Physical Activity, Fitness, Performance, and Control of Internal Environment

Vocabulary-style flashcards covering the basics of exercise physiology, factors affecting performance, and biological control systems as discussed in the lecture notes and textbook chapters.

Physical Activity

Any bodily movement produced by skeletal muscles that results in energy expenditure.

Exercise

A subcategory of physical activity that is planned, structured, repetitive, and has the purpose of improving physical fitness.

Non-exercise Activity Thermogenesis (NEAT)

Physical activity that is not exercise-related.

Physiology

The study of the function of cells, tissues, and organ systems (e.g., muscle, nerve, heart, lungs).

Exercise Physiology

The study of exercise on the function of body cells, tissues, and organ systems, including responses in differing environments and specific populations.

Power

A calculation determined by $\frac{\text{force} \times \text{distance}}{\text{time}}$.

Fatigue

The inability to maintain power output, resulting in reduced performance.

Ultra Short-Term Performances

Events lasting less than $10\,s$, influenced by factors like muscular power, fiber type distribution, and phosphocreatine (PC).

Short-Term Performances

Events lasting $10-180\,s$, primarily utilizing glycolysis and phosphocreatine ($40-90\%$ ATP) and affected by muscle and blood $H^+$ levels.

Homeostasis

The maintenance of a constant and "normal" internal environment during resting conditions.

Steady State

A physiological variable that is unchanging, but not necessarily equal to a "normal" resting value (e.g., core temperature during submaximal exercise).

Biological Control System

A series of interconnected components consisting of a sensor, control center, and effector that maintain a physical or chemical parameter at a near constant value.

Sensor

The component of a control system that detects changes in a variable.

Control Center

The component of a control system that assesses input and initiates a response.

Effector

The component of a control system that changes the internal environment back to normal.

Negative Feedback

A control mechanism where the response reverses the initial disturbance in homeostasis; most internal control systems work this way.

Positive Feedback

A biological response that increases the original stimulus (e.g., the initiation of childbirth via oxytocin release).

Gain

The degree to which a control system maintains homeostasis; systems with large gain, like pulmonary and cardiovascular systems, are more capable of maintaining stability.

Adaptation

A change in the structure and function of a cell or organ system that results in an improved ability to maintain homeostasis.

Acclimation

The environmental adaptation to stresses, such as heat stress, resulting in improved homeostatic function.

Cell Signaling

Communication between cells using chemical messengers to coordinate cellular activities and maintain homeostasis.

Intracrine Signaling

A signaling mechanism where a chemical messenger inside the cell triggers a response.

Juxtacrine Signaling

A signaling mechanism where a chemical messenger is passed between two connected cells.

Autocrine Signaling

A signaling mechanism where a chemical messenger acts on the same cell that produced it.

Paracrine Signaling

A signaling mechanism where chemical messengers act on nearby cells.

Endocrine Signaling

A signaling mechanism where chemical messengers (hormones) are released into the blood to affect cells with specific receptors in remote tissues.

Stress Proteins

Proteins, such as heat shock proteins, synthesized by cells when homeostasis is disrupted to repair damaged proteins.

Transcription

The process occurring in the myonuclei where DNA is transcribed to mRNA.

Translation

The process where mRNA is translated into protein at the ribosome.