranes
  • Hormones are released from the pancreas, hypothalamus, pituitary gland, and adrenal medulla
• Steroids come from lipids like cholesterol and are lipid-soluble so that they can cross cell membranes
  • They are released from the ovaries, testes, and adrenal cortex
• Insulin is a gluco-regulatory hormone
• Glucagon reverses the effects of insulin by being a gluco-regulatory hormone
• Epinephrine increases muscle and liver glycogenolysis
• Norepinephrine increases lipolysis in adipose tissue and cardiorespiratory function

Module 4

• The respiratory system facilitates air intake, diffusion of O2 and CO2 in the lungs and muscles, and CO2 output from the body
• External respiration includes
  • Pulmonary ventilation which is the movement of air flowing in/out of the lungs
  • Pulmonary diffusion is the gas exchange between the lungs and blood at the alveoli
• Internal respiration includes
  • Gas transport which is the movement of O2 and CO2 via the blood
  • Capillary diffusion which is the pas exchange between blood and tissues like the liver and skeletal muscle
• Tidal volume (VT) measures air moved per breath
• Alveolar volume measures inspired air that reaches the alveoli
  • Alveolar volume is equal to tidal volume minus dead space volume, with dead space volume representing trapped air
• Minute Ventilation (VI or VE) measures total airflow in the lungs, and equals VT times Respiratory Rate (RR)
• Alveolar ventilation (VA) measures total airflow in the alveoli,and equals VA times frequency or (VT-VD) x RR
• Pulmonary Diffusion the exchange between the alveoli and pulmonary capillaries
• Partial pressure PO2 is the portion of total pressure from the presence of a single gas, and can vary at high altitudes
• Atmospheric pressure changes due to gravity, attracting molecules closer to the earth's surface
• Hemoglobin (Hgb) contains a heme group and alpha and beta subunits, binding and transporting O2
• The oxyhemoglobin dissociation curve shows
  • When loading, saturation stays high even with large changes in PO2
  • When unloading, saturation changes rapidly even with small changes in PO2, allowing oxygen release to muscles (muscle level/veins)
• Arterial blood has higher PO2 values with more O2 bound to hemoglobin
• Venous blood has lower PO2 values with less O2 bound to hemoglobin
• Affinity measures the ability of O2 to bind to hemoglobin
• Shifting of the oxyHgb dissociation is
  • Leftward shift increases affinity
  • Rightward shift decreases affinity
• Myoglobin is made of globin plus heme and is only found in the muscle
  • Binds O2 much tighter than Hgb and shuttles O2 to the mitochondria
• Carbaminohemoglobin has CO2 bound to amino acids on hemoglobin without competing for the same O2 binding site
• Carbonic anhydrase is an important enzyme in red blood cells
• Respiratory centers mediate inspiration and expiration
  • Located in the brain stem, establishing breah signals for respiratory muscles
  • The cortex can override these signals like voluntary holding
• Neural signals
  • Central command from the brain
  • Signals from active muscle
• Chemical signals
  • Central chemoreceptors in teh brain are stimulated by increased CO2 and increased H+ in cerebrospinal fluid
    • These increase rate and depth of breathing and remove excess CO2 from the body
  • Peripheral chemoreceptors sense changes in arterial blood PO2, PCO2, and H+
    • Work within a tight range of values
    • Small changes
• Mechanoreceptors and stretch receptors are in the lungs
  • Found in pleurae, bronchiole, and alveoli
  • Sense movement with increased breathing and increased exercise
• Voluntary control comes via the motor complex
  • Breathing rate can be adjusted by choice

Module 5

• The Cardiovascular (CV) System involves transporting gases and hormones to muscle tissue in addition to removing waste products
• The aortic valve moves blood from the left ventricle
• The mitral valve is also known as the bicuspid valve
• The pulmonary valve sends blood to rejuvenate in the lungs
• The tricuspid valve receieves deoxygenated blood
• Semilunar valves are aortic and pulmonary
• Atrioventricular valves are mitral and tricuspid
• Atrioventricular (AV) valves regulate blood flow within the heart, and between the atria and ventricles
  • This allows one way flow that avoids backflow
  • Pressure drives blood flow
  • Opening of the AV valve generates an "LUB" sound
• Semilunar (SL) valves controls blood flow out of of the heart into the systemic and pulmonary flow
  • Closing of teh SL valve generates "DUB" sounds
• The SA node which is in the upper posterior wall wall serves as the hearts pacemaker and signals the atria to contract
• The AV node delays and relays signals from the heart to the ventricles, allowing atrial blood maximiziation
• Purkinje fibers are
  • Terminal branches of right and left bundle branches
  • Spread throughout the entire ventricle wall
  • Stimulate ventricular contraction and ejection of blood from the heart
  • Controls heartbeat

