Strand 2 Study Notes: Human Body Systems for Medical & Dental Office Technology

Levels of Organization

The hierarchical structure ranging from cells to tissues, organs, organ systems, and the entire organism.

Cells

The basic living units of the body, e.g., muscle cells and nerve cells.

Tissues

Groups of similar cells working together.

Organs

Structures made of two or more tissue types working as a unit.

Organ Systems

Groups of organs that coordinate major body functions.

Homeostasis

The body's ability to maintain stable internal conditions despite external changes.

Negative Feedback

A control mechanism that reverses a change to maintain homeostasis.

Anatomical Position

Standard reference stance: standing upright, facing forward, arms at sides with palms forward.

Superior

Towards the head.

Inferior

Towards the feet.

Anterior (ventral)

Towards the front.

Posterior (dorsal)

Towards the back.

Medial

Towards the midline.

Lateral

Away from the midline.

Proximal

Closer to the trunk or point of attachment.

Distal

Farther from the trunk or point of attachment.

Superficial

Towards the surface.

Deep

Farther from the surface.

Sagittal Plane

Divides the body into left and right.

Frontal (coronal) Plane

Divides the body into front and back.

Transverse (horizontal) Plane

Divides the body into top and bottom.

Dorsal Cavity

Includes the cranial cavity (brain) and vertebral cavity (spinal cord).

Ventral Cavity

Includes the thoracic cavity (heart, lungs) and abdominopelvic cavity (digestive, urinary, reproductive organs).

Epithelial Tissue

Covers surfaces and lines cavities and tubes.

Connective Tissue

Supports, binds, and protects; includes bone, cartilage, fat, and blood.

Muscle Tissue

Produces movement.

Nervous Tissue

Receives information, processes it, and sends signals.

Inflammation

A protective response in tissues that results in redness, heat, swelling, pain, and sometimes loss of function.

Integumentary System

Includes the skin, hair, nails, and glands; serves as a barrier and regulator of body temperature.

Epidermis

The outer layer of skin, constantly renewing itself.

Dermis

Deeper layer of skin containing blood vessels, nerves, and glands.

Mucous Membranes

Linings of the mouth and other surfaces, moist and more delicate than skin.

Skeletal System

Provides structure, protects organs, and facilitates movement.

Bone Structure

Living tissue with a strong and adaptable framework; composed of compact bone and spongy bone.

TMJ (Temporomandibular Joint)

Connects the mandible to the temporal bone of the skull, supports complex jaw movements.

Muscular System

Provides movement, posture maintenance, and heat production.

Skeletal Muscle

Voluntary muscle that moves bones.

Smooth Muscle

Involuntary muscle found in walls of organs.

Cardiac Muscle

Involuntary muscle that makes up the heart.

Nervous System

The body's rapid communication network that controls functions and processes information.

CNS (Central Nervous System)

Composed of the brain and spinal cord.

PNS (Peripheral Nervous System)

Nerves outside the CNS that link the body to the brain.

Cranial Nerves

Nerves that innervate the head and neck, controlling sensation and movement.

Endocrine System

Uses hormones to regulate long-term processes in the body.

Diabetes Mellitus

A disorder involving problems with blood glucose regulation.

Cardiovascular System

Responsible for the transport of blood, nutrients, and gases throughout the body.

Vital Signs

Indicators of health including pulse rate and blood pressure.

Lymphatic System

Maintains fluid balance and supports immune function.

Immune System

Protects against pathogens and supports defense mechanisms.

Respiratory System

Responsible for gas exchange—delivering oxygen and removing carbon dioxide.

Digestive System

Breaks down food, absorbs nutrients, and eliminates waste.

Urinary System

Removes waste and helps regulate fluid and electrolyte balance.

Reproductive System

Responsible for producing sex cells and supporting reproduction.

Salivary Glands

Produce saliva that aids in digestion and oral protection.

Dental Caries

Tooth decay resulting from acid and bacteria interactions.

Gingivitis

Inflammation of the gums, often reversible.

Periodontitis

Involves deeper tissue involvement leading to potential tooth loss.