Contains the full lesson along with a supporting toolkit, including teachers’ notes.
Our bodies have over ten million million (1013) living cells which must work in co-operation for us to live and grow. To co-operate they must communicate. The brain, spinal cord, nerves, sense organs and receptors are the vital parts of the human nervous system that facilitate communication between our cells. In this lesson we will look at the formation and function of the nervous system.
How is our nervous system formed?
The central nervous system (CNS) begins to form halfway into the embryonic period, 28 days after conception. The development of the central nervous system is the first major event in the formation of organs in the developing embryo.
The nervous system develops from the ectoderm , the outer of the three germ layers. The skeletal system develops from themesoderm , the middle of the germ layers, with the cranium and vertebrae forming a protective cover around the brain and spinal cord.
How are messages transferred?
The brain is the main command centre sending and receiving signals to and from all parts of the body, storing information and giving us the amazing ability of self-awareness, i.e. consciousness.
The spinal cord is a complex dual carriageway. Information passes rapidly between the brain and almost all the organs of the body.
Signals are conducted along specialised cells called neurons. There are three types of neuron; sensory neurons , motor neurons and interneurons. The neurons do not connect directly with one another; there is a small gap between them, called the synaptic cleft .