Form (Anatomy) Determines Function (Physiology)

Introduction to Anatomy and Physiology

Anatomy and physiology are closely related fields that form the foundation of medical science. Anatomy focuses on the structure of body parts, while physiology explores their functions and how they work together to sustain life.

• Anatomy: Study of the structure of body parts and their relationships to one another.

• Physiology: Study of the function of the body; how body parts work and carry out life-sustaining activities.

Divisions of Anatomy

Gross (Macroscopic) Anatomy

Gross anatomy examines large body structures visible to the naked eye. It is subdivided into several approaches:

• Regional Anatomy: Looks at all structures in a particular area of the body.

• System Anatomy: Focuses on one organ system (e.g., cardiovascular, nervous, muscular).

• Surface Anatomy: Studies internal structures as they relate to the overlying skin (e.g., visible muscle masses or veins).

Microscopic Anatomy

Microscopic anatomy deals with structures too small to be seen without magnification.

• Cytology: Study of cells.

• Histology: Study of tissues.

Developmental Anatomy

Developmental anatomy traces structural changes throughout the life span.

• Embryology: Study of developmental changes that occur before birth.

Levels of Structural Organization in the Human Body

Hierarchy from Atoms to Organism

The human body is organized into increasingly complex levels, each building upon the previous.

• Chemical Level: Atoms and molecules.

• Cellular Level: Cells and their organelles.

• Tissue Level: Groups of similar cells performing a common function.

• Organ Level: Contains two or more types of tissues working together.

• Organ System Level: Organs that work closely together to accomplish a common purpose.

• Organismal Level: All organ systems combined to make the whole organism.

Example: The cardiovascular system includes the heart (organ), blood vessels (organs), blood (tissue), and cells (cellular level), all working together to transport nutrients and oxygen.

The Body's Organ Systems and Their Major Functions

Overview of the 11 Organ Systems

The human body is composed of 11 organ systems, each with specific functions essential for survival.

• Integumentary System: Protects the body; includes skin, hair, and nails.

• Skeletal System: Provides support and protection; stores minerals; forms blood cells.

• Muscular System: Enables movement; maintains posture; produces heat.

• Nervous System: Fast-acting control system; responds to internal and external changes.

• Endocrine System: Secretes hormones that regulate growth, metabolism, and reproduction.

• Cardiovascular System: Transports blood, nutrients, gases, and wastes.

• Lymphatic System: Returns fluid to blood; defends against pathogens.

• Respiratory System: Supplies oxygen; removes carbon dioxide.

• Digestive System: Breaks down food; absorbs nutrients; eliminates waste.

• Urinary System: Eliminates nitrogenous wastes; regulates water and electrolyte balance.

• Reproductive System: Produces offspring.

Example: The muscular system works with the skeletal system to produce movement.

*Additional info: Expanded organ system functions for clarity and completeness.*