1. Nervous System

2. Functions of the Nervous System Monitor internal and external environments Integrate sensory information Coordinate voluntary and involuntary responses

3. Divisions of the Nervous System Central Nervous System Brain and spinal cord Peripheral Nervous System Somatic nervous system Autonomic nervous system Sympathetic nervous system Parasympathetic nervous system

5. Cellular Structures Neurons Dendrites Axon Myelin Sheath Synaptic terminals Neuroglia Regulate the environment around neurons Are phagocytes that help degrade waste material and foreign material

6. Types of Neurons Multipolar Neurons Two or more dendrites and a single axon Most common type of neuron in the CNS All motor neurons Unipolar Neurons Dendrites and axon are continuous Cell body lies off of one side of the axon Most sensory neurons in the PNS Bipolar Neurons Two axons and two sets of dendrites with a cell body in between them Very rare, typically found in specialized sense organs (eyes, ears, nose)

10. Sensory Neurons Roughly 10 million neurons in afferent division Receive information from internal and external environment, information is relayed to brain for interpretation Somatic Sensory Receptor External Receptors: information from external environment (touch, sight, taste, etc) Proprioceptors: position of limbs Visceral Receptors (internal receptors) Monitor activities of internal organs (stretch receptors in the bladder)

11. Motor Neurons Roughly 500,000 neurons in efferent division Act on an effector organ Divided into somatic motor neurons and visceral motor neurons

12. Interneurons Roughly 20 billion Link neurons together Allow for movement of messages between neurons

13. Neuroglia (CNS) Astrocytes Create the blood brain barrier BBB is caused by chemical secretions of astrocytes that make capillaries impermeable to most chemical compounds Parkinson’s Disease Oligodendrocytes Responsible for myelination in the CNS Creates “white matter” in the brain Increases the speed of action potentials through the axon Node of Ranvier

14. Neuroglia (CNS) Microglia Phagocytes Degrade waste material and foreign material Important for overall brain health Ependymal Line the ventricles and central canal of the spinal cord Responsible for making cerebrospinal fluid Responsible for circulating CSF

15. Neuroglia (PNS) Satellite cells Similar function to astrocytes Surround and support neurons Schwann cells Responsible for myelination in the PNS

17. Activity Draw a multipolar neuron Label the following structures: cell body, axon, myelin sheath, Node of Ranvier, dendrites, synaptic terminal In a paragraph, explain the role of glial cells (give specific examples)