Myers’ PSYCHOLOGY

Kendall Unit 2/Book Unit 3A-C

Neuroscience, Geneticsand Behavior

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

Parts of a Neuron

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

Neural Communication

Cell body end of axon

Direction of neural impulse: toward axon terminals

Signal Transmission

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End Day 1

Worksheet on parts of a neuronNeuron building activity tomorrow

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

Neural Communication

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)

Neural Communication

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

Return to Sender

Sending neurons will reabsorb excess neurotransmitters

This is called reuptake

Neural Communication

Neurotransmitter molecule

Receiving cellmembrane

Receptor site onreceiving neuron

Agonist mimicsneurotransmitter

Antagonistblocksneurotransmitter

End Day 12

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

The Sympathetic Nervous System

The Parasympathetic Nervous System

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

End Day 3