Anatomy and Physiology Overview

Introduction to Anatomy and Physiology

• Anatomy refers to the study of body structures and their interrelationships.
• Physiology focuses on how those body structures function.

Levels of Structural Organization

• Chemical level: Atoms combine to create molecules.
• Cellular level: Cells are formed from molecules.
• Tissue level: Similar cells group to form tissues (e.g., smooth muscle tissue).
• Organ level: Different tissues work together to form organs (e.g., heart).
• Organ system level: Various organs collaborate to perform complex functions (e.g., cardiovascular system).
• Organism level: The complete human body, composed of multiple organ systems.

Anatomical Position

• Body is erect with feet slightly apart.
• Palms face forward and thumbs point away from the body.

Directional Terms

• Help describe the locations and relationships of body parts to one another.

Body Planes

• Sagittal Plane: Divides body into right and left portions.
• Midsagittal Plane: A sagittal plane along the midline.
• Frontal (Coronal) Plane: Divides the body into anterior and posterior sections.
• Transverse (Horizontal) Plane: Divides the body into superior and inferior parts.

Body Cavities

• Dorsal Cavity: Protects the nervous system; includes cranial and vertebral cavities.
• Ventral Cavity: Houses internal organs; divided into thoracic and abdominopelvic cavities.
  • Thoracic Cavity: Contains lungs (pleural cavity) and heart (mediastinum).
  • Abdominopelvic Cavity:
    • Abdominal part includes organs like the liver and stomach.
    • Pelvic part contains bladder and reproductive organs.

Abdominal Regions and Quadrants

• Nine Abdominopelvic Regions: Used for detailed description of abdominal area.
• Four Abdominopelvic Quadrants: Right upper, left upper, right lower, left lower.

Body Regions

• Axial Region: Includes head, neck, and trunk.
• Appendicular Region: Consists of limbs or appendages.

Homeostasis

• Defined as the ability to maintain a stable internal environment amidst external changes.
• Involves regulation of chemical, thermal, and neural factors for equilibrium.
• Essential for survival and energy processing of organisms.

Homeostatic Imbalance

• Occurs when homeostasis is disrupted, potentially leading to positive feedback mechanisms that may cause disease or death.
• Example: A sudden drop in blood pressure can lead to system failure.

Summary of Key Concepts

• Anatomy: Structure and relationships of body parts.
• Physiology: Function of body systems.
• Body Planes: Sagittal, midsagittal, frontal, transverse for anatomical referencing.