Structural organization of the human body

Introduction

The human body is organized into six levels: chemical, cellular, tissue, organ, organ system and organism levels. The chemical level includes atoms and molecules, which form organelles at the cellular level. Cells that look similar and perform the same functions form a tissue.

There are four important tissue types in the body, each with a specific group of functions:

• Epithelial tissue: protection, secretion, absorption
• Connective tissue: support, movement, shock absorption, transport of nutrients
• Muscle tissue: locomotion, contraction of the heart, peristalsis
• Nervous tissue: communication, control and co-ordination

Two or more tissue types can combine forming an organ, and organs work with each other to form organ systems.

The human body can be divided into eleven functional organ systems. These include the integumentary, skeletal, muscular, nervous, endocrine, respiratory, cardiovascular, lymphatic, digestive, urinary and reproductive systems. All these systems interact and function together to form a living organism.

Explore concepts

Levels of organization

Learn the six levels of organization with an example in this illustration.

Types of tissues

There are four important tissue types in humans. Learn about their locations in the body with this image.

Organ systems

There are eleven organ systems. Explore some of their important functions with this illustration!

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Level up your knowledge of the structural organization of the body with this quiz!

Summary