Chapter 3 Notes Biological psychologists study the relationship between the nervous system and behavior AKA neuroscientists Neurons nerve cells specialized for communication with each other our brain contains about 85 billion neurons components 1 The cell body AKA soma the central region of the neuron manufactures and provides continual renewal of new cell components contains the nucleus where proteins are manufactured 2 Dendrites branch like extensions that receive information from other neurons and pass them on to the cell body 3 Axons and axon terminals axons are transmitters specialized for sending messages to other neurons they are long tail like extensions near the cell body a Synaptic vesicles spherical sac containing neurotransmitters travel the length of the axon to the axon terminal b Neurotransmitters chemical messengers that neurons use to communicate with each other released when the synaptic vesicle reaches the axon terminal 4 Synapses tiny fluid filled spaces between neurons through which neurotransmitters travel a Synaptic cleft a gap in the synapse into which neurotransmitters are released from the axon terminal Glial cells cells in the nervous system that play a role in the formation of the myelin and the blood brain barrier respond to injury remove debris and enhance learning and memory types 1 Astrocyte the most abundant glial cell communicates closely with neurons increases the reliability of their transmission control blood flow in the brain and play a vital role in the development of the embryo involved in thought memory and the immune system found in abundance in the blood brain barrier 2 Oligodendrocyte promotes new connections among nerve cells and releases chemicals to aid in healing produces the myelin sheath Blood brain barrier a protective shield that insulates the brain from infection by bacteria and other intruders blood vessels are wrapped with a fatty coating blocking large molecules highly charged particles and molecules that dissolve in water but not fat from entering the brain Myelin sheath insulating wrapper around axons contains numerous gaps along the axon called nodes which help the neuron conduct electricity more efficiently nodes speed up transmission Electrodes small devices made from wire or fine glass tubes that record electrical activity allows researchers to measure the potential difference in electrical charge inside and outside the neuron Resting potential when there are no neurotransmitters acting on the neuron there are more negative particles inside the neuron than outside in this state Threshold when the electrical charge inside the neuron reaches a high enough level relative to the outside once this threshold is reached an action potential is triggered Action potential electrical impulse that travels down the axon triggering the release of neurotransmitters steps 1 Abrupt waves of electrical discharge triggered by a change in charge inside the axon 2 Neuron is firing 3 Action potentials originate in the trigger zone near the cell body and continue down the axon to the axon terminal 4 Positively charged particles flow rapidly into the axon and rapidly out causing a spike in positive 5 charge followed by a sudden decrease in charge Inside charge ends up at slightly more negative than original resting value producing a charge in electricity 6 Charge reaches axon terminal triggers release of neurotransmitters into the synapse Absolute refractory period brief interval following each action potential during which another action potential cannot occur limiting factor for the rate at which action potentials can travel Receptor sites location along the dendrites that uniquely recognizes a neurotransmitter after a neurotransmitter is released into the synapse it binds with these receptor sites different receptor sites recognize different types of neurotransmitters Reuptake means of recycling neurotransmitters back into the axon terminal a continually occurring process in which the synaptic vesicle reabsorbs the neurotransmitter Types of neurotransmitters 1 Glutamate main excitatory neurotransmitter in the nervous system participates in relay of sensory information enhances learning and memory of the 2 most common neurotransmitters in the CNS interacts with alcohol and memory enhancers 2 Gamma aminobutyric acid GABA main inhibitory neurotransmitter in the nervous system of the 2 most common neurotransmitters in the CNS interacts with alcohol and anti anxiety drugs 3 Acetylcholine ACh muscle contraction and corticol arousal selective attention and sleep 4 Monoamines contain only 1 amino acid a Norepinephrine NE brain arousal mood hunger sleep b Dopamine motor functions and reward experiences after accomplishing goals c Serotonin mood temperature regulation aggression and sleep cycles 5 Anandamide pain reduction increase in appetite memory and sleep 6 Neuropeptides short strings of amino acids a Endorphins pain reduction Psychoactive drugs drugs that interact with neurotransmitter systems affecting mood arousal and behavior 1 Agonists increase receptor site activity by allowing neurotransmitters to remain in the synapse 2 Antagonists decrease receptor site activity by blocking neurotransmitters from binding to longer than usual receptors Plasticity term used by scientists to describe the nervous system s ability to change our brains are most flexible during early development 4 primary ways the network of neurons changes in our brains over the course of development 1 Growth of dendrites and axons 2 Synaptogenesis the formation of new synapses 3 Pruning death of certain neurons and the retraction of axons to remove connections that are not useful 4 Myelination insulation of axons with the myelin sheath Neurogenesis the creation of new neurons in the adult brain Stem cells a cell often originating in embryos that has the capacity to differentiate into a more specialized cell Central nervous system CNS part of the nervous system containing the brain and spinal cord that controls the mind and behavior 6 distinct systems 1 Cortex a Frontal lobe performs executing functions that coordinate other brain areas motor planning language and memory b Parietal lobe processes touch information integrates vision and touch c Temporal lobe processes auditory information language and autobiographical memory d Occipital lobe processes visual information 2 Basal ganglia controls movement and motor planning 3 Limbic system a Thalamus conveys sensory