Myers’ PSYCHOLOGY Kendall Unit 2/Book Unit 3A-C Neuroscience, Genetics and Behavior
Dec 26, 2015
Objectives
Describe the parts of a neuronExplain how neural impulses are generatedDescribe how nerve cells communicateExplain how neurotransmitters affect
behavior Identify and describe the effects of the most
common neurotransmittersExplain how drugs affect neurotransmittersDescribe the contrasting effects of agonists
and antagonists
Biological Psychology
Biological Psychology branch of psychology concerned with the
links between biology and behavior some biological psychologists call
themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists
Neurons
The body’s information system is built from billions of interconnected cells called neurons
Neuron a nerve cell the basic building block of the nervous
system
Parts of a NeuronCell Body/Soma
Like other cells, this is the main part of the cellDendrite
Bushy, branching extensions of a neuron that receives messages and conducts impulses towards the cell body
Axon Extension of the neuron, ending in branching
terminal fibers, through which messages are sent to other neurons or to muscles or glands
Myelin (MY-uh-lin) Sheath A layer of fatty cells segmentally encasing the
fibers of many neurons Enables vastly greater transmission speed of
neural impulses
Be a Neuron!!
You are a neuron!Hold your left hand so that your fingers
are spread out but your arm is close to your body
Hold your right arm straight out to your side
Answer: Which part of you is the dendrite? Soma/cell body? Axon? Terminal buttons?
Neural Signals Neurons “hold hands” (in a sense) via action potential Neurons don’t actually touch each other; but
electrical impulses trigger other neurons, neurotransmitters, hormones, etc. These cause things to happen!
Action Potential a neural impulse; a brief electrical charge that
travels down an axon generated by the movement of positively charged
atoms in and out of channels in the axon’s membrane
Threshold the level of stimulation required to trigger a neural
impulse
Signal Transmission
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Neurons Cannot Do it Alone!
One neuron cannot do it all alone!
It takes billions of them and their “connections” to one another/”communication” with one another to make things happen
Triggers!
When a neuron has an electrical impulse it is considered “activated” or “fired up”
So…what does the electrical impulse that a neuron carries do???
It can trigger… Fire up another neuron (to carry on the
electrical impulse) through pressure, heat light, or chemical transmission
Most commonly through chemical messages
Neural Communication
Synapse [SIN-aps] junction 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
NeurotransmittersRemember - there are gaps between neurons
They “air kiss” (don’t actually touch) When an electrical impulse/action potential
reaches the end of the terminal buttons it signals the release of neurotransmitters Neurotransmitters are the “chemical messengers” Neurotransmitters cross the gap and bind to
receptor sites Neurotransmitter can only enter a receptor site
that it was made to fit – like a lock and keyUnlocks the neuron and allows the ions to
enter and that fires the new neuron and the message continues (new impulse/action potential)
I Wanna Hold Your HandYou are a neuron! Again! Get in position and remember where your right
arm, left arm, and hands goEveryone stand in a circleNow we are a chain of neurons and we are
going to pass a messageI will start…my wiggle is the messagePass it along!Let it come in your dendrite, let it pass through
your soma, wiggle through your axon and out the terminal end to the neuron next to you!
Remember – neurons are in clusters and are usually not in a line.
THE BEATLES Remasters! ___ 6. I Want To Hold Your Hand - (MONO MASTERS Vol.1) (MONO Remastered 2009)[1].mp4
Neural Communication
Neurotransmitter molecule
Receiving cellmembrane
Receptor site onreceiving neuron
Agonist mimicsneurotransmitter
Antagonistblocksneurotransmitter
A Little More on Neurotransmitters
Neurotransmitters Chemical messengers that cross the
synaptic gap/cleft between neurons They are released by the sending neuron They travel across the synaptic gap/cleft They bind to a receptor site designed for
that certain type of neurotransmitter This influence whether a new action
potential/impulse is generated in the next neuron
Drugs and Neurotransmitters Why can’t we just take neurotransmitters?
Body may stop producing the neurotransmitter in response When drug is taken away the brain would not have the
neurotransmitter which served a necessary function in the first place
Withdrawal Drugs can affect the communication at the synapse
Can excite or inhibit neural firing/activation at the synapse Agonists and antagonists
Agonists excite Mimic neurotransmitters activity or block reuptake
Antagonists inhibit Inhibit the release of neurotransmitters Or can be enough like the actual neurotransmitter that it tricks the
body or can occupy receptor sites Research in neurotransmitters leading to treatments for
schizophrenia, depression, anxiety/panic, and other disorders
Neural Communication
Neurotransmitter molecule
Receiving cellmembrane
Receptor site onreceiving neuron
Agonist mimicsneurotransmitter
Antagonistblocksneurotransmitter
Find Your Friends!
