BIOS 1600 Lecture 10- Homeostasis and Organization of the Animal Body

Homeostasis

Active maintenance of internal condition within ranges compatible with cell and organism function

Internal Environment

Fluid surroundings of the body’s cells, especially extracellular fluid, whose conditions affect cell function

Regulate Variable

Physiological quantity, such as core temperature, that a control system monitors and influences

Set Point

Reference value around which a regulated variable is maintained; can change with physiological circumstances

Normal Range

Range of values compatible with normal function under specified conditions

Thermoregulation

Processes that control body temperature by changing heat production or heat exchange

Ectotherm

Animal whose body heat comes mainly from surroundings

Endotherm

Animal whose body heat comes mainly from its own metabolism

Metabolism

Chemical reactions that sustain life, including reactions that transfer energy and release heat

Protein

Molecule made of one or more polypeptide chains that can perform structural, catalytic, transport, or signaling functions

Aging

Changes over time that can reduce physiological function and resilience

Stimulus

Detectable change in internal or external conditions that can initiate a response

Sensor/Receptor

Component that detects a condition or change and provides information to a regulatory system

Control Center

Component that integrates information and coordinates the appropriate response

Effector

Cell, tissue, or organ that carries out a response directed by a control system

Response

Change in activity produced by an effector following a signal

Negative Feedback

Response that opposes a change in the regulated variable, helps stabilize that variable

Positive Feedback

Response that reinforces an initiating change, increasing its effect until the loop is interrupted or reaches an endpoint

Feedback Loop

Regulatory arrangement in which the result of a response influences subsequent system activity

Hypothalamus

Region of the brain that that coordinates several homeostatic processes, including body temperature regulation