1. 2007-2008AP Biology
Nervous Systems
Brain Development

2. 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
 Sympathetic
arousal & energy production
“fight or flight”
 Parasympathetic
calming & back to maintenance
“rest & digest”
 Sympathetic
arousal & energy production
“fight or flight”
 Parasympathetic
calming & back to maintenance
“rest & digest”

3. AP Biology
Types of neurons
dendrites
sensory neuron
cell body
axon
cell body
interneuron
cell
body
motor neuron
dendrites
“associative”

4. AP Biology
Cephalization = Brain evolution
Cnidarian
nerve
net
Simplest
nervous system
no control of
complex actions
Simplest
nervous system
no control of
complex actions
More organization
but still based on nerve
nets; supports more
complex movement
More organization
but still based on nerve
nets; supports more
complex movement
Cephalization = clustering of neurons in “brain” at front (anterior)
end of bilaterally symmetrical animals
Cephalization = clustering of neurons in “brain” at front (anterior)
end of bilaterally symmetrical animals
Flatworm
Platyhelminthes
nerve cords
associative
neurons
Simplest, defined
central nervous system
more complex muscle
control
Simplest, defined
central nervous system
more complex muscle
control
Echinoderm
radial
nervenerve
ribs
→→ where sense organs are

5. AP Biology
Mollusk
brain
giant
axon brain
ventral
nerve
cords
Arthropod
Further brain
development
ganglia = neuron
clusters along
CNS
Further brain
development
ganglia = neuron
clusters along
CNS
increase in interneurons in brain regionincrease in interneurons in brain region
Earthworm
central nervous system
peripheral
nerves
More complex brains
connected to all other
parts of body by
peripheral nerves
More complex brains
connected to all other
parts of body by
peripheral nerves
More complex brains
in predators
most sophisticated
invertebrate nervous
system
More complex brains
in predators
most sophisticated
invertebrate nervous
system
Cephalization = Brain evolution

6. AP Biology
Evolution of vertebrate brain
Shark
Frog
Cat
Bird
HumanSpinal cord
Hind: Medulla oblongata
Optic tectum
Hind: Cerebellum
Midbrain
Fore: Cerebrum
Olfactory tract
Crocodile
hindbrain
↑forebrain
↑↑forebrain
↑↑↑forebrain
dominant cerebrum

7. AP Biology
Human brain

8. AP Biology
Functional divisions of brain
 Hindbrain
 evolutionary older structures of the brain
 regulate essential autonomic & integrative
functions
 brainstem
 pons
 medulla oblongata
 midbrain
 cerebellum
 thalamus, hypothalamus

9. AP Biology
Brainstem
 The “lower brain”
 medulla oblongata
 pons
 midbrain
 Functions
 homeostasis
 coordination of movement
 conduction of impulses to higher brain
centers

10. AP Biology
Medulla oblongata & Pons
 Controls autonomic homeostatic
functions
 heart & blood vessel activity
 breathing
 swallowing
 vomiting
 digestion
 Relays information
to & from higher
brain centers

11. AP Biology
Midbrain
 Involved in the integration of sensory
information
 regulation of
visual reflexes
 regulation of
auditory
reflexes

12. AP Biology
Reticular Formation
 Sleep & wakefulness produces patterns
of electrical activity in the brain
 recorded as an ElectroEncephaloGram
(EEG)
 most dreaming
during REM
(rapid eye
movement)
sleep

13. AP Biology
Cerebrum
 Most highly evolved structure of
mammalian brain
 Cerebrum divided
 hemispheres
 left = right side of
body
 right = left side of
body
 Corpus callosum
 major connection
between 2 hemispheres

14. AP Biology
Lateralization of Brain Function
 Left hemisphere
 language, math, logic operations, processing
of serial sequences of information, visual &
auditory details
 detailed activities required
for motor control
 Right hemisphere
 pattern recognition, spatial
relationships, non-verbal
ideation, emotional
processing, parallel
processing of information

15. AP Biology
Cerebrum specialization
 Regions of the cerebrum are
specialized for different functions
 Lobes
 frontal
 temporal
 occipital
 parietal

16. AP Biology

17. AP Biology
Limbic system
Mediates basic emotions (fear, anger), involved in
emotional bonding, establishes emotional memory
Amygdala
involved in
recognizing
emotional content
of facial
expression

18. AP Biology
Simplest Nerve Circuit
 Reflex, or automatic response
rapid response
 automated
signal only goes to
spinal cord
 no higher level
processing
adaptive value
 essential actions
 don’t need to think or
make decisions about
 blinking
 balance
 pupil dilation
 startle

19. AP Biology
Eye Blink or Pain Withdrawal Reflex
Effector
(muscle)
Spinal
cord
InterneuronGray
matter
White
matter
Motor
neuron
Sensory
neuron
Receptor
in skin
Stimulus

20. 2007-2008AP Biology
cerebrum
cerebellum
spinal cord cervical
nerves
thoracic
nerves
lumbar
nerves
femoral
nerve
sciatic
nerve
tibial
nerve
Any Questions??