Levels of Organization in the Human Body
Organ Systems
A group of two or more organs working together for a specific job. ex. skeletal, muscular, circulatory, respiratory, excretory, nervous, digestive, reproductive
Cell
Basic unit of life that all organisms are made of.
Levels of Organization in the Human Body
Cells > Tissues > Organs > Organ Systems > Organism - you
Cell Specialization
Cells uniquely suited to perform a particular function. Ex. blood cells, heart cells, brain cells
Connective Tissue
Connects and holds together structures in the body, providing structure and support - ex. ligaments which connect bones, and bones themselves. Also fills in spaces - ex. cartilage in your ears and nose.
Organism
Entire living thing that carries out all the basic life functions - ex. humans. Highest level of organization: cells>tissues>organs>organ systems>organism.
Tissues
Groups of similar cells that perform a specific function in an organism. Several types of tissues come together to form organs. The 4 types are - epithelial, connective, muscular, nervous.
Epithelial Tissue
Outer layer of tissue on the body - ex. skin. Also lines some of the body's inner surfaces - ex. lining of the stomach.
Muscular Tissue
Tissues that contract and expand, creating movement. ex. skeletal muscles move the body, the stomach has muscles that expand when full and relax when empty.
Nervous Tissue
Tissues that relay messages throughout your body. Ex. nervous tissue in the stomach sends messages to the brain when the body is hungry.
Organs
Two or more tissues that work together to perform a specific job. ex. heart, lungs, stomach, intestine,
