Introduction to the Human Body: Essential Notes

Anatomy and Physiology

• Anatomy: Studies the structure of the body.
• Physiology: Describes how the body functions.
• Structure and function are closely related.

Levels of Organization

• Atoms
• Molecules
• Cells
• Tissues
• Organs
• Systems
• Human organism

Major Organ Systems

• Integumentary
• Skeletal
• Muscular
• Nervous
• Endocrine
• Circulatory
• Lymphatic
• Immune
• Respiratory
• Digestive
• Urinary
• Reproductive

Homeostasis

• The body's ability to maintain a stable internal environment despite external changes.
• Maintained by homeostatic mechanisms.
• Imbalance leads to disorders.

Anatomical Position

• Standing erect, face forward.
• Arms at sides, toes and palms directed forward.

Relative Positions

• Superior and inferior
• Anterior and posterior
• Medial and lateral
• Proximal and distal
• Superficial and deep
• Central and peripheral

Planes and Sections of the Body

• Transverse plane: Divides body horizontally into upper and lower portions.
• Sagittal plane: Divides body lengthwise into right and left portions.
• Frontal plane: Divides body into anterior and posterior portions.

Cavities of the Body

• Dorsal cavity
  • Cranial cavity
  • Spinal (vertebral) cavity
• Ventral cavity
  • Thoracic cavity
    • Pleural cavities
    • Mediastinum
  • Abdominopelvic cavity
    • Divided into four quadrants and nine regions.