Anatomy and Physiology: Key Concepts and Homeostasis Principles

Anatomy

The science of the structure of living organisms.

Physiology

The science of the functioning of living organisms.

Atom

The smallest part of an element; indivisible by ordinary chemical means.

Cells

The basic biological unit of living organisms, enclosed by a limiting membrane; cells in more complex organisms contain a nucleus and a variety of organelles.

Tissues

A group of similar cells specialized to perform a specific function; primary tissue types are epithelial, connective, muscle, and nervous tissues.

Organ

A part of a body formed of 2 or more tissues that perform a specialized function.

Organ System

A group of organs that work together to perform a vital organ function.

Organism

Represents the highest level of structural organization; the living human being.

Movement

Includes all the activities promoted by the muscular system, such as propelling ourselves from one place to another.

Responsiveness

The ability to sense changes (stimuli) in the environment and react to them.

Digestion

The process of breaking down ingested food into simple molecules that can then be absorbed into the blood.

Metabolism

A broad term that refers to all chemical reactions that occur within the body and all its cells.

Excretion

The process of removing waste from the body.

Reproduction

The production of offspring, which can occur on a cellular or organismal level.

Nutrients

Chemical substances taken through food for energy and cell building.

Anatomical Position

A standard reference position where the body is erect with the feet parallel and arms at sides with palms forward.

Directional Terms

Terms that allow medical personnel and anatomists to explain exactly where one body part is in relation to another.

Plane

An imaginary flat surface through which the body or organ is divided into sections.

Diaphragm

A dome shaped muscle that separates the superior thoracic cavity from the rest of the ventral cavity.

Homeostasis

The body's ability to maintain relatively stable internal conditions.

Receptor

A type of sensor that monitors and responds to changes in the environment by sending information to the control center.

Control Center

Component that determines the level ('set point') at which a variable is to be maintained, analyzes the info it receives, and determines an appropriate response.

Effector

Component that provides the means for the control center's output to the stimulus.

Negative Feedback

Mechanisms where the net effect of the response to the stimulus is to either shut off the original stimulus or reduce its intensity.

Positive Feedback

Mechanisms that tend to increase the original disturbance and push variable farther from original value.

Homeostatic Imbalance

A condition resulting from the disturbance of homeostasis, leading to disease or aging.