You are all being given a card/slip of paperEach card has the
name/description/characteristic of a neurotransmitter
Using page 57 in the book, your notes, and your memory you are to find your “friends” Match the name to the characteristics
The Nervous System Nervous System
the body’s speedy, electro-chemical communication system
consists of all the nerve cells of the body Neurons are the elementary components
– the smallest Lego pieces, if you will There are 2 major divisions of the
nervous system central nervous system peripheral nervous system
Central Nervous System (CNS) the brain and spinal cord
Peripheral Nervous System (PNS) the sensory and motor neurons that
connect the central nervous system (CNS) to the rest of the body (sense receptors, muscles, glands)
Axons carrying PNS info are bundled together in groups called nerves
3 Types of Neurons
Sensory neurons Sends info from body tissues and sensory
organs to the CNS’s brain and spinal cordMotor neurons
CNS send messages to the body’s tissuesInterneurons
CNS internal communication neurons
The Nervous System
Central(brain and
spinal cord)
Nervoussystem
Autonomic (controlsself-regulated action of
internal organs and glands)
Somatic (controlsvoluntary movements of
skeletal muscles)
Sympathetic (arousing)
Parasympathetic (calming)
Peripheral
Further Division
The PNS can be further divided downPNS can be divided into 4 more
branches of the nervous system Somatic nervous system Autonomic nervous system Sympathetic nervous system Parasympathetic nervous system
The Branches of the Peripheral Nervous System
Somatic Nervous System Controls the body’s skeletal muscles Voluntary Autonomic Nervous System Controls the glands and the muscles of the internal
organs (such as the heart) Automatic pilot, but can be overridden
2 sub-branches – sympathetic and parasympathetic Work together to keep a steady internal state Sympathetic Nervous System Arousing – if something alarms, enrages, or challenges
you Mobilizing body’s energy in stressful situations Parasympathetic Nervous System Calms the body, conserving its energy
More on the CNS
Almost unimaginable wiring diagram of a very complex computer
Complex circuits that allow for learning, feeling and thinking
10 of billions of neurons communicate to make all this happen
Spinal cord is the super highway of all “talking” and “communicating” Connects the PNS to the brain Ascending fibers send info up the spinal cord Descending fibers send info down the spinal
cord
The Reflex Reflex
a simple, automatic, inborn response to a sensory stimulus
A reflex involves one simple pathway
A single sensory neuron and a single motor neuron, connected by an interneuron
Knee-jerk reflex for example
Everything goes through spinal cord
Even is spinal cord severed, reflexes can still occur below where it was severed
Skinreceptors
Muscle
Sensory neuron(incoming information)
Motor neuron(outgoing information)
Brain
Interneuron
Spinal cord
Neural Networks
Neural Networks interconnected
neural cells with experience,
networks can learn, as feedback strengthens or inhibits connections that produce certain results
computer simulations of neural networks show analogous learning
Inputs Outputs
Neurons in the brain connect with one
another to form networks
The brain learns by modifyingcertain connections in response to feedback
Endocrine System
The other communication systemGlands secrete chemical messengers
called hormonesHormones start in one tissue and
travel through the bloodstream to affect other tissues, including the brain
They act on the brain and influence behavior
Hormones
Some hormones are chemically identical to neurotransmitters
This makes the nervous system and endocrine systems kindred spirits
Hormones are slower than the zippy messengers of the nervous system
Their effects outlast the effects of the neurotransmitters
Hormones influence many aspects of our lives – growth, reproduction, metabolism and mood
Functions/Locations of Endocrine Glands
Pituitary – many hormones, affect other glands
Hypothalamus – are of the brain, controls pituitary
Thyroid – metabolism Parathyroids – regulate
calcium in blood Adrenal – fight or flight Pancreas – sugar in blood Ovary/Testes – male and
female sex hormones
Specific Examples of Effects
Adrenal Glands Top of kidneys Release epinephrine and norepinephrine
aka adrenaline and noradrenalineIncrease heart rate, blood pressure, blood sugarExtra surge of energy
Pituitary Glands In the core of the brain, pea-sized Controlled by hypothalamus Influence growth Master gland – controls other glands
Endocrine and Brain/Behavior
Brain (hypothalamus) pituitary other glands hormones brain
The 2 systems work so closely together than the line between them can be blurred