3.1.2 Biopsychology Psychology Physiological Psychology Be able to state the meaning of the new key words for this approach Be able to describe the structure and function of a motor neuron, a sensory neuron and an interconnecting neuron. Be able explain how electrical messages are transmitted from one neuron to another. Objectives 5 minutes

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Write one sentence about what the following features do Dendrite Receives the nerve impulse or signal from adjacent neurons Axon where the electrical signals pass along. Myelin sheath Insulates /protects the axon from external influences that might effect the transmission of the never impulse down the axon. Synaptic terminals Terminal buttons send signals to an adjacent cell.

Neurotransmissions Dopamine http://www.youtube.com/watch?v=lCK2uauYkxE 1.21 – 3.55 The Neuron & Neural Transmission (1 of 3) 7.50 - end Start – 1.17 Click here to see how the Neurons work. Part 2

Communication within neurons is electrical Communication within neurons happens through the process of conduction An electrical signal is sent down the length of the axon. This electrical signal is called an “action potential” Some axons are myelinated (i.e., covered with a fatty tissue called the myelin sheath)—myelinated axons allow for quicker transmission of the electrical impulse.

Communication between neurons is chemical When the electrical impulse reaches the terminal buttons, they release chemicals called neurotransmitters into the synapse. These neurotransmitters connect with receptor sites (located mostly on the dendrites, but also some on the soma) of nearby neurons. The neurotransmitters “fit in” to these receptor sites like locks into keys

Synapse between two neurons.

Label this Synapse What you need to label: Direction of impulse. Axon Synaptic vesicles containing neurotransmitter Synaptic cleft terminal button Dendrite Receptor site

Communication between neurons is chemical In this “lock & key” fashion, neurotransmitters unlock tiny channels at the receiving sites on nearby neurons, and electrically charged atoms enter the receiving neuron. These electrically charged atoms—through altering the electrical charge of the receiving neuron—either excite or inhibit its readiness to fire an electrical impulse down it’s axon

Communication within neurons is electrical Neurons fire when their electrical charge reaches what is called the threshold of excitation. When this threshold is reached, they send an electrical charge or impulse down their axons. This electrical impulse is called “an action potential.”

Communication between neurons is chemical and within neurons is electrical… Through binding with receptor cells, neurotransmitters alter the likelihood of the receiving neurons reaching the threshold of excitation, thus they are either inhibitory (make the firing of the receiving neuron LESS likely) or excitatory (make the firing of the receiving neuron MORE likely).

Neurotransmitters… …are chemicals that are released into the synapse by neurons. These neurotransmitters are “taken back up” into the terminal buttons of neurons through the process of reuptake

Label this Synapse What do the following do: Synaptic vesicles containing neurotransmitter Synaptic cleft terminal button Dendrite Receptor site

questions What are Endorphins? A collection of neurotransmitters that affect mood. Name a drug that contains serotonin. LSD Which chemical affects voluntary movement? Dopamine These neurons receive messages from the outside world. Sensory neurons What do Motor Neurons do? Carry nerve impulses from the CNS to the muscles These neurons are located mostly in the brain. Interneurons