Specialized cells
A multicellular organism contains different types of cells. A muscle cell and a nerve cell have different structures that help them perform different functions.
Levels of organization
Trace how specialized cells build tissues, organs and organ systems.
Class notes
Open PDF →Tissues and organs
A tissue is a group of cells and surrounding material working together. Different tissues form an organ; the heart contains muscle, connective, nervous and epithelial tissues.
Systems and organisms
Organs work together in organ systems. Systems connect with one another: circulation delivers materials that cells throughout the body need.
Explore the idea
Cell
→Tissue
→Organ
→Organ system
01Cell → tissue
A tissue is a group of cells and surrounding material working together.
02Tissue → organ
An organ contains different tissues working together.
03Organ → system
Organs cooperate in systems; multiple systems support an organism.
Explore this idea further
Watch: Levels of organization
Trace how specialized cells build tissues, organs and organ systems.
Open on YouTube →Place these in order: heart, muscle cell, circulatory system, muscle tissue.
Reveal the reasoning
Muscle cell → muscle tissue → heart → circulatory system.
Try it yourself.
Put these in order: heart, muscle tissue, circulatory system, muscle cell.
Check your thinking
Muscle cell → muscle tissue → heart → circulatory system.
Common question: Is an organ made of only one tissue?
No. An organ is made of different tissues that work together.
Take it further.
Name an organ system and describe how one of its organs helps the whole organism.
See a possible explanation
For example, the respiratory system includes the lungs, which exchange oxygen and carbon dioxide with blood.