BTEC Level 3 Sport & Exercise Physiology: Comprehensive Unit 1 Study Guide

Comprehensive vocabulary flashcards covering the anatomy, physiological acute responses, chronic adaptations, energy systems, fatigue mechanisms, and environmental factors from Unit 1 Sport and Exercise Physiology.

Aerobic

A state or process in which the body uses oxygen to produce energy.

Anaerobic

A state or process in which energy is produced by the body without the presence of oxygen.

Acute Responses

The body's immediate physiological reactions to exercise, such as changes that occur during or after a single exercise or training session.

Chronic Adaptations

Long-term physiological adjustments to the body that occur as a result of regular training over time, typically requiring a minimum of $6\text{--}8\,\text{weeks}$ of consistent exercise.

Bone Remodelling

The continuous cyclical process of skeletal adaptation where osteoclasts break down old bone tissue and osteoblasts synthesize new bone matrix to withstand physical demands.

Osteoclasts

Bone cells that break down and resorb old bone tissue following weight-bearing activity, releasing calcium and other minerals into the bloodstream.

Osteoblasts

Bone cells responsible for laying down collagen, minerals, and new bone tissue to rebuild stronger bones and increase bone density in response to exercise stress.

Osteocytes

Mature bone cells formed from osteoblasts that assist in maintaining mineral content and structural strength within bone tissue.

Synovial Fluid

A lubricating fluid secreted into synovial joint cavities by the synovial membrane that decreases in viscosity during movement to lubricate joints and reduce friction.

Viscosity

The thickness or internal friction of a fluid; synovial fluid viscosity decreases during physical activity to allow a greater range of motion.

Micro-tears

Microscopic damage caused to muscle fibres by overloading or placing additional stress on muscles during training, which stimulates protein synthesis and muscle repair.

Muscle Fibre Recruitment

The progressive activation of motor units in a ramp-like pattern depending on exercise intensity, ensuring not all fibres contract simultaneously to prevent injury.

Type I Muscle Fibres

Slow-twitch muscle fibres highly resistant to fatigue, adapted for low-intensity, long-duration aerobic work, and recruited at the beginning of exercise regardless of intensity.

Type IIa Muscle Fibres

Fast-twitch oxidative glycolytic fibres used for high-intensity anaerobic work that can be trained through endurance training to take on aerobic characteristics.

Type IIx Muscle Fibres

Fast-twitch glycolytic muscle fibres recruited when maximal force and explosive muscular power are required.

Medulla Oblongata

The respiratory control centre in the brainstem that monitors chemical levels of $\text{O}_2$ and $\text{CO}_2$ in the blood to regulate breathing rate.

Anticipatory Rise

An initial increase in heart rate or breathing rate prior to the onset of exercise, triggered by neurotransmitters like adrenaline in preparation for physical effort.

Tidal Volume (TV)

The volume of air inhaled or exhaled in a single breath, with an average resting value of approximately $0.5\,\text{L}$, which increases significantly during exercise.

Minute Ventilation (VE)

The total volume of air ventilated into or out of the lungs per minute, calculated using the formula: $\text{Minute Ventilation (VE)} = \text{Breathing Rate (BR)} \times \text{Tidal Volume (TV)}$.

Bohr Effect

The rightward shift of the oxygen-haemoglobin dissociation curve caused by increased carbon dioxide, increased muscle temperature, and decreased blood pH, which reduces haemoglobin affinity for oxygen to enhance oxygen delivery to active tissues.

Affinity

The strength of attraction between two substances, such as the chemical binding strength between haemoglobin and oxygen molecules.

Cardiac Output (Q)

The volume of blood pumped out of the left ventricle of the heart into systemic circulation per minute, calculated as: $\text{Cardiac Output (Q)} = \text{Heart Rate (HR)} \times \text{Stroke Volume (SV)}$.

Stroke Volume (SV)

The quantity of blood ejected from the left ventricle of the heart during a single mechanical contraction.

Starling's Law of the Heart

The physiological mechanism stating that increased venous return stretches ventricular walls during diastole, resulting in more forceful myocardial contractions and higher stroke volume during systole.

Systolic Blood Pressure

The pressure exerted against arterial walls when the heart contracts and actively pumps blood out into the body.

