Neurons & Nervous System

Development – Genes; ~25,000 in a fertilized egg

Structure - ~ 3 lbs; fuel = glucoseglial cells (support; insulation)Neurons (brain cells)

Some Repair- no regrowth in neurons except dendrite extensions

What’s in the Central Nervous System ?

Central Nervous System (CNS)

Brain – (Made up of neurons) & Spinal CordWhat comprises a Neuron? (refer to diagram)• Cell body – • Dendrites –• Axon – • Myelin Sheath - • End bulbs – • Synapse –

Neuron

Peripheral Nervous System

Nerves outside the Brain & Spinal cord

Can regrow, regenerate & reattach

What is the Peripheral Nervous System?

What do Neurotransmitters do? Excitatory

Open up the chemical gates in organs/cells increase the response

InhibitoryBlock the chemical gates – decrease the organ response

Endorphins – Natural pain killers

ALL or NONE Law – transmission occurs from start to end in a neuron

What are Reflex Responses?

Unlearned, involuntary, protective

Afferent – SensoryAttach to the Spinal Cord

Efferent – MotorExit from the Spinal Cord

What is Phantom Limb Phenomena? Feeling Sensations from an amputated limb

? Stump Nerves? ? Spinal Cord?? Brain? (Apparently images & sensations are stored there)

How do drugs affect neurons?

Blocking reuptake of neurotransmitter

Blocking receptors

Mimicking neurotransmitters

Should Fetal Tissue Transplants be Allowed?

Allows growth of neurons in damaged areas

Parkinson’s disease – motor neuron recoveryAlzheimersMultiple SclerosisCells removed from aborted fetuses

The Brain – Structure / Function Anamolies: Which affect brain…

Anencephaly Hydrocephaly

Trisomy 21 – Down’s Syndrome

Fragile X syndrome – pinched X

Epilepsy / Stroke

How does the Theory of Evolution Relate?

Basis for much of psychology due to Darwin’s influence

How is behavior, growth, development adaptive or functional for the individual and/or species

How do we look at the brain?

MRI (Magnetic Resonance Imaging)Radio frequencies Structure

PET Scan-Positron Emission TopographyRadioactive absorption in areasFunctioning

What are the branches of the Peripheral Nervous System?

Somatic – VoluntaryIncludes afferent and efferent nerves

Autonomic – Involuntary (Automatic)Sympathetic –

Parasympathetic –

How does the Peripheral Nervous System Work?

Fight or Flight Response – triggered by Sympathetic system

Bodily reaction to threatening situation

Homeostasis –equilibrium

Autonomic Nervous System

What’s at the front of our brain?Frontal Lobes

Most evolvedAspects of EmotionExecutive FunctionsMotor Cortex **-Voluntary motor functionsBroca’s area – Production of language

What’s at the top of our brain? Parietal Lobes

Sensory information; temp & painSomatasensory Cortex

• Information on touch, limbs, pain & temperature, object recognition & remembering

** Contralateral – one side of brain controls opposite side of body

What’s at the side of our brain? Temporal Lobes Hearing/speaking words/ Writing

Primary Auditory Cortex – Auditory association area – Wernicke’s area – understanding speech and speaking coherently

What’s at the back of our brain?

Occipital LobesColors, Recognizing objects, animals,

people

Primary Visual Cortex –

Visual Association Area –

What is in the Hindbrain?

Cerebellum – “little brain” Co-ordinated motor movement

Pons - Sleep

Medulla – vital functions

Is there a correlation between Brain Size & Intelligence ?

Racial myths – only used confirming data leading to biases

Density, not structural size appears important

Are there Hemispheric Differences ?

Left Side of the BrainVerbal Language, Math, Analytical (pieces)

Right Side of the BrainNonverbal, Spatial, Holistic (combining parts into meaningful whole)

Split-brain video clip