Overview of Human Anatomy
Human anatomy is the scientific study of the structure of the human body. It forms the foundation of medical practice and is typically divided into two main areas:
- Gross (Macroscopic) Anatomy – the study of body parts visible to the naked eye.
- Microscopic Anatomy – the study of structures that require magnification, including cells and tissues (also known as histology).
Major Systems of the Human Body
- Skeletal System
- Composed of bones, cartilage, and joints.
- Provides structure, protection for organs, and anchors for muscles.
- Muscular System
- Includes skeletal, smooth, and cardiac muscles.
- Enables movement, posture, and heat production.
- Nervous System
- Comprises the brain, spinal cord, and nerves.
- Controls body activities through electrical impulses and coordinates responses to stimuli.
- Endocrine System
- Glands like the thyroid, pancreas, and adrenal glands.
- Regulates body functions through hormones.
- Cardiovascular System
- Includes the heart and blood vessels.
- Transports oxygen, nutrients, and waste throughout the body.
- Respiratory System
- Consists of lungs, trachea, and other structures.
- Facilitates gas exchange—oxygen in, carbon dioxide out.
- Digestive System
- Organs such as the mouth, stomach, intestines, and liver.
- Breaks down food for energy and nutrient absorption.
- Urinary System
- Includes kidneys, ureters, bladder, and urethra.
- Removes waste and maintains fluid and electrolyte balance.
- Reproductive System
- Male and female organs responsible for producing offspring.
- Lymphatic/Immune System
- Includes lymph nodes, spleen, and immune cells.
- Defends the body against infections and maintains fluid balance.
- Integumentary System
- Made up of the skin, hair, nails, and glands.
- Protects the body and helps regulate temperature.
Levels of Organization in the Body
- Chemical Level – Atoms and molecules (e.g., DNA, proteins)
- Cellular Level – Basic structural and functional units of life
- Tissue Level – Groups of similar cells performing a function
- Organ Level – Structures composed of two or more tissue types
- Organ System Level – Organs working together for a common purpose
- Organism Level – A complete living being