Diastolic Blood Pressure

The pressure maintained in the blood vessels when the heart muscle is relaxed between contractions and refilling with blood.

Vasodilation

The widening of the internal lumen of blood vessels to increase localized blood flow toward metabolically active tissues such as working skeletal muscles.

Vasoconstriction

The narrowing of blood vessel lumens to restrict blood flow away from inactive regions, such as the gastrointestinal tract during intense exercise.

Arteriovenous Oxygen Difference (a-VO2 diff)

The difference in oxygen concentration between arterial blood arriving at active tissues and mixed venous blood returning from them, which widens during exercise as muscles extract more oxygen.

Neurons

Specialized nerve cells classified as sensory neurons, interneurons, or motor neurons that transmit electrical signals throughout the nervous system.

Sensory Neurons

Nerve cells that transmit sensory impulses from periphery receptors and the skin toward the central nervous system.

Motor Neurons

Efferent nerve cells that transmit motor impulses from the central nervous system outward to skeletal muscle fibres to initiate muscular contractions.

Interneurons

Central nervous system nerve cells that form neural communication links between sensory neurons and motor neurons.

Neuromuscular Junction

The synapse site where a motor neuron terminal axon communicates with a muscle fibre end plate across a synaptic cleft via neurotransmitter release.

All-or-None Law

The neuromuscular principle stating that when an action potential reaches the threshold in a motor unit, all muscle fibres connected to that unit contract simultaneously to their maximum capacity, or none contract.

Acetylcholine (ACh)

A chemical neurotransmitter stored in synaptic vesicles that is released into the synaptic cleft to transmit an action potential across to a muscle fibre.

Chemoreceptors

Sensory receptor cells that detect internal changes in chemical composition, such as increases in carbon dioxide and decreased blood pH.

Thermoreceptors

Sensory receptors that detect variations in core and skin body temperatures, relaying signals to the hypothalamus to govern thermoregulation.

Baroreceptors

Sensory stretch receptors situated in arterial walls that detect fluctuations in blood pressure.

Proprioceptors

Specialized sensory organs situated in muscles, tendons, and joints that monitor body position, tension, stretch, and movement kinematics.

Muscle Spindles

Intrafusal sensory proprioceptors embedded within skeletal muscles that detect changes in muscle length and stretch velocity, initiating a protective stretch reflex to trigger contraction and resist tears.

Golgi Tendon Organ (GTO)

A proprioceptor located within muscle tendons that detects high mechanical tension; excessive tension causes a reflex arc that inhibits further contraction to protect against tendon damage.

Endocrine System

An organ system composed of specialized glands and tissues that synthesize and secrete hormones into the bloodstream to regulate physiological processes.

Adrenaline

An adrenal hormone that triggers the fight-or-flight response, increasing heart rate, blood pressure, and metabolic rate during exercise stress.

Cortisol

A steroid hormone secreted by the adrenal cortex that governs the stress response, increases blood glucose concentration, and facilitates nutrient metabolism.

Glucagon

A pancreatic hormone that stimulates glycogen breakdown to elevate circulating blood glucose levels when blood sugar drops.

Insulin

A hormone produced by the pancreas that promotes the uptake of circulating glucose into cells, lowering blood glucose concentration.

Human Growth Hormone (HGH)

An anterior pituitary hormone that regulates metabolism, energy levels, tissue repair, and cellular development.

Adenosine Triphosphate (ATP)

The primary biochemical currency of energy composed of adenosine and three phosphate groups, which yields energy when broken down by ATPase.

ATPase

The enzyme responsible for cleaving the terminal high-energy phosphate bond of ATP to produce adenosine diphosphate (ADP), inorganic phosphate (P), and usable energy.

ATP-PC System

An immediate anaerobic energy system that uses intramuscular phosphocreatine (PC) stores to rapidly rephosphorylate ADP back into ATP for short-duration maximal efforts lasting up to $10\,\text{seconds}$.

Lactate System

An anaerobic energy pathway, also termed anaerobic glycolysis, that partially breaks down glucose and glycogen without oxygen to form ATP and lactic acid, sustaining high-intensity activity for $60\text{--}90\,\text{seconds}$.

Aerobic System

The long-term mitochondrial energy system that fully metabolizes glycogen and fatty acids with oxygen to synthesize large amounts of ATP, yielding non-fatiguing water and carbon dioxide.

