FIVE LEVELS OF ORGANIZATION SUMMARIZE THE LEVELS OF STRUCTURAL ORGANIZATION WITHIN THE HUMAN BODY. Cellular Organization

Levels of Organization From smallest to largest: Cells Tissues Organs Organ systems Organism

Cells Cell – basic unit of structure and function in living things. Cells make up all living things.

The Benefits of Being Multicellular Larger size  The larger you are, the less predators you have, and you can eat larger prey! Longer life  Longer life-span than unicellular organisms. Specialization  Each type of cell has a particular job.  This makes the organism more efficient.

Tissues Tissue – group of similar cells that perform the same function. Most animals (including humans) have four basic types of tissue:  Muscle tissue  Nerve tissue  Connective tissue  Protective tissue

Muscle Tissue Muscle tissue – makes parts of your body move by contracting (shortening) and relaxing. In some cases, like throwing a ball, you control the movement. In other cases, such as the beating of your heart, the movement occurs without conscious control.

Nerve Tissue Nerve tissue – carries messages back and forth between the brain and every other part of the body.

Connective Tissue Connective Tissue – provides support for your body and connects all its parts.  Ex:  Bone – supports & protects  Fat – insulation & energy storage  Blood  Tendons  Ligaments  cartilage

Epithelial Tissue Functions as a boundry. Covers the surfaces of the body, inside (as lining/or covering of internal organs) and outside of the body.

Organs Organ – structure composed of two or more different types of tissue that work together for a specific function.  Each organ performs a specific job.  Ex:  Heart – pumps blood throughout the body  Stomach – breaks down food so that it can be absorbed by the intestines.

Organ Systems Organ system – a group of two ore more organs that work together to perform a specific job. Ex:  Circulatory system – heart, blood vessels, blood There are 11 different organ systems in the human body. Circulatory, digestive, endocrine, excretory, immune, integumentary (skin), muscular, nervous, reproductive, respiratory, and skeletal.

Organism Organism - a living thing

Structure & Function Structure - the arrangement of parts in an organism  Includes the shape of a part and the material from which it is made. Function - the job the part does  Ex: structure of lungs (spongy sac) is related to its function

Homeostasis The different organ systems work together and depend on one another.  Ex:  Respiratory, digestive & circulatory systems work together to fuel muscles with the energy they need. The systems of the human body work together to maintain homeostasis. Your body is constantly regulating internal conditions.  Blood sugar, posture, temperature.