Do It NOW!!!Do It NOW!!!

1.1. What is cephalization in animals?What is cephalization in animals?2. Why do you think cephalization 2. Why do you think cephalization

exists in most animal species?exists in most animal species?3.3. What kind of symmetry must exist in What kind of symmetry must exist in

animals that are cephalized?animals that are cephalized?4.4. What do you think the two major What do you think the two major

functions of the nervous system are?functions of the nervous system are?5.5. Extra credit – there is a third Extra credit – there is a third

function, do you know what it is?function, do you know what it is?

Reflex Reflex

As you watch the video, record the 5 As you watch the video, record the 5 steps of a reflex.steps of a reflex.

How the Nervous system worksHow the Nervous system works

Function of Nervous Function of Nervous SystemsSystems

•Receive information – sensoryReceive information – sensory•Process informationProcess information•ResponseResponse•Nervous systems and neurons Nervous systems and neurons

are unique to animals!are unique to animals!

CephalizationCephalization

•Most animals have their Most animals have their sensory organs and brain sensory organs and brain near the “head” end. near the “head” end.

Three Overlapping Three Overlapping FunctionFunction

• Sensory Receptors – found throughout Sensory Receptors – found throughout the body for input about the the body for input about the organisms surroundings: sight, touch, organisms surroundings: sight, touch, taste, hearing, temperature, smell,taste, hearing, temperature, smell,

• CNS – Central Nervous System: CNS – Central Nervous System: includes the brain and spinal chord. includes the brain and spinal chord. Processes infoProcesses info

• PNS – Periferal Nervous system: PNS – Periferal Nervous system: Includes all the nerves of the body not Includes all the nerves of the body not included in the CNSincluded in the CNS

PeriferalPeriferal•Motor Output: physical Motor Output: physical

responses – muscles have responses – muscles have special synapses that are special synapses that are activated by neurons to cause activated by neurons to cause movement.movement.

•Effector cells: cells that are Effector cells: cells that are stimulated by neurons, ex. stimulated by neurons, ex. Muscles or glands that Muscles or glands that respond to the signal.respond to the signal.

             

Neuron DiagramNeuron Diagram

ClaymationClaymation

• impulseimpulse

AnimationsAnimations

• Action PotentialAction Potential • SinaurSinaur Resting Potential Resting Potential • Life Wire Action PotentialLife Wire Action Potential• Good SynapseGood Synapse• SynapseSynapse

• DrugsDrugs• action potaction pot

NeurotransmittersNeurotransmitters

• SeretoninSeretonin• EpinephrineEpinephrine• GABAGABA• DopamineDopamine• NorepinephrineNorepinephrine

Eye CupEye Cup

• Found in planaria, they are the most Found in planaria, they are the most rudimentary “eye”rudimentary “eye”

• Detect light and darkDetect light and dark

Compound EyeCompound Eye

• Arthropods – insects and Arthropods – insects and crustaceanscrustaceans

• Many lensesMany lenses• Motion expertsMotion experts