Organization of Living Things

Living things are organized… Cells are organized into tissues, Tissues are organized into organs Organs work together to form organ systems Organ systems are vital to a healthy organism

What is an organism? An organism is a body made up of organs, organelles, or a combination of both, that work together to carry on the various processes of life

Cells Cells make up the structure of an organism Some organisms are unicellular. They are made of only one cell. Other organisms are multi-cellular. They are made of many cells. Multi-cellular organisms contain many types of cells; each cell performs a specific task to maintain the life of the organism.

Tissues Tissues are groups of similar cells acting together to perform specific functions in the body of an organism

Epithelial Tissue The cells of this tissue pack tightly together to form sheets of tissue These “sheets” serve as membranes lining organs to keep the body’s organs separate, in place, and protected Examples include the outer layer of the skin, the inside of the mouth and stomach, and tissue surrounding the body’s organs

Connective Tissue This tissue adds support and structure to the body Most connective tissue contain a long, stringy protein called collagen that makes this tissue strong Some examples include the inner layers of skin, tendons, ligaments, cartilage, bone and fat tissue Blood is also considered a connective tissue

Muscle Tissue This is a special tissue that can contract (bunch up) Muscle tissue contains two special proteins called actin and myosin that slide past one another and allow movement Examples of muscle tissue are contained in the muscles throughout your body

Nerve Tissue Nerve tissue has the ability to generate and conduct electrical signals in the body These electrical messages are managed by nerve tissue in the brain and transmitted down the spinal cord to the body.

Organs Organs are specialized parts of an organism that perform a specific function Organs contain at least two different types of tissue working together for a common purpose Examples include the heart, brain, kidneys, liver, and even the skin (which is the body’s largest organ!)

Organ Systems Organ systems are groups of organs that work together to accomplish a specific task within the organism There are 10 major organ systems in the human body:

Skeletal System Provides support for the body Protects delicate internal organs Provides attachment sites for the organs Major Parts: Bones Cartilage Tendons Ligaments

Skeletal System

Muscular System The main role is to provide movement This includes the movement of limbs for mobility and The movement of materials through organs, such as the stomach and intestine Major Parts: Skeletal Muscles Smooth muscles (found throughout the body)

Muscular System

Integumentary System Guard the body’s physical and biochemical integrity Maintain a constant body temperature Provide sensory information about the surrounding environment. 4. Largest organ system

Reflection Question Name the body systems that work together. Why do you think it is important that these organ systems work together?