Aerobic Glycolysis

The first phase of aerobic metabolism where glucose or glycogen undergoes a sequence of 10 enzymatic reactions to produce pyruvate and a net yield of $2\,\text{ATP}$.

Krebs Cycle

The second phase of aerobic metabolism taking place in the mitochondria, where acetyl coenzyme A is oxidized to generate $2\,\text{ATP}$, carbon dioxide, and hydrogen ions for subsequent stages.

Electron Transport Chain

The final stage of aerobic metabolism in the mitochondrial inner membrane, where accepted hydrogen ions combine with oxygen to yield $34\,\text{ATP}$ molecules and water.

Energy Continuum

The concept that all three energy pathways operate simultaneously, with their proportional contribution depending on the intensity and duration of the physical activity.

Onset of Blood Lactate Accumulation (OBLA)

The exercise intensity point at which blood lactate production exceeds clearance, typically marked when lactate levels reach approximately $4\,\text{mmol/L}$.

Fatigue

The exhaustion of a muscle resulting from prolonged exertion or neuromuscular over-stimulation, impairing its ability to produce mechanical force.

Excess Post-Exercise Oxygen Consumption (EPOC)

The elevated volume of oxygen consumed during recovery above normal resting baselines to replenish ATP, resynthesize phosphagen, and catabolize accumulated lactic acid.

Alactacid Component of EPOC

The fast recovery phase of EPOC that uses additional oxygen during the initial $3\,\text{minutes}$ post-exercise to resynthesize approximately $99\%$ of depleted ATP and phosphocreatine stores.

Lactacid Component of EPOC

The slow recovery component of EPOC requiring additional oxygen to break down and clear accumulated lactic acid into carbon dioxide and water or convert it into glycogen via gluconeogenesis.

Gluconeogenesis

The metabolic pathway through which the liver synthesizes glucose or glycogen from non-carbohydrate carbon substrates, such as lactic acid during post-exercise recovery.

Overtraining

A chronic state of systemic exhaustion caused by an imbalance between high training volume/intensity and inadequate rest, nutrition, or sleep, leading to reduced performance and elevated injury risk.

Hypertrophy

An increase in muscle cross-sectional area and overall muscle size resulting from long-term resistance or strength training.

Hyperplasia

The longitudinal splitting of existing muscle fibres leading to an increase in the total number of muscle fibres.

Capillarisation

The chronic development and proliferation of capillary networks surrounding muscle fibres and pulmonary alveoli to optimize gaseous exchange and nutrient delivery.

Cardiac Hypertrophy

The structural enlargement of heart dimensions, particularly left ventricular wall thickness and cavity chamber capacity, causing higher stroke volumes.

VO2 Max

The maximum rate of oxygen consumption measured in millilitres per kilogram per minute, indicating an individual's cardiorespiratory and aerobic endurance capacity.

One-Repetition Maximum (1RM)

The maximum amount of force or weight a muscle or muscle group can exert in a single maximal effort, used to evaluate muscular strength.

Anaerobic Power

The capacity of the neuromuscular system to generate high levels of force and explosive work rapidly at speed without oxygen.

Hypoxia

A condition characterized by insufficient oxygen availability to body tissues, commonly induced by reduced atmospheric partial pressure of oxygen at high altitude ($2400\,\text{m}+$).

Acclimatisation

The adaptive process by which an organism adjusts to environmental stressors such as high altitude or heat over time to sustain physiological performance.

Hypothalamus

The region of the brain that serves as the body's central thermostat, coordinating autonomic thermoregulatory responses to maintain a core temperature of around $37\,^{\circ}\text{C}$.

Convection

The transfer of thermal energy away from the body through the bulk movement of air or water currents across the skin surface.

Conduction

The direct transfer of thermal energy between two physical bodies in physical contact, always travelling from the warmer object to the cooler object.

Radiation

The loss or gain of heat energy via electromagnetic infrared waves between surfaces without physical contact.

Evaporation

A vital heat dissipation mechanism wherein sweat fluid on the skin surface absorbs heat energy and vaporizes into gas.

Shivering Thermogenesis

An involuntary, rhythmic contraction of skeletal muscle fibres activated in extreme cold environments to generate metabolic body heat.