Energy Production, Metabolism, and the Ventilatory System

Vocabulary practice flashcards covering cellular bioenergetics, metabolic systems, ventilatory anatomy, mechanics of breathing, and respiratory control mechanisms.

Metabolism

All the biochemical reactions occurring within an organism, encompassing both anabolic and catabolic pathways.

Anabolic Reactions

Energy-requiring chemical reactions where smaller molecules are built into larger, complex organic compounds.

Catabolism

Chemical reactions that break down larger molecules into smaller ones ("cata" meaning destruction); includes aerobic catabolism (requires oxygen) and anaerobic catabolism (does not require oxygen).

Condensation Reactions

Chemical reactions that bond two molecules together via the removal of water.

Carbohydrates

Nutrients obtained from fruit, dairy, bread, rice, and pasta used for energy production; stored as glycogen in muscle and liver, producing approximately $1760\,\text{kJ}$ of energy per $100\,\text{g}$, and accounting for $50\text{--}60\%$ of nutrient intake.

Lipids (Fats)

Nutrients sourced from meat, dairy products, oils, and nuts used for long-term energy storage, insulation, cell membrane structure, and hormones; stored as triglycerides in adipose tissue with three fatty acids, yielding $4000\,\text{kJ}$ per $100\,\text{g}$, and making up approximately $30\%$ of nutrient intake.

Adenosine Triphosphate (ATP)

The controlled currency of energy in cells released from organic compounds; energy is stored by the anabolic synthesis of ATP from adenosine diphosphate (ADP) and released via the catabolism of ATP to ADP.

Phosphagen System (ATP-PC)

An immediate energy system that functions without oxygen, utilizing creatine phosphate (PC) to rapidly resynthesize ATP from ADP for up to $10\,\text{seconds}$.

Anaerobic Glycolysis

The breakdown of glucose in the cytoplasm without oxygen to produce pyruvate and a net yield of $2\,\text{ATP}$.

Lactic Acid Fermentation

The anaerobic conversion of pyruvate into lactic acid; yields $2\,\text{ATP}$, but the accumulation of lactic acid causes muscle fatigue, discomfort, and a reduced ability to contract.

Oxidative Phosphorylation (Cellular Respiration)

A long-term aerobic energy pathway occurring in the mitochondria that uses oxygen and the electron transport chain (ETC) via glucose oxidation and fatty acid beta-oxidation to generate $36\text{--}38\,\text{ATP}$.

Creatine Phosphate (PC)

A high-energy compound that restores ADP to ATP quickly without oxygen by donating a phosphate molecule ($\text{PC} + \text{ADP} \rightarrow \text{ATP} + \text{creatine}$), sustaining energy regeneration for up to $10\,\text{seconds}$.

ATP-PC Energy System Characteristics

An energy pathway that supports maximal effort bursts (e.g., $100\,\text{m}$ sprint, max lift) utilizing Type 2a and Type 2x muscle fibers without oxygen; limited by rapid depletion within $10\,\text{seconds}$ and a long recovery requirement.

Glycolytic Energy System Characteristics

An energy pathway providing quick ATP for high-intensity efforts lasting $10\,\text{seconds}$ to $2\,\text{minutes}$ (e.g., $400\,\text{m}$ sprint) using explosive Type 2 fibers; limited by lactate accumulation, dependency on sugar, and inefficient ATP yield.

Oxidative Energy System Characteristics

A highly efficient energy pathway supporting sustained, enduring exercise (e.g., marathon, soccer game) using Type 1/1A fibers and fats as a fuel source; limited by slow ATP production and absolute dependence on oxygen.

Maximal Oxygen Consumption ($\text{VO}_2\,\text{max}$)

A measurement of aerobic capacity and fitness expressed in milliliters per kilogram of body weight per minute ($\text{mL/kg/min}$); higher values signify more efficient energy production, greater $\text{O}_2$ delivery, and superior endurance.

Ventilatory Homeostasis

The maintenance of internal equilibrium by the ventilatory system via gas exchange ($\text{O}_2$ and $\text{CO}_2$ transfer), temperature regulation, waste removal, and blood pH maintenance within $7.35\text{--}7.45$ (preventing acidosis and alkalosis).

Pulmonary Respiration

The physical process of moving air mechanically into and out of the lungs.

External Respiration

The exchange of oxygen ($\text{O}_2$) and carbon dioxide ($\text{CO}_2$) between the alveoli of the lungs and the blood.

Internal Respiration

The exchange of oxygen ($\text{O}_2$) and carbon dioxide ($\text{CO}_2$) between the circulating blood and the active muscle tissues.

Pharynx

An anatomical structure that fights infections and directs the controlled flow of liquids and food into the esophagus.

Larynx

An airway structure responsible for preventing swallowed food from entering the respiratory tract.

Epiglottis

A protective flap of cartilage that covers and blocks the trachea during swallowing to guard the entryway to the lower airway.

Trachea

The primary airway leading to the lungs, reinforced with cartilage rings, lined with mucus, and guarded by microscopic hairs for defense against harmful substances.

Bronchi and Bronchioles

The conductive branching network where the trachea splits into the left and right bronchus, which further divide into smaller bronchioles that lead directly to the alveoli.

Alveoli

Microscopic air sacs that serve as the actual site of external gas exchange, structured with single-cell thickness to enable rapid diffusion alongside adjacent single-cell-thick capillary beds.

Lung Lobes

Anatomical divisions that increase the functional surface area of the lungs; the right lung is composed of $3\,\text{lobes}$ while the left lung is composed of $2\,\text{lobes}$.

Conducting Airways

Low-resistance passages that warm (via blood vessels), moisten (via vapor), and filter incoming air while using mucus-covered microscopic hairs in the trachea and bronchi as a defense against harmful particles.

Inspiration

The active act of breathing in, during which the diaphragm contracts and flattens while external intercostal muscles contract to elevate the ribs, expanding the chest and increasing thoracic cavity volume.

Expiration

The act of breathing out, during which the diaphragm relaxes and curves upward while internal intercostal muscles contract to pull the ribs downward, contracting the chest and decreasing thoracic cavity volume.

Boyle's Law (Ventilation)

The physical law stating that pressure and volume are inversely proportional; expanding thoracic volume reduces internal pressure causing air to flow inward, whereas reducing volume increases pressure to force air out.

Diffusion (Gas Exchange)

The passive movement of gas molecules from an area of high concentration or pressure to an area of low concentration or pressure without expenditure of cellular energy.

Chemical Control of Respiration (pH & Acidity)

The receptor-driven monitoring of blood and environmental pH, wherein increased acidity (caused by elevated acidifying $\text{CO}_2$) stimulates an increase in ventilatory volume.

Lung Stretch Receptors

Specialized sensory receptors located within the lungs that monitor expansion to safeguard against overinflation.

Muscle Proprioceptors

Sensory receptors embedded in muscles that provide continuous feedback regarding body movement and spatial orientation to assist in regulating respiration.