The Nervous System

Organization-Nervous System

- BrainStructure Meets Function

-Neuron-Synapse

Organization of the Nervous System

• CNS & PNS

Nerve Circuit

Organization of the Brain• 4 Main Parts– Brain Stem

• Basic Functions

– Cerebellum• Balance and

Coordination

– Limbic System• Emotion• Sensors

– Cerebral Cortex• Cognition and Thinking

Responding to Stimuli

Sensory Neurons– Connect the sense organs to the brain

Autonomic vs. Somatic Motor NeuronsTransmit the brain’s response to the appropriate muscles– Somatic skeletal muscles (conscious)– Autonomic smooth muscles

Sympathetic or Parasympathetic• Sympathetic—”Fight or Flight”

– Speeds up breathing and heart rate– Stops digestion and urination– Dilates Pupils

• Parasympathetic—Normal Body Maintenance– Moderates breathing and heart rate– Allows for digestion and urination– Constricts Pupils

*Why do we need these responses?*What if we are experiencing sympathetic type responses during our normal day-

to-day activities?

Functional Unit: Neuron

Multiple Sclerosis…A degenerative Disorder

• Slow loss of ability to control muscle movement.• Autoimmune• Body “eats” myelin sheath

• If myelin sheath is similar in function to insulation on wires, why is this disease so bad?

Action Potential--Communication within a Neuron!

• The change in charge that travels from the dendrite of a neuron down the axon.

• Can be represented on a graph as a nerve impluse:

Action Potential Activity

• How does the sodium potassium pump work?

• What is resting potential?• How does a nerve impulse

change charge?Website:

http://outreach.mcb.harvard.edu/animations/actionpotential.swf

Synapse--Communication between neurons!!!

• Signals can be transmitted from one nerve to another nerve or muscle.

Serotonin• An example of a neurotransmitter that affects

mood, sleep, heart rate.• Can be a cause of depression and anxiety.– Depression—too little– Anxiety—too much

What is depression?What is anxiety?Are these biological diseases?

Treating Depression

• Prozac and Zoloft are medicines used to treat depression.

• They are called selective serotonin reuptake inhibitors.

• Let’s watch the commercial and see if we can determine how it works.

http://www.youtube.com/watch?v=6vfSFXKlnO0

Depression and Treatment

• Depression medications are bandaids for a biological imbalance. What is meant by that analogy?

• How might therapy help cure depression?

• Is depression genetic? Environmental? Both?

Alzheimer’s

• Memory is caused by another neurotransmitter called acetylcholine.

• Complete the activity to see how Alzheimer’s might be caused by an imbalance of this neurotransmitter and how Aricept might treat (but not cure) Alzheimer’s symptoms.

http://www.aricept.com/learnaboutalz.htmlWatch the video that shows the biochemistry of

Alzheimers and how Aricept treatment works!

Schizophrenia

• Overstimulation of a neurotransmitter called Dopamine.

• Cocaine is a mimic of dopamine

• Treatment: Thorazine blocks receptors and stops signal!

Summary

• Be able to explain how a signal is sent from one neuron to another.

• Identify three ways to alter the signal and explain whether the signal is INCREASED or DECREASED!

Smarts and the Brain

• Does a bigger brain make you smarter?Yes and No

Within and individual human’s brainConnections matterMore than size…Active learning prunesconnections!