Chapter 1 The Human Body: An Orientation

Vocabulary flashcards covering foundational concepts of human anatomy, physiology, body systems, anatomical terminology, body cavities, and homeostasis from Chapter 1.

Anatomy

The study of the structure and shape of the body and its parts, using observation to see sizes and relationships of parts.

Gross Anatomy

The study of large, easily observable body structures, such as digestive system organs.

Microscopic Anatomy

The study of body structures that are too small to be seen with the naked eye, where cells and tissues can be viewed only with a microscope.

Physiology

The study of how the body and its parts work or function.

Levels of Structural Organization

The six structural levels comprising the human body: atoms, cells, tissues, organs, organ systems, and organisms.

Integumentary System

The external body covering composed of skin, hair, and fingernails that waterproofs the body, cushions and protects deeper tissue, produces vitamin D, excretes salts, regulates temperature, and houses cutaneous nerve receptors.

Skeletal System

An organ system consisting of bones, cartilages, ligaments, and joints that provides muscle attachment for movement, protects vital organs, forms blood cells, and stores minerals.

Muscular System

An organ system consisting of skeletal muscles that contract (or shorten) to produce movement of bones.

Nervous System

A fast-acting control system consisting of the brain, spinal cord, nerves, and sensory receptors that responds to internal and external stimuli by detecting changes, assessing information in the central nervous system, and activating effectors.

Endocrine System

An organ system composed of glands (such as the pituitary, thyroid, parathyroids, adrenals, thymus, pancreas, pineal, ovaries, and testes) that secrete hormones into the blood to control growth, reproduction, and nutrient use.

Cardiovascular System

An organ system consisting of the heart and blood vessels that transports blood carrying oxygen, carbon dioxide, nutrients, hormones, and protective white blood cells throughout the body.

Lymphatic System

An organ system consisting of lymphatic vessels, lymph nodes, and lymphoid organs that returns leaked fluids to the bloodstream, cleanses the blood, and houses white blood cells involved in immunity.

Respiratory System

An organ system including nasal passages, pharynx, larynx, trachea, bronchi, and lungs that supplies the body with oxygen and removes carbon dioxide via gas exchange across the air sacs of the lungs.

Digestive System

An organ system consisting of the oral cavity, esophagus, stomach, small and large intestines, rectum, and accessory organs that breaks down food, allows nutrient absorption into blood, and eliminates indigestible material as feces.

Urinary System

An organ system composed of kidneys, ureters, urinary bladder, and urethra that eliminates nitrogenous wastes, maintains acid-base balance, regulates water and electrolyte balance, and helps regulate blood pressure.

Metabolism

All chemical reactions within the body that break down complex molecules into smaller ones, build larger molecules from smaller ones, and produce energy ($\text{ATP}$) under the regulation of hormones.

Excretion

The necessary life function of eliminating excreta (waste) produced by metabolic reactions via urine, feces, or sweat.

Normal Body Temperature

$37^{\circ}\text{C}$ ($98.6^{\circ}\text{F}$); a survival need where dropping below slows or stops chemical reactions and rising above causes reactions to proceed too rapidly.

Anatomical Position

The standard body position reference point where the body stands erect with feet parallel, arms hanging at the sides, palms facing forward, and thumbs pointing away from the body.

Superior (Cranial or Cephalic)

Toward the head or upper part of a structure or the body; above.

Inferior (Caudal)

Away from the head or toward the lower part of a structure or the body; below.

Anterior (Ventral)

Toward or at the front of the body; in front of.

Posterior (Dorsal)

Toward or at the backside of the body; behind.

Medial

Toward or at the midline of the body; on the inner side of.

Lateral

Away from the midline of the body; on the outer side of.

Intermediate

Between a more medial and a more lateral structure.

Proximal

Close to the origin of the body part or point of attachment of a limb to the body trunk.

Distal

Farther from the origin of a body part or point of attachment of a limb to the body trunk.

Superficial (External)

Toward or at the body surface.

Deep (Internal)

Away from the body surface; more internal.

Sagittal Section

A cut along an imaginary line that divides the body or organ into left and right parts.

Median (Midsagittal) Section

A cut along an imaginary line that divides the body or organ into equal left and right parts.

Frontal (Coronal) Section

A cut along an imaginary line that divides the body or organ into anterior and posterior parts.

Transverse (Cross) Section

A cut along an imaginary line that divides the body or organ into superior and inferior parts.

Dorsal Body Cavity

An internal body cavity subdivided into the cranial cavity (housing the brain and protected by the skull) and the spinal cavity (housing the spinal cord and protected by vertebrae).

Ventral Body Cavity

An internal body cavity divided by the diaphragm into the superior thoracic cavity and the inferior abdominopelvic cavity.

Mediastinum

The central region of the thoracic cavity that houses the heart, trachea, and other organs.

Homeostasis

The maintenance of relatively stable internal conditions; a dynamic state of equilibrium or balance necessary for normal body functioning and life.

Receptor

A sensor that responds to changes in the environment (stimuli) and sends information to the control center along an afferent pathway.

Control Center

The component of a homeostatic control mechanism that determines the set point, analyzes incoming information, and determines the appropriate response.

Effector

The component of a homeostatic control mechanism that receives information from the control center along an efferent pathway and provides the means for the response.

Negative Feedback

The most common homeostatic control mechanism that works like a household thermostat by shutting off the original stimulus or reducing its intensity.

Positive Feedback

A rare homeostatic mechanism that increases the original stimulus to push the variable farther at an accelerating rate, occurring in blood clotting and childbirth.