Psychology

Welcome it is a great day to learn about the Brain

What does the Brain do?Jot down EVERYTHING your brain doesOkay list about 10 thingsWe are going to start small and go big

Neurons: The Building Blocks of the Nervous SystemNervous SystemThe electrochemical communication system of the bodySends messages from the brain to the body for movementBrings information to the brain from the sensesNeuronThe basic building block of the nervous system -- a nerve cellNeurons perform three basic tasksReceive informationCarry the informationPass the information on to the next neuronTypes of NeuronsSensoryMotorInterneuron's7Key words: Types of neurons; sensory neurons; motor neurons; interneuron's; afferent nerves; efferent nerves

SpinalCordBrainSensoryNeuronSensory NeuronsINPUT From sensory organs to the brain and spinal cordDrawing shows a somatic neuron

8Key words: sensory neurons; afferent nerves; types of neuronsGraphic from Hockenbury slides

Motor NeuronsOUTPUT From the brain and spinal cord to the muscles and glands

SpinalCordBrainSensoryNeuronMotorNeuron9Key words: Motor neurons; efferent nerves; types of neuronsGraphic from Hockenbury slides

SpinalCordBrainSensoryNeuronMotorNeuronInterneuron'sInterneurons carry information between other neurons only found in the brain and spinal cord

10Key words: interneurons; types of neuronsGraphic from Hockenbury slides

The Basic Parts of a Neuron

What are the primary parts of a typical neuron?Nervous systemNeuronsDendritesSomaAxonTerminal branches of AxonMyelin SheathThe Basic Parts of a Neuron

Parts of the Neuron

A. DendritesThin, branching fibers lined with receptors at which the dendrite receives information from other neurons.

Parts of the Neuron - Dendrites

B. Cell Body/SomaContains the nucleus and other parts of the cell needed to sustain life

Parts of the Neuron - Soma

C. AxonCarries the message across the neuron

Parts of the Neuron - Axon

D. Myelin SheathAn insulating, fatty covering around the axon that speeds neural transmissions. Axons that are myelinated appear white. Known as white matter.

Parts of the Neuron Myelin Sheath

E. Axon Terminal ButtonsThe branched end of the axon that contains neurotransmitters

Parts of the Neuron - Terminals

Time to MoveLocate the person furthest from youGo to that personIntroduce yourself

Pick an A and DA = AxonD= Dendrite

With your partner explain the relationship between neuronsNeuron

Neuron

Neural Transmission

Neural Communication: The Neural Impulse

31Action PotentialA brief electrical charge that travels down the axon of the neuron.A neural impulseConsidered an on condition of the neuronRefractory PeriodThe recharging phase when a neuron, after firing, cannot generate another action potentialOnce the refractory period is complete the neuron can fire again

Resting PotentialThe state of a neuron when it is at rest and capable of generating an action potentialThe neuron is set and ready to fire

Neuron firing like a ToiletLike a Neuron, a toilet has an action potential. When you flush, an impulse is sent down the sewer pipe

Neuron firing like a Toilet2. Like a neuron, a toilet has a refractory period. There is a short delay after flushing when the toilet cannot be flushed again because the tank is being refilledNeuron firing like a ToiletLike a Neuron, a toilet has a resting potential. The toilet is charged when there is water in the tank and it is capable of being flushed againLike a Neuron, a toilet operates on the all-or-none principle it always flushes with the same intensity, no matter how much force you apply to the handleAll-or-None PrincipleThe principle that if a neuron fires it will always fire at the same intensityAll action potentials are of the same strength.A neuron does NOT fire at 30%, 45% or 90% but at 100% each time it fires.Communication Between NeuronsModule 7: Neural and Hormonal Systems

SynapseThe space between the terminal buttons on one neuron and dendrites of the next neuron

NeurotransmittersChemicals contained in the terminal buttons that enable neurons to communicate. Neurotransmitters fit into receptor sites on the dendrites of neurons like a key fits into a lock.

