Introduction to Anatomy

• Anatomy is the study of the structure of living organisms.

Levels of Organization

• Anatomy explores the organization of the body from the simplest to the most complex levels.
• Chemical Level: Atoms combine to form molecules.
• Cellular Level: Molecules form organelles, such as the nucleus and mitochondria, which make up cells.
• Tissue Level: Similar cells and surrounding materials make up tissues.
• Organ Level: Different tissues combine to form organs, such as the heart and stomach.
• System Level: Organs are organized into systems, such as the digestive system and cardiovascular system.
• Organismal Level: All the systems of the body work together to maintain life.

Anatomical Position

• The anatomical position is a standard reference point for anatomical descriptions.
• Body is erect, feet slightly apart, palms facing forward, and thumbs point away from the body.

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.

Regional Terms

• Axial Region: Includes the head, neck, and trunk.
• Appendicular Region: Includes the limbs (arms and legs).
• Specific regional terms:
  • Cephalic (head)
  • Cervical (neck)
  • Thoracic (chest)
  • Abdominal (abdomen)
  • Pelvic (pelvis)
  • Upper limb (arm, forearm, wrist, hand)
  • Lower limb (thigh, leg, ankle, foot)

Body Planes

• Sagittal Plane: Divides the body into right and left parts.
  • Midsagittal (median) plane: Sagittal plane that lies exactly in the midline.
  • Parasagittal plane: All other sagittal planes offset from the midline.
• Frontal (coronal) Plane: Divides the body into anterior and posterior parts.
• Transverse (horizontal) Plane: Divides the body into superior and inferior parts.
• Oblique Section: Cuts made diagonally.

Body Cavities

• Dorsal Body Cavity: Protects the fragile nervous system organs.
  • Cranial Cavity: Encases the brain.
  • Vertebral Cavity: Encases the spinal cord.
• Ventral Body Cavity: Houses the internal organs (viscera).
  • Thoracic Cavity:
    • Pleural cavities: Each houses a lung.
    • Mediastinum: Contains the pericardial cavity, and surrounds the remaining thoracic organs (esophagus, trachea).
    • Pericardial cavity: Encloses the heart.
  • Abdominopelvic Cavity:
    • Abdominal cavity: Contains the digestive organs, kidneys.
    • Pelvic cavity: Contains the urinary bladder, reproductive organs, and rectum.

Serous Membranes

• Parietal serosa: Lines the internal body cavity walls.
• Visceral serosa: Covers the internal organs.
• Serous fluid: Separates the serosae.

Abdominopelvic Regions and Quadrants

• Quadrants: The abdominopelvic area is divided into four quadrants.
  • Right Upper Quadrant (RUQ)
  • Left Upper Quadrant (LUQ)
  • Right Lower Quadrant (RLQ)
  • Left Lower Quadrant (LLQ)
• Regions: The abdominopelvic area can be divided into nine regions.
  • Right hypochondriac region
  • Epigastric region
  • Left hypochondriac region
  • Right lumbar region
  • Umbilical region
  • Left lumbar region
  • Right iliac (inguinal) region
  • Hypogastric (pubic) region
  • Left iliac (inguinal) region

Explore the basics of anatomy, including levels of organization from chemical to organismal. Learn about the anatomical position and directional terms like superior and inferior. Understand how the body is structured and how its systems work together.