Introduction to Anatomy & Physiology: Terminology, Organization, and Body Systems

Introduction to Anatomy & Physiology

Basic Terminology and Definitions

Anatomy and physiology are foundational sciences in understanding the human body. Anatomy refers to the study of body structure, while physiology focuses on body function. Mastery of anatomical terminology is essential for clear communication in health sciences.

• Anatomy: Study of the structure of body parts and their relationships.

• Physiology: Study of the function of body parts and systems.

Levels of Organization

The human body is organized in a hierarchical manner, from the smallest chemical units to the complete organism.

• Atom → Molecule → Cell → Tissue → Organ → Organ System → Organism

• Example: Oxygen atom → Water molecule → Muscle cell → Muscle tissue → Heart → Cardiovascular system → Human body

Macromolecules

Macromolecules are large, complex molecules essential for life.

• Proteins: Structural and functional molecules (e.g., enzymes, hemoglobin)

• Lipids: Energy storage, cell membranes (e.g., fats, phospholipids)

• Carbohydrates: Energy source, cell structure (e.g., glucose, starch)

• Nucleic acids: Genetic information (e.g., DNA, RNA)

Body Regions and Anatomical Terminology

Common and Proper Anatomical Terms

Precise terminology is used to describe body regions, structures, and directions. The following table summarizes common names, proper anatomical names, and their corresponding adjectives.

Common Name	Proper Name (Noun)	Corresponding Region (Adj.)
Head	Cephalon	Cephalic
Forehead	Frons	Frontal
Skull	Cranium	Cranial
Eye	Oculus	Ocular
Ear	Auris	Otic
Nose	Nasus	Nasal
Mouth	Oris	Oral
Cheek	Bucca	Buccal
Face	Facies	Facial
Chin	Mentis	Mental
Neck	Cervicus	Cervical
Breastbone	Sternum	Sternal
Breast	Mamma	Mammary
Chest	Thorax	Thoracic
Shoulder	Acromion	Acromial
Upper Arm	Brachium	Brachial
Forearm	Antebrachium	Antebrachial
Elbow (anterior)	Antecubitis	Antecubital
Elbow (posterior)	Olecranon	Olecranal
Wrist	Carpus	Carpal
Hand	Manus	Manual
Fingers	Digit / Phalange	Digital / Phalangeal
Palm	Palma	Palmar
Thumb	Pollex	Pollecal
Armpit	Axilla	Axillary
Back	Dorsum	Dorsal
Lower back	Lumbus	Lumbar
Stomach	Abdomen	Abdominal
Navel	Umbilicus	Umbilical
Buttock	Gluteus	Gluteal
Region between anus/genitalia	Perineum	Perineal
Groin	Inguen	Inguinal
Genital Area	Pubis	Pubic
Hip	---	Coxal
Posterior between hips	Sacrum	Sacral
Lower Leg	Crus	Crural
Knee (anterior)	Patella	Patellar
Knee (posterior)	Popliteus	Popliteal
Thigh	Femur	Femoral
Side of leg	---	Fibular
Calf	Sura	Sural
Heel of foot	Calcaneus	Calcaneal
Sole of foot	Planta	Plantar
Ankle	Tarsus	Tarsal
Foot	Pes	Pedal
Toes	Digits	Digital region
Great Toe	Hallux	Hallual

Additional info: Some entries for 'Hip' and 'Side of leg' lack proper noun forms in the original; 'Coxal' and 'Fibular' are the correct adjectives.

Directional Terms

Directional terms are used to describe the locations of structures relative to other structures or locations in the body.

• Anterior: Front of body

• Posterior/Dorsal: Back of body

• Ventral: Belly side

• Cranial/Cephalic: Head

• Superior: Above, towards head

• Inferior: Below, away from head

• Medial: Toward the center

• Lateral: Away from center

• Proximal: Towards the point of origin on a limb

• Distal: Away from point of origin

• Superficial: Close to body surface

• Deep: Away from body surface

• Caudal: Toward the tail

Body Planes and Sections

Body planes are imaginary lines used to divide the body into sections for anatomical study.

• Sagittal: Divides body into left and right parts

• Midsagittal: Divides body into equal right and left halves

• Parasagittal: Parallel to sagittal plane, unequal halves

• Transverse/Horizontal/Cross: Divides body into top and bottom

• Frontal/Coronal: Separates anterior and posterior portions

• Oblique: Diagonal division (not parallel to any standard plane)

• Ipsilateral: Same side

• Contralateral: Opposite side

Additional info: 'Coronal' is most often used in reference to the skull.

Anatomical Position

The anatomical position is a standard reference for describing locations and directions on the human body.

• Body erect

• Feet flat, shoulder width apart

• Arms at sides

• Palms facing anteriorly

Body Cavities and Subdivisions

Major Body Cavities

The body contains several major cavities that house organs and structures.

• Ventral Cavity:

  • Thoracic cavity: Contains right and left pleural cavities (lungs), pericardial cavity (heart)

  • Mediastinum: Central space between lungs, contains heart, trachea, esophagus (not a true cavity)

  • Abdominopelvic cavity: Contains digestive organs, pelvic bladder, reproductive organs

• Dorsal Cavity:

  • Cranial cavity: Contains the brain

  • Vertebral cavity: Contains the spinal cord

Taxonomy of Humans

Classification and Characteristics

Humans are classified in biological taxonomy based on shared characteristics.

Order	Human Order	Characteristics
Kingdom	Animalia	Eukaryotic, heterotrophic, animal cells
Phylum	Chordata	Dorsal, hollow nerve cord, pharyngeal pouches
Subphylum	Vertebrata	Segmented vertebral column
Class	Mammalia	Mammary glands and hair
Order	Primata	Well-developed brain, prehensile hands
Family	Hominidae	Large cerebrum, bipedal locomotion
Genus	Homo	Flattened face
Species	Sapien	Largest cerebrum

Organ Systems of the Human Body

The 11 Major Organ Systems

The human body is composed of 11 major organ systems, each with specific structures and functions. The mnemonic CDR SMILE RUN can help recall them.

• Cardiovascular: Heart, blood vessels; transports nutrients and gases

• Digestive: Stomach, intestines; processes food and absorbs nutrients

• Reproductive: Ovaries, testes; produces offspring

• Skeletal: Bones, cartilage; supports and protects body

• Muscular: Muscles; movement and heat production

• Integumentary: Skin, hair, nails; protection and temperature regulation

• Lymphatic: Lymph nodes, vessels; immune response and fluid balance

• Endocrine: Glands; hormone production and regulation

• Respiratory: Lungs, airways; gas exchange

• Urinary: Kidneys, bladder; removes waste and regulates water balance

• Nervous: Brain, spinal cord, nerves; controls body activities and processes information

Branches of Anatomy and Physiology

There are several specialized branches within anatomy and physiology, each focusing on specific aspects of the body.

• Cardiovascular: Study of heart and blood vessels

• Comparative: Comparison of different species

• Cytology/Cellular Physiology: Study of cells

• Developmental: Study of organism growth and development

• Endocrinology: Study of hormones and glands

• Gross Anatomy: Structures visible to the naked eye

• Histology: Study of tissues

• Immunology: Study of immune system

• Neurology: Study of nervous system

• Renal: Study of kidneys

• Surface Anatomy: Study of external features

• Systemic Anatomy: Study of organ systems

• Altitude Physiology: Effects of altitude on body

• Exercise Physiology: Effects of exercise on body

• Medical Physiology: Application to medicine

• Reproductive Physiology: Study of reproductive organs and processes