Introduction to Anatomy

• Anatomy is the study of the structure of living organisms
• It examines the components of the body, their organization, and their relationships

Types of Anatomy

• Gross Anatomy (Macroscopic Anatomy): Study of structures visible to the naked eye
• Microscopic Anatomy (Histology): Study of structures at the microscopic level, including cells and tissues
• Developmental Anatomy: Study of the changes in structure from conception to adulthood
• Comparative Anatomy: Study of the similarities and differences in the anatomy of different species
• Systemic Anatomy: Study of the body by systems (e.g., skeletal, muscular, nervous)
• Regional Anatomy: Study of the body by regions (e.g., head, neck, thorax)
• Radiological Anatomy: Study of anatomical structures as visualized by medical imaging techniques such as X-rays, MRI, and CT scans

Anatomical Position

• The standard reference point for anatomical descriptions
• Body is erect, feet slightly apart, arms at the sides, palms facing forward, thumbs point away from the body

Anatomical Planes

• Sagittal Plane: Divides the body into right and left parts
  • Midsagittal (Median) Plane: Divides the body into equal right and left halves
  • Parasagittal Plane: Divides the body into unequal right and left parts
• Frontal (Coronal) Plane: Divides the body into anterior (front) and posterior (back) parts
• Transverse (Horizontal) Plane: Divides the body into superior (upper) and inferior (lower) parts
• Oblique Plane: Passes through the body at an angle

Directional Terms

• Superior (Cranial): Toward the head or upper part of a structure
• Inferior (Caudal): Away from the head or toward the lower part of a structure
• Anterior (Ventral): Toward the front of the body
• Posterior (Dorsal): Toward the back of the body
• Medial: Toward the midline of the body
• Lateral: Away from the midline of the body
• Proximal: Closer to the origin of the body part or the point of attachment of a limb to the body trunk
• Distal: Farther from the origin of the body part or the 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
• Ipsilateral: On the same side of the body
• Contralateral: On opposite sides of the body

Movement Terms

• Flexion: Decreases the angle of a joint
• Extension: Increases the angle of a joint
• Abduction: Movement away from the midline
• Adduction: Movement toward the midline
• Rotation: Turning of a bone around its longitudinal axis
• Circumduction: Movement of a limb in a circular motion
• Pronation: Rotation of the forearm so that the palm faces posteriorly or inferiorly
• Supination: Rotation of the forearm so that the palm faces anteriorly or superiorly
• Inversion: Turning the sole of the foot medially
• Eversion: Turning the sole of the foot laterally
• Dorsiflexion: Lifting the foot so that its superior surface approaches the shin
• Plantar Flexion: Depressing the foot (pointing the toes)

Body Cavities

• Dorsal Body Cavity: Protects the fragile nervous system organs

  • Cranial Cavity: Contains the brain
  • Vertebral Cavity: Contains the spinal cord

• Ventral Body Cavity: Houses the internal organs (viscera)

  • Thoracic Cavity: Contains the heart and lungs
    • Pleural Cavities: Each surrounds a lung
    • Mediastinum: Contains the pericardial cavity and other thoracic organs (esophagus, trachea)
    • Pericardial Cavity: Encloses the heart
  • Abdominopelvic Cavity: Contains the abdominal and pelvic organs
    • Abdominal Cavity: Contains the stomach, intestines, liver, etc.
    • Pelvic Cavity: Contains the bladder, reproductive organs, and rectum

Serous Membranes

• Thin, double-layered membranes that cover the walls of the ventral body cavity and the outer surfaces of the organs it contains

• Parietal Serosa: Lines the body cavity walls

• Visceral Serosa: Covers the organs

  • Serous Fluid: Separates the parietal and visceral serosae; secreted by both membranes

Organ Systems

• Integumentary System: Skin, hair, nails; protects the body, regulates temperature, and provides sensory information
• Skeletal System: Bones and joints; supports the body, protects organs, and provides a framework for muscles
• Muscular System: Muscles; enables movement, maintains posture, and generates heat
• Nervous System: Brain, spinal cord, and nerves; controls and coordinates bodily functions and responses
• Endocrine System: Glands that secrete hormones; regulates growth, reproduction, and metabolism
• Cardiovascular System: Heart and blood vessels; transports blood, carrying oxygen, nutrients, and wastes
• Lymphatic System: Lymph nodes, lymphatic vessels; defends against infection and disease, returns fluids to the bloodstream
• Respiratory System: Lungs and airways; exchanges gases between the body and the environment
• Digestive System: Mouth, esophagus, stomach, intestines; breaks down food and absorbs nutrients
• Urinary System: Kidneys, bladder; filters waste from the blood and eliminates it as urine
• Reproductive System: Ovaries/testes; enables reproduction

Tissue Types

• Epithelial Tissue: Covers surfaces, lines cavities, and forms glands
• Connective Tissue: Supports, connects, and separates different types of tissues and organs in the body
• Muscular Tissue: Contracts to produce movement
• Nervous Tissue: Conducts electrical signals for communication

Skeletal System

• Bones: Provide support and protection
• Cartilage: Provides flexible support and cushioning
• Joints: Articulations between bones, enabling movement
• Ligaments: Connect bone to bone, providing stability

Muscular System

• Skeletal Muscle: Voluntary movement
• Smooth Muscle: Involuntary movement (e.g., in the digestive system)
• Cardiac Muscle: Involuntary heart contractions

Nervous System

• Brain: Control center
• Spinal Cord: Connects the brain to the body
• Nerves: Carry electrical signals throughout the body

Cardiovascular System

• Heart: Pumps blood
• Blood Vessels: Arteries, veins, and capillaries
• Blood: Transports oxygen, nutrients, and waste

Respiratory System

• Lungs: Exchange gases
• Trachea: Airway
• Bronchi: Branches of the trachea

Digestive System

• Esophagus: Carries food to the stomach
• Stomach: Digests food
• Intestines: Absorb nutrients

Urinary System

• Kidneys: Filter blood
• Bladder: Stores urine
• Ureters: tubes that carry urine from the kidneys to the bladder
• Urethra: tube that carries urine from the bladder out of the body