LEVELS OF STRUCTURAL ORGANIZATION 7.L.3B.1 Develop and use models to explain how the structural organizations within multicellular organisms function to serve the needs of the organism.

The Human Body- Organism Hierarchy Is divided into specific levels of organization Makes the human body a complex organism FROM SIMPLEST TO MOST COMPLEX CELLS – TISSUES – ORGAN – ORGAN SYSTEMS

Cells Basic units of structure and function in the body Even though all cells perform the processes that keep us alive, they also have SPECIALIZED FUNCTIONS Examples: Nerve cells (neurons) Blood cells Bone cells

Tissues A group of specialized cells that work together to perform the same function 4 types of tissues: Nerve (nervous) tissue Muscle tissue Epithelial (skin) tissue Connective tissue

Nerve tissue Carries impulses back and forth from the brain to the body

Muscle tissue contracts and shortens, making body parts move Cardiac Smooth Skeletal

Epithelial tissue covers the surfaces of the body Inside, as lining and/or covering of internal organs Outside, as layer of skin

Connective tissue Connects all parts of the body and provides support Tendons Ligaments Cartilage

A group of two or more different types of tissue that work together to perform a specific function. more complex tasks than the tissue EXAMPLE: the heart is made of muscle and connective tissues which function to pump blood throughout the body. Roots and stems are organs for the flower. Organs

Organ Systems A group of two or more organs that work together to perform a specific function Each organ system has its own function but the systems work together and depend on one another. Example: Plants and animals have reproductive systems

Organ Systems ELEVEN organ systems Circulatory Muscular Digestive Nervous Endocrine Reproductive Excretory (urinary) Respiratory Immune Skeletal integumentary (skin)