The Nervous System

Part One

Emily Buff, Delaney Sullivan, Brendan von Hofe, Sam Zimmerman

http://www.skooolnigeria.com/examcentre.aspx?id=270

Components of a Motor Neuron

At Rest:•Sodium-Potassium pumps that bring Potassium in and take Sodium out.

During Action Potential:•Voltage-gated channels open up during a nerve impulse, allowing Sodium Ions to flood in, increasing the inside charge. (2)

Transport Proteins and Channel Proteins

• No signals sent or received • Sodium and Potassium

• Sodium-Potassium pump always active (1&3) o arrangement of sodium and potassium create

opposite net-charges concentration gradient

• Negative Charge inside of neuron

A Neuron at Rest

A Look at the a Neuron at Rest

http://bio1152.nicerweb.com/Locked/media/ch48/48_06bMembranePotentialB-L.jpg

1. Stimulus causes sodium voltage-gated channels to open2. Sodium floods into the cell3. This signal travels down the axon, reversing the charge as it

goes (voltage reversal) 4. To improve the polarity, potassium voltage-gated channels open5. This movement brings the charge back down to the resting

potential.

Action Potential

•Myelin Sheath (made up of lipids) (3)o Prevents electrical current from being

released out of the neurono Increases the speed of the action potential

because does not allow this current to leaveo Damaged or non-existent myelin sheath →

Multiple Sclerosis.

Action Potential cont.

Action-Potential

http://scienceblogs.com/clock/wp-content/blogs.dir/458/files/2012/04/i-91bc1a5f2d248f09ffed13e377b9c940-ActionPotential.jpg

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html

• During action potential the charge changes from negative to positive inside the neuron as it travels down the axon (2&3)

→ voltage reversal • Returns to resting-potential state as negative charges replace the positive charge• Resembles a wave

Action Potential Analogy

1. "Animation: The Nerve Impulse." Animation: The Nerve Impulse. N.p., n.d. Web. 6 Nov. 2013. <http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/

animation__the_nerve_impulse.html>.

2. "Neuroscience For Kids." - action potential. N.p., n.d. Web. 5 Nov. 2013. <http://faculty.washington.edu/chudler/ap.

3. Starr, Cecie, and Ralph Taggart. "Information Flow and the Neuron."Ecology and behavior [from] Biology, the unity and diversity of life, ninth edition. Pacific Grove, CA: Brooks/Cole, 2001. 574-579. Print.

References