2. THE NERVOUS SYSTEM

3. Definition: A network of billions of nerve cells linked together to form the rapid control center of the body. Main function: Integrating center for homeostasis, movement, and almost all other body functions.

4. The nervous system is made of: The brain The spinal cord The nervesThe senses

5. BASIC FUNCTIONS OF THE NERVOUS SYSTEM 1.Sensation Monitors changes/events occurring in and outside the body. Such changes are known as stimuli and the cells that monitor them are receptors. 2.Integration Parallel processing and interpretation of sensory information to determine the appropriate response 3. Reaction Activation of muscles or glands (typically via the release of neurotransmitters (NTs))

6. ORGANIZATION OF THE NERVOUS SYSTEM 1.Central Nervous System The brain + the spinal cord The center of integration and control 2.Peripheral Nervous System Spinal nerves + Cranial nerves The nervous system outside of the brain and spinal cord

7. PERIPHERAL NERVOUS SYSTEM Responsible for communication between the CNS and the rest of the body. Can be divided into: Sensory Division: Conducts impulses from receptors to the CNS Motor Division: Conducts impulses from CNS to effectors (muscles/glands) Can be divided further: Somatic nervous system Autonomic nervous system

8. MOTOR DIVISION Somatic nervous system VOLUNTARY (generally): Conducts impulses from the CNS to skeletal muscles Autonomic nervous system INVOLUNTARY (generally): Conducts impulses from the CNS to smooth muscle, cardiac muscle, and glands.

10. NERVOUS TISSUE 2 cell types 1.Neurons Functional, signal conducting cells 2.Neuroglia Supporting cells 1. 2.

11. BASIC NERVE CELL STRUCTURE

13. 3 MAIN TYPES OF NERVE CELLS sensory neuron relay neuron motor neuron

14. SENSORY NEURONS Carries impulses from receptors e.g pain receptors in skin to the CNS (brain or spinal cord)

15. RELAY NEURON Carries impulses from sensory nerves to motor nerves.

16. MOTOR NEURON Carries impulses from CNS to effector e.g. muscle to bring about movement or gland to bring about secretion of hormone e.g LH

17. http://tle.westone.wa.gov.au/content/file/969144ed-0d3b-fa04-2e88-8b23de2a630c/1/human_bio_science_3b.zip/content/002_nervous_control/page_03.htm The axon is only 10µm in diameter but can be up to 4m in length in a large animal!} And in humans up to 1m large! http://www.tokresource.org/tok_classes/biobiobio/biome nu/metathink/required_drawings/index.htm