Introduction to Anatomy

Introduction to Anatomy

• Anatomy is the study of the structure of organisms and their parts.
• It encompasses the physical characteristics of organisms, from cells to organ systems.
• Anatomical studies can be macroscopic (examining large structures visible with the naked eye) or microscopic (using microscopes to observe tiny structures).

Levels of Organization in the Body

• Chemical level: Atoms combine to form molecules, essential for life's processes.
• Cellular level: Molecules combine to form tissues, the basic building blocks of organs.
• Tissue level: Similar cells working together to perform specific jobs define tissues.
• Organ level: Different tissues aggregate to form organs, e.g., the heart, liver.
• Organ system level: Different organs working together to accomplish a broad function as a system, e.g., the circulatory system.

Body Planes and Sections

• Anatomical position: The standard reference position for the human body, standing upright, facing forward, arms at the sides, palms forward.
• Body planes: Imaginary flat surfaces used to divide the body for study.
  • Sagittal plane: Divides the body into left and right sections.
  • Midsagittal plane: A specific sagittal plane that divides the body precisely into equal left and right halves.
  • Coronal (frontal) plane: Divides the body into anterior (front) and posterior (back) portions.
  • Transverse (horizontal) plane: Divides the body into superior (upper) and inferior (lower) portions.
• Body sections: Two-dimensional slices of the body created by cutting along one of the body planes.

Body Cavities

• Body cavities: Housed within the body are internal spaces containing organs.
  • Dorsal body cavity: Contains the cranial cavity (brain) and the vertebral cavity (spinal cord).
  • Ventral body cavity: Contains the thoracic cavity (lungs, heart) and the abdominopelvic cavity (digestive organs, reproductive organs).

Directional Terms

• Terms used to describe locations in the body.
  • Superior (cranial/cephalic): Above another structure.
  • Inferior (caudal): Below another structure.
  • Anterior (ventral): Front of the body.
  • Posterior (dorsal): Back of the body.
  • Medial: Toward the midline of the body.
  • Lateral: Away from the midline of the body.
  • Proximal: Closer to the point of attachment.
  • Distal: Farther from the point of attachment.
  • Superficial: Toward or at the body surface.
  • Deep: Away from the body surface, in lower layers.

Regional Names

• Regions of the body are named using specific terms to refer to body areas.
  • Head
  • Neck
  • Trunk (thorax, abdomen, pelvis)
  • Upper limbs (arm, forearm, hand)
  • Lower limbs (thigh, leg, foot)

Common Anatomical Structures

• Examples of major anatomical structures without going into depth include: heart, lungs, brain, spinal cord, kidneys, stomach, intestines, skeletal muscles, bones, blood vessels, and nerves.

Anatomical Variation

• The human body displays variations in structure, even within the same species.
• These differences are normal.