The I began an introduction to the nervous system, the biological foundation for the study of the science of psychology.

•   Body/brain/mind connection. The mind is a function of all three, but the brain is the 'control central", the master computer, the CEO that determines 'mind'. The brain is an organ, a group of specialized cells with biological functions, but so is the heart (and the Greeks thought that the heart was the locus of mind), the liver. the kidneys, etc. Your individual mind is made up of your unique thoughts, emotions, creativity, personal history and factual memories, self-awareness, problem solving style and ability, etc. The body is the sensor and conveyer of information about the world outside the brain, it's support system, and its servant, carrying out it's orders.

b. Evolutionary perspective on the nervous system.

The nervous system is the primary communications system of the body. (Other communication systems include the endocrine system and the immune system.)

One-celled animals do not need elaborate systems of communication to accomplish the tasks necessary for their survival. The more complex the communication and coordination needed between the parts of a multi-celled organism, the more elaborate and specialized the nervous system becomes. One-celled animals such as the amoeba and paramecium do not need nervous systems. We discussed the simple, diffuse nerve cells of the hydra, which lives it's life attached to a rock and moves its tentacles by simple reflex actions, to the jelly fish, which is mobile and needs to coordinate its contractions, to the earthworm, in which each segment contracts much like a jelly fish, but in coordinated sequences to move through the earth in search of food, mates, etc.  The spinal cord evolved out of this primitive precursor of the organization of nerves. As the nervous system became more centralized and more critical to subsistence and survival, the main parts of this critical and vulnerable system became encased in protective bones of  the spinal column and the skull.

 The brain and spinal cord,  encased in bone, have no direct contact with the outside world. The spinal cord coordinates simple reflex actions much like the contraction of the hydra's tentacles, but the brain is the CEO (Chief Executive Officer, in the business world model of organization), the CPU (Central Processing Unit, in computerese) and relies on the sensory systems to bring in information, which it organizes or processes into meaningful patterns and then directs the rest of the body in its response to that outside world. These two critical components of the nervous system or referred to as the  Central Nervous System (CNS), while the nerves that bring information in from the senses and deliver messages and directions to the body are referred to as the Peripheral Nervous System (PNS).

We will look at how these and pother aspects of the nervous system work in the coming weeks.