Neurotransmitters

NeurotransmittersA chemical messenger that travels across the synapse from one neuron to the nextCan influence whether the second neuron will generate an action potential or not

Excitatory EffectA neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential (impulse)The second neuron is more likely to fire.Inhibitory EffectA neurotransmitter effect that makes it less likely that the receiving neuron will generate an action potential (impulse)The second neuron is less likely to fire.Neurotransmitters

Acetylcholine (Ach)Found in neuromuscular junctionsInvolved in muscle movementsInvolved in learning and memoryInvolved in REM sleep55Graphic, Hockenbury slides

Disruption of Acetylcholine FunctioningNerve gases and Black Widow spider venom too much ACh leads to severe muscle spasms and possible deathCigarettes nicotine works on ACh receptorscan artificially stimulate skeletal muscles, leading to slight trembling movements

56Acetylcholine - Alzheimers DiseaseDeterioration of memory, reasoning, and language skillsSymptoms may be due to loss of ACh neurons57DopamineInvolved in movement, attention, and learningReward and motivation drugs can impair this greatly

58Dopamine - problemsDopamine imbalance also involved in schizophrenia Loss of dopamine-producing neurons is cause of Parkinsons disease

59Parkinsons DiseaseResults from loss of dopamine-producing neurons in the substantia nigra

Symptoms includedifficulty starting and stopping voluntary movementstremors at reststooped posturerigiditypoor balance60key words: Basal ganglia; Parkinson's disease; dopamineSerotoninAffects mood, hunger, sleep, and arousalEmotional states

Serotonin ProblemsInvolved in depressionProzac works by keeping serotonin in the synapse longer, giving it more time to exert an effect

EndorphinsNatural opiates that are released in response to pain and vigorous exercise Positive emotions NorepinephrinePhysical ArousalFight or flight responseWorks with the sympathetic nervous systemLearning memory 64NorepinephrineProblems: depression and stress

65GABAMuscular movement; inhibition of brain activity

GABA

PROBLEMS:Undersupply linked to seizures, tremors, and insomniaAnxiety disordersGABAHuntingtons disease involves loss of neurons in striatum that utilize GABASymptoms:jerky involuntary movementsmental deterioration68EpinephrineAdrenaline Burst of Energy (small amounts in brain)Works with the endocrine system to ensure lasting energy from threats69Epinephrine problemsCan lead to chronic stress syndrome70Glutamate

Involved in memory

Glutamate

Oversupply can over stimulate the brain, producing migraines or seizuresDrugs and Chemical Interactions with Neural Transmission

Prozac blocking the re-uptake of SerotoninNeural Communication: The Neural ChainModule 7: Neural and Hormonal Systems

Receptor CellsSpecialized cells in the sensory systems of the body that can turn other kinds of energy into action potentials that the nervous system can processReceptor cells in the eye turn light into a neural impulse the brain understands.

Sensory NervesNerves that carry information to the central nervous systemConnect the sense organs to the brain and spinal cordInterneuron'sNerve cells in the brain and spinal cord responsible for processing information related to sensory input and motor output

Motor NervesNerves that carry information from the central nervous systemCarries messages from the brain and spinal cord to other parts of your bodyA Neural Chain

A Neural Chain

A Neural Chain

A Neural Chain

A Neural Chain

Most information travels from the body, up the spinal cord, is processed by the brain, sent back down the spinal cord, and then back to the body with behavior instructions. The exception to this general pathway is reflexes.Reflexes are controlled by the spinal cord without any conscious effort on behalf of the brain. Reflexes serve as primitive responses that protect our bodies from danger and help us adjust to our surroundings.

Reflex We cough, for example, when an irritant enters our windpipe and we need to expel it through our mouth. We sneeze when we need to clear our nasal air passages of irritants and allergens. We blink when danger threatens the sensitive tissues of the eye and when we need to moisten and clean the cornea. (This reflex occurs 900 times an hour!) We yawn when nerves in the brain stem find there's too much carbon dioxide in the blood.

Reflex

Spinal Cord