3 Levels of Organization The levels of organization in a multicellular organism—atoms, cells, tissues, organs, and organ systems.OrganismOrgan SystemOrgansTissuesCellsAtoms
4 Cell Types and TissueA cell --the basic unit of structure and function in living things. Specialized cells are uniquely suited to perform a specific function.Tissues are groups of cells that perform a specific function.Muscle Tissue: works with bones to enable body to move.Epithelial Tissue: glands and tissues that cover interior and exterior body surfaces.Connective Tissue: provides support for the body and connects its parts.Nervous Tissue: transmits nerve impulses throughout the body.
5 Human Body SystemsEach organ in your body is part of an organ system, a group of organs that work together to perform a major function.
6 Circulatory SystemYour heart is part of your circulatory system, which carries oxygen and other materials throughout your body. Besides the heart, blood vessels are organs that work in your circulatory system.
7 Nervous SystemThe nervous system detects and interprets information from the environment outside the body and from within the body; controls most body functions. Structures include brain, spinal cord, and nerves.
8 Lymphatic SystemThe lymphatic system fights disease and collects fluid lost from blood vessels and returns the fluid to the circulatory system. Includes white blood cells, thymus, spleen, lymph nodes, and lymph vessels.
9 Excretory SystemThe excretory system removes wastes. The organs involved are the kidney, ureter, urinary bladder, and urethra.
10 Muscular SystemThe muscular system works with the skeletal system to enable the body to produce voluntary movement, moves food through the digestive system, and helps to circulate blood by keeping the heart beating. Includes muscles and tendons.
11 Skeletal SystemThe skeletal system supports the body, protects internal organs, allows movement; makes and stores blood cells and mineral reserves. Includes bones, cartilage, and ligaments.
12 Digestive SystemThe digestive system takes food into the body, breaks the food down into smaller particles, absorbs the digested materials, and eliminates wastes. Includes mouth, pharynx, esophagus, stomach, intestines, and rectum.
13 Respiratory SystemThe respiratory system takes oxygen into the body and eliminates carbon dioxide. Includes nose, pharynx, larynx, trachea, bronchi, bronchioles, aveoli, and lungs.
14 Endocrine SystemThe endocrine system controls many body processes using hormones.It is responsible for growth, development, and metabolism.This system also maintains homeostasis.Includes pituitary, pineal, thyroid, thymus, adrenal, ovary and testes and pancreas.
15 Integumentary SystemThe integumentary system serves as a barrier against infection and injury. Also, it helps to regulate body temperature. Includes skin, hair, nails, sweat and oil glands.
16 Reproductive SystemThe reproductive system produces sex cells that can unite with other sex cells to create offspring; controls male and female characteristics. Includes (in males) testes, vas deferens, urethra, penis and (in females) uterus, ovaries, fallopian tubes, and vagina.