The brain is the central organ of the nervous system, responsible for controlling and coordinating all bodily functions. It is protected by the skull and is divided into several regions, including the cerebrum, cerebellum, and brainstem.

The spine, also known as the spinal column or vertebral column, is a series of interconnected bones called vertebrae that run from the base of the skull to the tailbone. The spine houses and protects the spinal cord, which is a long, thin bundle of nerves that extends from the brainstem to the lower back.

The spinal cord is responsible for transmitting sensory and motor signals between the brain and the rest of the body. It is divided into several segments, each of which gives rise to a pair of spinal nerves that exit the vertebral column and branch out to various parts of the body.

The pathways of large and small circulation refer to the flow of blood through the heart and blood vessels. Large circulation refers to the flow of oxygenated blood from the heart to the body's tissues and the return of deoxygenated blood to the heart. Small circulation refers to the flow of deoxygenated blood from the heart to the lungs, where it is oxygenated, and the return of oxygenated blood to the heart.

The model adopts a relief style, visually demonstrating the brain and spineThe distribution of spinal cord and spinal nerves, as well as the pathways of large and small circulation