A.P. Psych Review
There are two communication systems in the brain
The Nervous System and the Endocrine System
Nervous System: extensive network of nerve cells that carry messages in pulses of electrical and chemical energy throughout the body. This is the network that first comes to your rescue by accelerating you heart and tensing your muscles for action. Endocrine System: a slower acting communication network that sends a follow up message that supports and sustains that support the emergency response initiated by the nervous system. They send these messages through chemical messengers known as hormones. The cooperation between the endocrine and nervous system is at the hypothalamus. The Neuron: The Building Block of the Nervous System
The nervous system is made up of nerve cells called neurons. Neuron: a nerve cell that receives processes and transmits information to other cells. The speeds in which they do so are within fractions of seconds. There are three different types of neurons, varying in size and shapes but have similar structure. Sensory Neurons (Afferent) - they carry information from the sense organs towards the brain. They essentially act like one-way streets. Ex: when you test water temperature in your shower with your hand, sensory neurons carry the message towards the brain. Motor Neurons (Efferent) – also one-way streets but they carry information away from the brain to muscles, organs and glands. Ex: in the shower, the motor neurons deliver the message from the brain that tells your hand how much to move the shower control knob. Interneurons: because motor and sensory neurons do not interact, the interneurons are the neurons that relay messages between motor, sensory and other interneurons.
How Neurons Work
Dendrites: receive incoming messages. They are branched fibers acting like a net to collect messages received by direct stimulation Soma: the dendrites pass on these messages to the soma which is the cell body. It contains the nucleus and life-support machinery. It assessing the messages that they receive from the dendrites. Exhibitory- excite neurons and tell them to fire. It causes an action potential. Inhibitory- tells the neuron to not fire and prevents an action potential. Axon- when excitatory triumphs over inhibitory; the neuron sends a message through the transmitter fiber known as the axon. Axon gets electric energy from ions.
Resting Potential-the inside of a neuron has a negative charge of 70. Action Potential- When the cell body becomes excited it triggers the action potential. Negative to positive charge. There is a rapid influx of positive ions. An electrical signal is sent along the axon. All or none principle- the axon either fires or it doesn’t Synapse- gap between nerve cells.
Terminal Buttons- the neuron must pass here to reach the synapse Synaptic Transmission- electrical message morphs into a chemical message so it can cross the synapse. Synaptic vessels- contain neurotransmitters
The vesicles spill their transmitters into the synaptic cleft. Lock and key principle. Reuptake- transmitters that relay messages which are recycled to the terminal buttons and the presynaptic neuron. Presynaptic- where it came from
Postsynaptic- where it goes.
Acetylcholine-excitatory. Casues contraction of muscles, regulates heart muscles and it involve in memory Dopamine- excitatory- involved in motivation and reward, alertness and linked to schizophrenia. Serotonin- inhibitory and excitatory. Associated with mood, sexual activity and emotions Endorphins- inhibitory- pleasurable sensations and control of pain Norepinephrine- excitatory or inhibitory- neurons in autonomic nervous system and most neurons. Glutamate- learning and memory
GABA- inhibitory- neural brake.
Plasticity- neurons are able to make new connection and strengthen old ones. The brain especially can adapt or modify itself...
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