Levels of Organization

Learning Target: List and describe the structural levels of multicellular

organisms. (knowledge)

Use with “Human Body Organization”

Observe the diagram of the structural levels of a human. The levels of organization shown apply to all

living multicellular organisms.

Chemical Level

Inorganic molecules like H2O

Organic moleculeslike DNA

Chemicals combine to form ?Cells

Cellular Level

Cells are the basicunit of life.

Cells combine to form?

Tissues

Tissue Level

A group of similar cells that perform a common function.

For example, these cells line the mouth forming layers of protection.

Tissues combine to form?

organs

Organ Level

A group of tissues that work together to carry out a function.

For example the stomach is made of a tissue that secrets digestive juices and a tissue that churns the food.

Organs combine to form?

Organ systems

Organ System

A group of organs that work together to carry out a related function.

Example: The liver, stomach and intestines carry out digestion.

Organ systems form?Organisms

Organism

An individual living thing.

For example, a human is an organism.

Focus on Tissue

We have already learned a great deal about the chemicals and cells of living things.

Today and tomorrow we will observe cells that have combined to form tissue.

There are 4 types of tissue that make up the human body.

For each type of tissue you will learn its characteristics, location and function.

Epithelial Tissue

LocationSkin, glands, lining organs

CharacteristicsTightly packed cells

FunctionProtection, absorption and

secretion of substances

Lining of respiratory tract

This is the epithelial tissue that makes up the surface of your skin.

Connective Tissue

LocationUnder skin, surrounding

organs, blood, bonesCharacteristicsCells are spaced further

apartFunctionBinding, support,

transport

This is the connective tissue that binds your skin to the organs beneath it such as muscle.

Muscle tissue

LocationSkeletal muscles, heart,

walls of hollow organs

CharacteristicsElongated, contracts

FunctionMovement

This is muscle tissue found in skeletal muscles such as your bicep.

Nervous Tissue

LocationBrain, spinal cord, nerves

CharacteristicsTendrils

FunctionSending nerve impulses

This is the nervous tissue that would be found in your brain.