The Hierarchy of Structure in Animals (Unit Test)

Specialized Cells

• Specialized cells include:

  • Muscle cells

  • Bone cells

  • Blood cells

  • Sensory cells

• Specialized cells cannot survive on their own and work as part of a larger group of cells that make up the body of the animal

Organs

• Organ: a structure composed of different types of tissues working together to perform a complex body function

• Examples: Stomach, Small and large intestines, Liver, Pancreas

• Organ Systems:

  • A system of one or more organs and structures that work together to perform a vital body function

  • All organ systems obtain oxygen and nutrients and eliminate wastes

  • They all sense and respond to their environment, grow and repair damage, and reproduce

  • The task of the organ system is to perform these basic functions

  • All animals obtain oxygen and nutrients and eliminate wastes

  • They all sense and respond to their environment, grow and repair damage and reproduce

  • Organ systems assist in these basic functions

Cells and Tissues

• Cells: Simplest/basic unit of life

• Tissues: A collection of similar cells that perform a particular, but limited function.

Epithelial Tissue

Description: thin sheets of packed cells covering surfaces and lining internal organs

Function: protection from dehydration

Examples: skin, the lining of the digestive system

Connective Tissue

Description: various types of cells and fibers held together by a liquid, a solid or gel known as a matrix

Function: support, insulation

Examples: bones, tendons, blood

Muscle Tissue

Description: Bundles of long cells called muscle fibers that contain specialized proteins capable of shortening and contraction

Function: movement

Examples: heart, muscles that make bones move

Nerve Tissue

Description: Long, thin cells with branches at the ends capable of conducting electrical impulses

Function: sensory, communication with the body, coordination of body functions

Examples: brain