Neurons and Neurotransmitters

The brain https://www.youtube.com/watch?v=vHrmiy4W9C0

Neurons Neurons are the basic unit of the nervous system They use electro-chemical means to conduct electrical impulses There are about 100 billion neurons in the CNS

Three main types of neurons Sensory neurons Transmit information from the sensory receptors to the CNS Interneurons Connect sensory neurons to motor neurons in the spinal cord Motor neurons Send information from the CNS to muscles and glands

Withdrawal Reflex Figure 2.5B from: Kassin, S. (2001). Psychology, third edition. Upper Saddle River, NJ: Prentice Hall.

How neurons work Neurons: receive conduct & transmit electrical impulses using electro-chemical processes Electro-chemistry is the production of electricity through chemical reactions In simple terms: Electricity is the movement of electrons Electro-chemistry is the movement of ions

Dendrites of another neuron Neurons: anatomy Cell body Dendrites Axon Myelin sheath Dendrites of another neuron Axon of another neuron

Action Potential The electro-chemical transmission of an electrical impulse through the neuron is called an action potential The dendrites receive the impulse from the axon of the previous neuron The action potential is then conducted to the cell body and down the axon It is then transmitted to the dendrites of the next neuron

NEURONS 3. 1. 2. Figure 2.6 from: Kassin, S. (2001). Psychology, third edition. Upper Saddle River, NJ: Prentice Hall. Source: Neurons = 3 functions: reception, conduction, transmission

The synapse The axon of one neuron connects to the dendrites of the next neuron There is a space in between the axon of the first neuron and the dendrites of the next one This space is called the synapse A nerve impulse travels from the dendrites, through the cell body, the axon, across the synapse and into the dendrites of the next neuron

neurotransmitters Neurotransmitters are chemical messengers that carry the action potential across the synapse There are different types of neurotransmitters, but each works in the same way

Myelin Sheath FUNCTION Insulates the axon Allows for rapid movement of the action potential along the axon