INTRODUCTION TO THE HUMAN BODY

  • The human body is a complex structure composed of millions of microscopic parts that work in coordination.
  • Lifespan: Approximately 75 years of normal bodily function.
  • Curiosity about bodily functions and pathologies leads to studying anatomy and physiology.

ANATOMY AND PHYSIOLOGY: DEFINITIONS AND SCOPE

  • Anatomy (ah-NAT-o-mee): The study of body structure.

    • Focus includes the heart’s appearance, size, composition, organization, and location.
    • Originates from the Greek word for "dissect".
    • Historical methods involved dissection of bodies, often illegally obtained.

  • Physiology (fiz-ee-OL-o-jee): The study of body functions.

    • Explains bodily processes, such as how the heart pumps blood and its significance for life.

  • Pathophysiology (path-o-fiz-ee-OL-o-jee): Studies the effects of diseases on body function and the processes during disorders, e.g., understanding heart attacks.

OBJECTIVES OF STUDYING ANATOMY AND PHYSIOLOGY

  1. Define anatomy and physiology.
  2. List the levels of organization of the human body.
  3. Describe the 12 major organ systems.
  4. Define homeostasis.
  5. Describe the anatomical position.
  6. List common terms used for relative body positions.
  7. Describe the three major planes of the body.
  8. List anatomical terms for body quadrants and regions.
  9. Describe the major cavities of the body.

KEY TERMS (Partial List)

  • Abdominopelvic cavity: Contains digestive and reproductive organs.
  • Anatomical position: Standard body posture used as a reference.
  • Cavities: Spaces within the body that house organs.
  • Homeostasis: Maintenance of a stable internal environment.

LEVELS OF ORGANIZATION

  • The human body is organized hierarchically from simple to complex:
    • Atoms → Molecules → Cells → Tissues → Organs → Organ Systems → Human Organism.
  • For example:
    • Atoms (H, O, C) form molecules (H2O, glucose), which form cells (muscle cells), leading to tissues (muscle tissue) and so forth.

MAJOR ORGAN SYSTEMS

  1. Integumentary System: Skin, hair, nails; regulates temperature, sensation.
  2. Skeletal System: Bones, joints; supports and protects body organs, facilitates movement.
  3. Muscular System: Skeletal, cardiac, and smooth muscle; enables movement and posture maintenance.
  4. Nervous System: Brain, spinal cord, nerves; processes sensory information and coordinates responses.
  5. Endocrine System: Glands that secrete hormones regulating bodily functions.
  6. Circulatory System: Heart, blood, blood vessels; transports nutrients and waste.
  7. Lymphatic System: Lymph nodes, vessels; protects against pathogens.
  8. Immune System: Protects body from infection.
  9. Respiratory System: Lungs and airways; facilitates gas exchange.
  10. Digestive System: Organs involved in food processing and absorption.
  11. Urinary System: Kidneys, bladder; removes waste and regulates body fluids.
  12. Reproductive System: Organs involved in producing offspring.

HOMEOSTASIS

  • Homeostasis (ho-me-o-STAY-sis) refers to the body's ability to maintain a stable internal environment despite external changes.
  • In a healthy individual, body temperature is maintained (98.6°F or 37°C) regardless of external conditions.

ANATOMICAL POSITION AND TERMINOLOGY

  • Anatomical Position: Body is upright, face forward, arms at sides, palms facing forward.
  • Relative Positions:
    • Superior: Above another part (head vs. chest).
    • Inferior: Below another part (chest vs. head).
    • Anterior: Front (heart anterior to spine).
    • Posterior: Back (spine posterior to heart).
    • Medial: Closer to midline (nose medial to ears).
    • Lateral: Away from midline (ears lateral to nose).
    • Proximal: Closer to point of attachment (elbow proximal to wrist).
    • Distal: Farther from point of attachment (fingers distal to wrist).
    • Superficial: Near surface (skin superficial to muscles).
    • Deep: Away from surface (bones deep to skin).

PLANES OF THE BODY

  1. Sagittal Plane: Divides body into right and left.
  2. Frontal (Coronal) Plane: Divides body into anterior and posterior.
  3. Transverse Plane: Divides body into superior and inferior.

REGIONAL TERMS

  • Specific names for body regions:
    • Abdominal, Cervical, Buccal, Gluteal, amongst others.

CAVITIES OF THE BODY

  1. Dorsal Cavity: Composes of the cranial (brain housing) and spinal (spinal cord housing) cavities.
  2. Ventral Cavity: Contains the thoracic cavity (heart and lungs) and abdominopelvic cavity (digestive and reproductive organs).
  3. Abdominopelvic Cavity: Can be further divided into quadrants (RUQ, LUQ, RLQ, LLQ) and regions (epigastric, umbilical, hypogastric).

MEDICAL TERMINOLOGY AND DISORDERS

  • Cytology: Study of cells, crucial for understanding diseases.
  • Glycolysis: Breakdown of glucose.
  • Gluconeogenesis: Formation of glucose from non-glucose sources.
  • Pathogens: Microorganisms causing diseases; include bacteria, viruses, fungi, and protozoa.