Nervous system I Chapter 10 Nervous system Trillions

Nervous system I Chapter 10

Nervous system • Trillions of nerve cells linked together in a highly organized manner to form the rapid control system of the body • Neurons- nerve cells, carry electrical signals rapidly and over long distances

Divisions of the nervous system • Central nervous system (CNS) – Brain – Spinal cord • Peripheral nervous system (PNS) – Nerves in other parts of the body – Spinal and cranial nerves

Brain Cranial nerves Spinal cord Spinal nerves

General functions of the nervous system • Sensory – Gather information – Info carried to CNS • Integrative – Sensory information used to create sensations, memory, thoughts, decisions • Motor – Decisions acted upon – Information carried from CNS to PNS

Two broad types of nerve paths

Cells of the nervous system • Neuron • Glia

Neurons • Vary in size and shape • Share certain features – Dendrites- receive signal – Cell body- contains nucleus – Axon- transmits signal to another neuron

Neuron structure • Dendrites – Receive incoming signals – Transfer to cell body of neuron • Cell body – Typical cell structures – cytoskeleton

Neuron structure • Axon – Transmits signal to synapse

Neuron structure- synapse • Region where axon meets target cell • Space across which neurotransmitter diffuses

Myelination of axons • Myelin- lipids and proteins that wrap around an axon • White matter – Contains myelinated neurons • Gray matter – Contains unmyelinated neurons Dendrite Unmyelinated region of axon Myelinated region of axon Node of Ranvier Axon Neuron cell body Neuron nucleus

• http: //www. youtube. com/watch? v=x 4 PPZCLn Vk. A&list=PL 3 EED 4 C 1 D 684 D 3 ADF&index=26