Neurons The Building Blocks of the Nervous System

Neurons: The Building Blocks of the Nervous System

Biological Psychology n n Branch of psychology concerned with the links between biology and behavior Biological psychologists call themselves ¡ ¡ ¡ behavioral neuroscientists neuropsychologists behavior geneticists physiological psychologists biopsychologists

Nervous System n n n The electrochemical communication system of the body Brings information to the brain from the senses Sends messages from the brain to the body for movement

Neuron n n The basic building block of the nervous system—a nerve cell Neurons perform three basic tasks ¡ Receive information ¡ Carry the information ¡ Pass the information on to the next neuron

Think Pair Share n Share one thing you learned and one question you have about the parts and functions of the neuron

Parts of the Neuron (#1)

Parts of the Neuron - Dendrites

Parts of the Neuron - Soma

Parts of the Neuron - Axon

Parts of the Neuron – Myelin Sheath

Parts of the Neuron - Terminals

Neural Communication: The Neural Impulse

Neurons n n Neurons “fire”— send an impulse down their length— or they don’t “fire” Neurons come in a variety of shapes, sizes, etc.

Think Pair Share n Share one thing you learned and one question you have about the neural impulse.

Neural Communication (#2) n Action Potential ¡ ¡ ¡ A neural impulse A brief electrical charge that travels down the axon of the neuron. Considered an “on” condition of the neuron

Refractory Period n n The “recharging phase” when a neuron, after firing, cannot generate another action potential Once the refractory period is complete the neuron can fire again

Resting Potential n n The state of a neuron when it is at rest and capable of generating an action potential The neuron is set and ready to fire

All-or-None Principle n n The all-or-none law is the principle that the strength by which a neuron responds to a stimulus is independent of the strength of the stimulus. As long as there is enough energy to trigger the cell, it will give a complete response; otherwise, there is no response.

Communication Between Neurons

Think Pair Share n Share one thing you learned and one question you have about how neurons communicate.

Synapse n n n The tiny, fluid filled gap between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron Tiny gap at this junction is called the synaptic gap or cleft The action potential cannot jump the gap

Neurotransmitters n n n Chemical messengers that traverse the synaptic gap between neurons Released by sending neuron, bind to receptor sites on the receiving neuron Influence whether the second neuron will generate an action potential or not

Excitatory Effect n n A neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential (impulse) The second neuron is more likely to fire

Inhibitory Effect n n A neurotransmitter effect that makes it less likely that the receiving neuron will generate an action potential (impulse) The second neuron is less likely to fire

Build Your own Neuron

5 Minute Pause… n Both write down and share 1 question you have about ¡ ¡ ¡ n Neurons The Neural Impulse OR Communication between Neurons Partner tries to clarify or re-teach

Neural Communication: The Neural Chain

Receptor Cells n n Specialized cells in the sensory systems of the body that can turn other kinds of energy into action potentials that the nervous system can process Receptor cells in the eye turn light into a neural impulse the brain understands.

Sensory Nerves n n Nerves that carry information to the central nervous system Connect the sense organs to the brain and spinal cord

Interneurons n Nerve cells in the brain and spinal cord responsible for processing information related to sensory input and motor output

Motor Nerves n Nerves that carry information from the central nervous system