1. The Nervous System  Nervous System  the body’s speedy, electrochemical communication system  consists of all the nerve cells of the peripheral and central nervous systems  Central Nervous System (CNS)  the brain and spinal cord  Peripheral Nervous System (PNS)  the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

2. © 2004 John Wiley & Sons, Inc. Huffman: PSYCHOLOGY IN ACTION, 7E The Nervous System (Controls self-regulated action of internal organs & glands) (Controls voluntary movements of skeletal muscles) Arousing – fight or flight Calming – rest or digest

3. The Autonomic Nervous System

4. The Nervous System

6. The Spinal Cord

7. The Nervous System  Reflex  a simple, automatic, inborn response to a sensory stimulus Skin receptors Muscle Sensory neuron (incoming information) Motor neuron (outgoing information) Brain Interneuron Spinal cord

8. Cells of the Nervous System: Neurons and Glia Neurons: Specialized cells that rapidly respond to signals and quickly send signals of their own Glial cells (Neuroglia): Cells that help hold neurons together and help neurons communicate with one another

9. Glial Cells (Neuroglia) Support network of cells surrounding the neurons & blood vessels of the brain & nervous system – Outnumber neurons 10-1 Types: – Oligodendroglia –produce myelin in CNS – Schwann cells – produce myelin in PNS; can help axons regenerate – Astrocytes – star-shaped; form matrix in which neural cells are embedded; envelope blood vessels in brain; absorb dead neural cells

10. Neurons and Synapses Types of Neurons Sensory (Afferent) Motor (Efferent) Interneurons Millions Billions

11. Spinal Cord Brain Sensory Neuron Sensory (Afferent) Neurons INPUT Carry messages from body’s tissues & sensory organs to the brain & spinal cord. AFFERENT = toward the brain Drawing shows a somatosensory neuron Vision, hearing, taste and smell nerves are cranial, not spinal

12. Spinal Cord Brain Sensory Neuron Motor Neuron Motor (Efferent) Neurons OUTPUT Carry messages from the brain and spinal cord To the muscles and glands. EFFERENT = away from the brain

13. Spinal Cord Brain Sensory Neuron Motor Neuron Interneurons Interneurons carry information between sensory & motor neurons. Only found in the brain and spinal cord.

14. Neural Structure http://www.youtube.com/watch?v=FR4S1Bqd FG4&feature=related (Neurons and How They Work) http://www.youtube.com/watch?v=FR4S1Bqd FG4&feature=related

15. Structures of a neuron

16. Dendrites Receive info/inputs from neighboring neurons May receive thousands of inputs Send to cell body

17. Dendritic Growth Mature neurons generally can’t divide But new dendrites can grow Provides room for more connections to other neurons New connections are basis for learning

18. The cell body – Round, centrally located structure – Contains DNA; life support center zContains the cell’s Nucleus

19. Axon Output structure; sends messages One axon per cell, Lengths vary up to several feet long

20. Myelin sheath White fatty tissue on axon of some neurons; set by age 25 Acts as an electrical insulator Increases the speed of neural signals down the axon. Spaces between myelin = nodes of Ranvier Myelin Sheath