1. Anatomy
Anatomy is the study of the structure of the human body — what it’s made of and how the parts are organized.
It focuses on the form of body parts: their names, locations, and relationships to each other.
Major Branches of Anatomy:
Gross (Macroscopic) Anatomy: Structures visible to the naked eye (e.g., organs, muscles, bones).
Microscopic Anatomy: Structures only seen with a microscope, such as cells and tissues.
Histology – study of tissues.
Cytology – study of cells.
Developmental Anatomy: How structures form and change over a lifetime (e.g., embryology).
Regional & Systemic Anatomy: Studying the body by regions (head, chest, etc.) or systems (skeletal, muscular, etc.).
Example:
The heart has four chambers, valves, and blood vessels entering and leaving it — that’s anatomy.
2. Physiology
Physiology is the study of how the body works — the functions of cells, tissues, and organs, and how they interact to sustain life.
It focuses on processes like:
How muscles contract
How the heart pumps blood
How the lungs exchange gases
How the nervous system controls movement
Branches of Physiology:
Cell Physiology: How cells function.
Systemic Physiology: How organ systems work (e.g., cardiovascular, respiratory, digestive).
Pathophysiology: How diseases affect body function.
Example:
How the heart contracts to pump blood through the body — that’s physiology.
3. Relationship Between Anatomy and Physiology
These two sciences are deeply connected.
Structure determines function.
For example:
The structure of red blood cells (small, flexible, concave shape) allows them to function by moving easily through blood vessels and carrying oxygen efficiently.
The structure of the heart’s valves ensures one-way blood flow.
4. Levels of Organization in the Human Body
From simplest to most complex:
Chemical level: Atoms and molecules
Cellular level: Cells are the basic unit of life
Tissue level: Groups of similar cells working together
Organ level: Two or more tissues forming a functional unit
Organ system level: Groups of organs working together
Organism level: The entire human body