Module 6

• The electrocardiogram (ECG) records electrical activity of the heart
  • Atrial depolarization (P wave) is when electric impulses travel from the SA node and stimulate atria contraction
  • Ventricular depolarization(QRS complex) occurs simultaneously as impulse bundles spread through ventricles
  • Ventricular repolarization (ST segment) ends with ventricular contraction
  • Ventricular repolarization (T wave) sees the continuation of ventricular activity
  • The PR interval includes AV delay
  • ventricular depolarization plus the ventricular repolarization equals the QT interval
• The cardiac cycle consists of both mechanicala and electricals events between successive heartbeats
  • Systole is when ventricles eject blood during ventricular contracion
  • Diastole is blood flowing through the the ventricles during relaxation
• Cardiac cycles involve
  • Ventricular filling
  • Isovolumetric contraction which sees no changes in blood volume
  • Ventricular ejection
  • Isovolumetric relaxation with all valves shut
• Ventricular pressure changes during the cardiac cycle involves.
  • Ventricular filling where atrial pressure is high
  • Ventricular where ventricular pressure is higher than atriaa, resulting in hearts walls contracting
  • SL valves opening while the ventricles push blood with high aorta
  • SL valves closing when the ventricular pressure drops

Module 7

• End Diastolic Volume (EDV) represents the volume of blood with the ventricles, indicating stretch due to filling
• Stroke Volume (SV) signifies the volume of blood pumped across the ventricular walls
• "Ejection fraction" measures the blood volume pumped out from the ventricular area at a rate of 60%
• End Systolic Volume (ESV) - volume of blood remaining in ventricle at end of systole
• “Muscle Pump” - the contraction of skeletal muscles compress veins
• Frank-Starling Law of the Heart involves incraesed ventricular strength generated by previous muscle contraction
  • incr. EDV → incr. stretch on walls → incr. force of contraction → incr. SV
  • force generated by contracting ventricle is greater when muscle is previously stretched (i.e greater filling = stronger subsequent contraction)
• Cardiac output (Q) measures the total blood pumped, with higher heart rate indicating greater blood generation
  • Cardiac Output (Q) - total volume of blood pumped by ventricle per min; Q = HR x SV
    • chronotropic - rate of contraction (i.e HR)
    • inotropic - strength of contraction (i.e SV)
• Maximal HR (HRmax) indicates the greatest the heart pumps during effort
  • Maximal HR (HRmax) - highest HR achieved in all-out effort to volitional fatigue
    • estimated HRmax = 220-age (±10 bpm) OR 208 - (0.7 x age)
• SVmax = semi-adjustable (genetics & training)
• Intrinsic control of HR - pacemaker (SA node)
• Extrinsic control of HR - PNS, SNS, Hormones
• Extrinsic control of HR from the parasympathetic nervous system decreases heart rate
  • The vagus nerve travels from the brain stem to the SA and AV nodes, releases acetylcholine
    • vagus nerve travels from brain stem (medulla oblongata) to the heart (SA & AV nodes)
• Sympathetic Nervous System (SNS) increases and increases heart rate
  • Cardiac accelerator nerves travel travels from brain stem to the heart
    • Innervates the SA and AV nodes and ventricles affecting stroke SV C- ardiac accelerator nerves release norepinephrine
      • cardiac accelerator nerve travels from brain stem to the heart (SA & AV nodes & ventricles)
        • innervates @ SA & AV nodes & ventricles (affects stroke SV)
• Cardiac output is altered by
  • Mechanoreceptors through Starlings law
  • C -Mechanoreceptors
    • senses mechanical movement
    • can influence augmentation in SV
    • starling law of the heart - greater filling of heart, results in larger SV
  • Circulating NE and EPI
  • Circulating NE & EPI - influences SA node, AV node, ventricles
• Vagus nerve - down-regulating
  • Cardiac accelerator nerve - up-regulating
• The vessels involved transport blood from heart to body to generate
  • The Vasculature - vessels that transport blood from heart to tissues, back to heart; blood movement: arteries → arterioles → capillaries → veins
• Vasculature influences cardiac activity
  • arteries - establish “bulk flow” & driving pressure, moves blood from heart to arterioles
  • Arterioles drive pressure with vasoconstriction and vasodilation
  • arterioles - regulates flow to specific regions (vasoconstric/vasodilate - incr./decr. size) [greatest control of circulation]
  • Capillaries regulate surface area
  • capillaries - regulate surface area for exchange
• Veins and venules use muscle pumps to regulate flow return
  • veins/venules - regulates flow return (“muscle pump” - squeezing of veins)
• Hemodynamics are the influence of flow, resistance, and blood
  • Hemodynamics; dynamics of blood circulation → flow, pressure, resistance
  • Flow equals pressure by resistance
  • flow = pressure change / resistance
• Resistance equals tonic viscosity and radius
  • Resistance = (Viscosity x length) / radius4
• Vascularity is controlled by intrinsic factors
  • vascular tone - state on tonic vasoconstriction
    • Vasculature: Intrinsic Control
      • 1. Metabolic regulation*
        • changes in O2, CO2, H+ & incr. temp cause release of vasodilatory chemical
      • 2. Endothelium-mediated dilation*
        • nitric oxide, acetylcholine, & adenosine cause vasodilation
      • 3. Myogenic response
        • incr. pressure = vasoconstriction
        • decr. pressure = dilation
        • goal is to maintain blood flow
• Incr. SNS → incr. norepinephrine (NE) release = vasoconstriction in most tissues (external factor)
• “local” factors = vasodilation in active muscle
• Blood pressure is impacted by the Fick Equation
• Fick Equation” → VO2 = Q x (a-v O2 diff)
  • total O2 consumption by tissue depends on amount of blood delivered to tissue & amount of O2 extracted

