The spinal cord begins at the occipital bone and extends down to the space between the first and second lumbar vertebrae; it does not extend the entire length of the vertebral column.
Earthworms are invertebrates, lacking a skeleton. To support and shape the body, they are filled with coelomic fluid. Earthworms sometimes appear to have a belt or saddle around their bodies; this is a clitelum, a structure containing maturing eggs.
Systems of the human body. Skin and nails are part of the integumentary system that helps protect the body. Earthworms have organ systems that help them move, breathe, and digest food. The endocrine system is responsible for producing and regulating hormones in the bloodstream to control bodily functions.The urinary system is a type of organ system that allows the body to rid itself of waste. The respiratory system is made up of the mouth, throat, nose, sinuses, bronchial tubes, and lungs.The torso houses many of the human body's organ systems.n biology, an organ system is a group of organs that work together for one purpose. Their interdependency on one another is critical for normal life functions, and if any one were to fail, it would subject the others to stress, possibly causing the whole group to shut down, with fatal results.