1. An introduction to the Nervous system From: http://www.hiogolffitness.com/?p=262http://www.hiogolffitness.com/?p=262

2. The importance of the nervous system Nervous systems reponse to stimuli (external or internal) by controling the actions of the body through electrochemical messages Allows us to: detect light, odour, temperature or pressure… just to name a few

3. What is the nervous system? Elaborate communication system (>100 billion nerve cells in the brain alone!) 2 main divisions (flow chart, p412): –central nervous system (CNS) Brain and spinal cord Coordinating system –peripheral nervous system (PNS) Nerves that carry info between organs and CNS Subdivided into somatic (skeletal muscle, bones and skin- relays info about environment) and autonomic (internal organs like the heart)

4. Anatomy of a nerve cell 2 types of cells –Glial: non-conducting cells important for structural support and metabolism –Neurons: functional units of the nervous system Can be sensory- sense and relay info from the environment to CNS for processing (photoreceptors for light, chemoreceptors for chemicals etc…) and are located in clusters called ganglia Or motor – relay information to the effectors (muscles, organs, glands) Or Interneurons – link neurons in the body (integrate sensory and motor neurons)

5. From: http://www.dmacc.edu/instructors/rbwollaston/Chapter_8_Nervous_System.h tm http://www.dmacc.edu/instructors/rbwollaston/Chapter_8_Nervous_System.h tm From: http://www.daviddarling.info/encyclopedia/N/neuron.htmlhttp://www.daviddarling.info/encyclopedia/N/neuron.html Sensory neuron Motor neuron

6. Parts of the neurons Dendrites: receive info from sensory receptors by conducting nerve impulses toward the cell body Axon: projects nerve impulses from the cell body Myelin sheath: covers many axons, insulates the neurons, preventing loss of charged ions from nerve cell. Formed by special glial cells called schwann cells. Nodes of Ranvier: areas between sections of myelin sheath, nerve impulses jump from one node to another (speeding up process)… so nerve impulses are quicker in mylelinated axons. Neurilemma: surrounds the axon and promotes re- generation of a damaged axon

7. Neural circuits Simplest nerve pathway is called a reflex arc Occurs without brain coordination 5 components: receptor, sensory neuron, interneuron, spinal cord, motor neuron and effector.

8. From: http://www.biologie.uni-hamburg.de/b-online/library/cat-removed/u3aos22.htmlhttp://www.biologie.uni-hamburg.de/b-online/library/cat-removed/u3aos22.html