Module 8

• Resistance changes are key: changes in O2, CO2 can vasodilate
• Mean arterial pressure is the average pressure during cycles
• Mean Arterial Pressure (MAP) - average driving pressure during cardiac cycle
  • aMap is systolic blood pressure, diastolic blood pressure and calculated value
  • MAP = DBP + [⅓ (SBP-DBP)]
• “Central limitations can affect oxygen deliver to muscles
• “Central limitations” effects on O2 delivery to muscles - max cardiac output - optimal gas exchange @ lungs - ability of blood to carry oxygen “-“Peripheral Limitations” effect on O2 utilization/extraction by muscles mitochondrial content capillarization of muscle fibres
• VO2 max is the highest value
• SV ↑ = EDV ↑ - ESV ↓
• VO2max = HRmax x SVmax x (a-v O2 diff)max
• Which way does the curve shift in the arteries
• Which way does the curve shift during exercise? - right
• What causes the curves to be this style
• what causes the curve to shift? - temp & pH
• This is the function of PH
• what does the exercise-induced shift promote? - offloading @ the tissues

Module 9

• Insulin resistance is influenced- insulin sensitivity - how easily your cells respond to insulin’s signal to take up glucose from the blood
• insulin resistance - your cells don’t respond well, so your body needs more insulin to do the same job Increase in Glycogen is post exercise with glycogen synthesis and a demand for uptake diabetics - lose ability to react to glucose incr. glycogen use during exercise → incr. post-exercise glycogen resynthesis → incr. demand for glucose uptake post-exercise glycogen resynthesis
  • carbs get diverted to storage in muscle; ∴ less remains in blood circulation
    • not affect = lower blood glucose concentration
• Demand for glucose increases insulin effectiveness
• Demand for glucose uptake - more responsive to insulin @ lower concentration
• Sex and gender influences
• Sex - biologically determined; assigned at birth, based on reproductive organ, chromosome -Gender - socially or culturally determined; how one identifies
• Cardiovascular change via sizedependant exercise values
• Changes in CV responses to exercise in children over time: size-dependant - stroke volume size-independent - heart rate
• Children and size
  • Heart size - grows parallel with body dimensions
  • ventilation responses to exercise in children - largely size-dependent