I will understand the roles of neurons in sensing and responding I will understand the roles of neurons in sensing and responding. MT: Organ Systems Photo Credit: AP/Wide World Photos. Copyright Pearson Prentice Hall

To sense and respond! The Nervous System What are the functions of the nervous system? To sense and respond! Copyright Pearson Prentice Hall

The messages carried by the nervous system are sent by neurons. Copyright Pearson Prentice Hall

Parts of a Neuron Nucleus Dendrites Axon terminals Cell body Myelin sheath The nervous system controls and coordinates functions throughout the body. The basic units of the nervous system are neurons. Axon Copyright Pearson Prentice Hall

Cell Body The largest part of a neuron is the cell body. It contains the nucleus and much of the cytoplasm. Cell body Copyright Pearson Prentice Hall

Dendrites Dendrites gather signals surrounding the neuron. Dendrites Copyright Pearson Prentice Hall

Neurons The axon is the long tube that carries signals away from the cell body. Axon terminals Axon Copyright Pearson Prentice Hall

The axon ends in axon terminals. Chemicals are released to next neuron. Axon terminals Copyright Pearson Prentice Hall

Myelin sheath The axon is surrounded by lipids (fat) called the myelin sheath which helps the signal travel fast. Myelin sheath Copyright Pearson Prentice Hall

synapse Space where chemicals travel from one neuron to the next. Copyright Pearson Prentice Hall

A = sensory neuron C = interneuron B = motor neuron Types of Neurons For feeling Body to spinal cord or brain Inter As a bridge In brain and spinal cord Motor For movement Brain or spinal cord to body A = sensory neuron C = interneuron B = motor neuron

Neurons Sensory neurons: carry impulses from the sense organs (body) to the spinal cord and brain. Motor neurons carry impulses from the brain and spinal cord to muscles and glands (body). Interneurons connect sensory and motor neurons and carry impulses between them. Copyright Pearson Prentice Hall