Unit 1

Anatomy and Physiology

  • Complementarity Principle

    • Function depends on structure; physiology can only be understood in the context of anatomy.

  • Variability

    • Most anatomical structures conform to standard descriptions; however, individual variations in anatomy can exist due to minor differences.

Anatomy Subdivisions

  • Gross (Macroscopic) Anatomy

    • Study of large structures visible to the naked eye (e.g., heart, lungs).

    • Approaches:

      • Regional Anatomy: Examines all structures in a specific area (e.g., abdominal anatomy).

      • Systemic Anatomy: Studies the body by systems (e.g., cardiovascular system).

      • Surface Anatomy: Examines internal structures as they correlate with overlying skin.

  • Microscopic Anatomy

    • Deals with tiny structures; includes:

      • Cytology: Study of cells.

      • Histology: Study of tissues.

  • Developmental Anatomy

    • Traces development throughout the lifespan; includes Embryology (development before birth).

  • Specialized Anatomy

    • Pathological Anatomy: Studies structural changes due to disease.

    • Radiographic Anatomy: Visualization of internal structures through imaging.

Physiology Subdivisions

  • Focuses on organ system operations (e.g., renal physiology, neurophysiology, cardiovascular physiology).

  • Physiology highlights molecular and cellular interactions vital for body functions and relies on principles of physics.

Body Organization

  • Levels of Structural Organization:

    • Chemical Level: Atoms form molecules.

    • Cellular Level: Molecules form organelles, the building blocks of cells.

    • Tissue Level: Groups of similar cells (4 types: epithelial, muscle, connective, nervous).

    • Organ Level: Structures comprising at least two tissue types performing specific functions.

    • Organ System Level: Groups of organs working together for common functions (e.g., cardiovascular system).

    • Organismal Level: The totality of all structural levels maintaining life.

Requirements for Life

  • Necessary Life Functions

    • Maintain boundaries, movement, responsiveness, digestion, metabolism, excretion, reproduction, growth.

  • Survival Needs

    • Nutrients, oxygen, water, normal body temperature, atmospheric pressure.

Homeostasis

  • Defined as the body’s ability to maintain stable internal conditions despite external changes.

  • Homeostatic Control

    • Communication via nervous and endocrine systems; regulated by receptors, control centers, and effectors.

  • Negative Feedback Mechanisms

    • Shuts off the original stimulus or reduces its intensity (e.g., regulation of body temperature).

  • Positive Feedback Mechanisms

    • Initially enhances the original stimulus (e.g., labor contractions, blood clotting).

  • Homeostatic Imbalance

    • Disturbance leads to disease; control systems can become inefficient with age.

Anatomical Terms

  • Anatomical Position: Body stands erect, feet apart, palms forward, thumbs out.

  • Directional Terms: Help describe relative positions of structures (e.g., lateral, medial).

  • Body Planes:

    • Sagittal Plane: Divides body into right and left parts.

    • Frontal Plane: Divides body into anterior and posterior parts.

    • Transverse Plane: Divides body into superior and inferior parts.

Body Cavities

  • Dorsal Cavity:

    • Cranial Cavity: Houses the brain.

    • Vertebral Cavity: Encloses the spinal cord.

  • Ventral Cavity:

    • Thoracic Cavity: Contains lungs and heart, divided into pleural cavities and mediastinum.

    • Abdominopelvic Cavity: Contains abdominal organs and pelvic organs.

  • Serous Membranes: Cover organs and reduce friction (e.g., pericardial, pleural cavities).

  • Abdominopelvic Regions: Four quadrants (RUQ, LUQ, RLQ, LLQ) or Nine Regions (epigastric, umbilical, hypogastric, etc.) for organ location.