Chapter 2 EP

Homeostasis

The maintenance of a relatively constant internal environment.

Steady State

A condition where a physiological variable is constant and unchanging but may be above normal resting values.

Negative Feedback

A biological control mechanism that restores normal values of a variable to maintain homeostasis.

Positive Feedback

A control mechanism that increases the original stimulus, leading to a larger response.

Gain of a Control System

The precision with which a control system maintains homeostasis, indicating its capability to correct disturbances.

Cell Signaling

A system of communication between cells that coordinates cellular activities to maintain homeostasis.

Intracrine Signaling

Occurs when a chemical messenger is produced inside a cell and triggers a signaling pathway within the same cell.

Juxtacrine Signaling

Cell communication through direct contact of cytoplasm between adjacent cells.

Autocrine Signaling

When a cell produces a chemical messenger that acts on itself, impacting its own function.

Paracrine Signaling

Cell signaling where chemical messengers act locally on nearby cells.

Endocrine Signaling

Chemical signals (hormones) are released into the blood and transported throughout the body.

Stress Proteins

Proteins manufactured in response to cellular stress to protect cells and restore homeostasis.

Heat Shock Proteins

A family of stress proteins that protect cells from damage due to heat and other stresses.

Acclimation

The improved function of an existing homeostatic system due to prolonged exposure to environmental stresses.

Adaptation

A change in the structure and function of a cell or organ system that enhances its ability to maintain homeostasis.