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2007-2008AP Biology
Nervous Systems
Brain Development
AP Biology
Nervous system
Central nervous system
Brain Spinal cord
Peripheral nervous system
Somatic (voluntary)
nervous system
Motor pathways
Sensory pathways
Autonomic (involuntary)
nervous system
Sympathetic division
Parasympathetic division
Sympatheticarousal & energy production“fight or flight”
Parasympatheticcalming & back to maintenance“rest & digest”
Sympatheticarousal & energy production“fight or flight”
Parasympatheticcalming & back to maintenance“rest & digest”
AP Biology
Types of neurons
dendrites
sensory neuron cell body
axon
cell body
interneuron
cellbody
motor neuron
dendrites
“associative”
AP Biology
Cephalization = Brain evolution
Cnidarian
nervenet
Simplest nervous system no control of complex actions
Simplest nervous systemno control of complex actions
More organizationbut still based on nerve nets; supports more complex movement
More organizationbut still based on nerve nets; supports more complex movement
Cephalization = clustering of neurons in “brain” at front (anterior) end of bilaterally symmetrical animalsCephalization = clustering of neurons in “brain” at front (anterior) end of bilaterally symmetrical animals
Flatworm Platyhelminthes
nerve cords
associativeneurons
Simplest, defined central nervous system more complex muscle control
Simplest, defined central nervous systemmore complex muscle control
Echinoderm
radial nervenerve
ribs
→→ where sense organs are
AP Biology
Mollusk
brain
giantaxon brain
ventralnerve cords
Arthropod
Further brain development ganglia = neuron clusters along CNS
Further brain developmentganglia = neuron clusters along CNS
increase in interneurons in brain regionincrease in interneurons in brain region
Earthworm
central nervous system
peripheralnerves
More complex brainsconnected to all other parts of body by peripheral nerves
More complex brainsconnected to all other parts of body by peripheral nerves
More complex brains in predators most sophisticated invertebrate nervous system
More complex brains in predatorsmost sophisticated invertebrate nervous system
Cephalization = Brain evolution
AP Biology
Evolution of vertebrate brain
Shark
Frog
Cat
Bird
HumanSpinal cordHind: Medulla oblongata
Optic tectumHind: Cerebellum
MidbrainFore: CerebrumOlfactory tract
Crocodile
hindbrain
↑forebrain
↑↑forebrain
↑↑↑forebrain dominant cerebrum
AP Biology
Human brain
AP Biology
Functional divisions of brainHindbrain
evolutionary older structures of the brainregulate essential autonomic & integrative functions
brainstemponsmedulla oblongatamidbrain
cerebellumthalamus, hypothalamus
AP Biology
Brainstem The “lower brain”
medulla oblongataponsmidbrain
Functionshomeostasiscoordination of movementconduction of impulses to higher brain centers
AP Biology
Medulla oblongata & PonsControls autonomic homeostatic functions
heart & blood vessel activitybreathingswallowingvomitingdigestion
Relays informationto & from higherbrain centers
AP Biology
MidbrainInvolved in the integration of sensory information
regulation of visual reflexesregulation of auditory reflexes
AP Biology
Reticular FormationSleep & wakefulness produces patterns of electrical activity in the brain
recorded as an ElectroEncephaloGram(EEG)most dreaming during REM(rapid eye movement) sleep
AP Biology
Cerebrum Most highly evolved structure of mammalian brainCerebrum divided
hemispheresleft = right side ofbodyright = left side ofbody
Corpus callosummajor connectionbetween 2 hemispheres
AP Biology
Lateralization of Brain FunctionLeft hemisphere
language, math, logic operations, processing of serial sequences of information, visual & auditory detailsdetailed activities requiredfor motor control
Right hemispherepattern recognition, spatialrelationships, non-verbalideation, emotionalprocessing, parallel processing of information
AP Biology
Cerebrum specializationRegions of the cerebrum are specialized for different functionsLobes
frontaltemporaloccipitalparietal
AP Biology
AP Biology
Limbic systemMediates basic emotions (fear, anger), involved in emotional bonding, establishes emotional memory
Amygdala involved in recognizing emotional content of facial expression
AP Biology
Simplest Nerve CircuitReflex, or automatic response
rapid responseautomated
signal only goes to spinal cord
no higher level processing
adaptive valueessential actions don’t need to think or make decisions about
blinkingbalancepupil dilationstartle
AP Biology
Eye Blink or Pain Withdrawal Reflex
Effector(muscle)
Spinalcord
InterneuronGraymatter
Whitematter
Motorneuron
Sensoryneuron
Receptorin skin
Stimulus
2007-2008AP Biology
cerebrumcerebellum
spinal cord cervicalnerves
thoracicnerves
lumbarnerves
femoral nerve
sciatic nerve
tibialnerve
Any Questions??