Introduction to the Human Body

Vocabulary terms covering anatomy and physiology basics, body systems, structural organization, directional terms, planes, regional areas, body cavities, and medical terminology basics.

Anatomy

The branch of science that studies the structure of the body; the word comes from the Greek word meaning to dissect.

Physiology

The branch of science that describes how the body functions.

Pathophysiology

The branch of science that describes the consequences of the improper functioning of the body, such as during a disease or heart attack.

Cells

The basic unit of life, formed from organized molecules.

Tissues

Specialized groups of cells that work together.

Organs

Structures such as the heart, stomach, and kidney that are composed of arranged tissues.

Organ Systems

Groups of organs that create a system with a specific function, such as digestion, excretion, or reproduction.

Integumentary System

Consists of the skin, hair, and nails; it forms a covering, regulates body temperature, and contains structures for sensation.

Skeletal System

The basic framework of the body consisting of bones, joints, and cartilage; it protects and supports organs, enables movement, and produces most blood cells.

Muscular System

Composed of skeletal muscles (skeleton movement), cardiac muscles (pumping blood), and smooth muscles (moving body fluid).

Nervous System

Made of the brain, spinal cord, nerves, and sense organs; it receives environmental information, interprets it, and transmits decisions.

Endocrine System

Contains glands that secrete hormones to regulate growth, reproduction, metabolism, and water balance.

Circulatory System

Consists of the blood, heart, and blood vessels; it transports nutrients and oxygen to cells and carries waste away.

Lymphatic System

Includes lymph nodes, lymphatic vessels, and lymph; plays a role in fluid balance and defense against pathogens.

Immune System

An elaborate defense system protecting the body from pathogens, allergens, and abnormal cells like cancer.

Respiratory System

Contains the lungs and air conductors; responsible for oxygen intake, carbon dioxide removal, and acid-base balance regulation.

Digestive System

Organs designed to ingest food, break it down for absorption, and eliminate unabsorbed waste.

Urinary System

Contains kidneys and other structures to excrete waste via urine and control water, electrolyte, and acid-base balance.

Reproductive System

Made of organs and structures that enable humans to reproduce.

Homeostasis

The body's ability to maintain a stable internal environment, such as a body temperature of approximately $98.6^{\circ}\text{F}$ ($37^{\circ}\text{C}$), in response to a changing environment.

Anatomical Position

The body is standing erect, face forward, arms at the sides, with toes and palms of the hands directed forward.

Superior

A part is above another part or is closer to the head.

Inferior

A part is located below another part or is closer to the feet.

Anterior

Toward the front surface (the belly surface); also called ventral.

Posterior

Toward the back surface; also called dorsal.

Medial

Toward the midline of the body.

Lateral

Away from the midline of the body.

Proximal

Nearer to the point of attachment, often the trunk of the body.

Distal

Farther away from the point of attachment than another part.

Superficial

Located on or near the surface of the body.

Deep

Away from the surface of the body.

Central

Located in the center.

Peripheral

Away from the center and extending toward the limbs.

Sagittal Plane

Divides the body lengthwise into right and left portions.

Frontal Plane

Divides the body into anterior (ventral) and posterior (dorsal) portions; also called the coronal plane.

Transverse Plane

Divides the body horizontally, creating an upper (superior) and a lower (inferior) body; also called a cross section.

Abdominal (anterior region)

Anterior trunk just below the ribs.

Antecubital

The area in front of the elbow.

Axillary

The armpit.

Brachia!

The arm.

Buccal

The cheek area; the cavity between the gum and cheek.

Cervical

The neck region.

Digital

Fingers or toes.

Femoral

The thigh area.

Inguinal

The area where the thigh meets the trunk of the body; often called the groin.

Patellar

The front of the knee over the kneecap.

Caudal

Near to the lower region of the spinal column, near the tailbone.

Popliteal

Behind, or back of, the knee area.

Viscera

The organs located within the cavities of the body.

Dorsal Cavity

Located toward the back of the body; divided into the cranial and spinal (vertebral) cavities.

Cranial Cavity

Located within the skull and contains the brain.

Ventral Cavity

Located toward the front of the body; divided into the thoracic and abdominopelvic cavities.

Mediastinum

A space in the thoracic cavity that contains the heart, thymus gland, parts of the esophagus, trachea, and large blood vessels.

Pleural Cavities

Left and right compartments within the thoracic cavity that contain the lungs.

Abdominopelvic Cavity

Located below the diaphragm; contains the abdominal and pelvic cavities.

Epigastric Region

The upper central region of the abdominopelvic cavity, located below the breastbone.

Hypogastric Region

The lower central region located just below the umbilical region.

Hypochondriac Regions

Right and left regions located on either side of the epigastric region, overlying the lower ribs.

Word Root

The core of a medical word that provides the basic meaning or subject.

Suffix

A word part attached to the end of a word root to modify its meaning, such as -itis meaning inflammation.

Prefix

A word part attached to the beginning of a word root to modify its meaning, such as mal- meaning poor or bad.