Loading...

BIO303: Neurobiology

Unit 3: Synapses and Neurotransmitters   Returning to our example of heat sensation and the reflexes it elicits, we will now look at synapses and neurotransmitters. Synapses are the communication links between neurons or between neurons and other cells. The human brain alone contains more than 100 billion neurons, and each of those neurons contains numerous synapses, multiplying to a mind-boggling number of neural connections. This unit will first examine the two major types of synapses: electrical and chemical. Compared to electrical synapses, chemical synapses are slower, more varied, and offer signal amplification. We will also learn that, because most neurons have a number of synapses, there are also regulatory pathways that prevent signaling confusion. Lastly, we will cover neurotransmitters, agents produced by the presynaptic cell that initiate actions for the postsynaptic cell.

Unit 3 Time Advisory
This unit will take you 9.5 hours to complete.

☐    Subunit 3.1: 1.5 hours

☐    Subunit 3.2: 1.5 hours

☐    Subunit 3.3: 1.5 hours

☐    Subunit 3.4: 1.5 hours

☐    Subunit 3.5: 1.5 hours

☐    Subunit 3.6: 2 hours

Unit3 Learning Outcomes
Upon successful completion of this unit, the student will be able to:
- list the steps of an impulse being transmitted across the synaptic cleft; - compare and contrast chemical and electrical synapses; - define inhibitory and excitatory postsynaptic potentials, and demonstrate an understanding of the definition of summation of potentials; - identify the different neurotransmitter categories, and explain the unique properties of the different categories; and - compare and contrast the ionotropic and metabotropic receptor families.

3.1 Overview of Synapses   3.1.1 Presynaptic and Postsynaptic Elements   - Reading: Biologymad.com: “Nervous System – Synapses” Link: Biologymad.com: “Nervous System – Synapses (HTML)
 
Instructions: Click on the link above, then on the section titled “Synapses,” and read the contents of this webpage. This webpage also covers sections 3.3.1 and 3.3.2
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.1.2 Directionality   - Reading: Biologymad.com: “Nervous System – Synapses” Link: Biologymad.com: “Nervous System – Synapses (HTML)
 
Instructions: Click on and read the section titled: “So why bother? Why have gaps in nerves?”
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.1.3 Electrical Synapse Members   - Reading: Absolute Astronomy.com: “Electrical Synapse” Link: Absolute Astronomy.com: “Electrical Synapse” (HTML)
 
Instructions: Read the entire webpage linked above.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.1.4 Chemical Synapse Members   - Web Media: 1Lecture.com: McGraw-Hill’s “Chemical Synapse” Link: 1Lecture.com: McGraw-Hill’s “Chemical Synapse” (Adobe Flash)
 
Instructions: Watch the video linked above.

 Watching this video should take approximately 2 minutes.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

3.2 Electrical Synapse   3.2.1 Conduction Link   - Reading: Consortium on Cognitive Science Instruction: Robert Stufflebeam’s “Neurons, Synapses, Action Potential, and Neurotranmission” Link: Consortium on Cognitive Science Instruction: Robert Stufflebeam’s “Neurons, Synapses, Action Potential, and Neurotranmission” (HTML and Adobe Flash)
 
Instructions: Read the “Conduction” paragraph in the reading linked above. 
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.2.2 Gap Junctions   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 5: Electrical Synapses” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 5:  Electrical Synapses” (HTML)
 
Instructions: Read the entire webpage, exploring the hyperlinks to figures. This reading also covers section 3.2.3.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.2.3 Synaptic Delay   Note: This topic is covered by the reading under subunit 3.2.2.

3.2.4 Ion Flow   - Reading: Nature Education: Scitable’s “Ion Channel” Link: Nature Education: Scitable’s “Ion Channel” (HTML)
 
Instructions: Read the first two sections, and study figure 1 after the second paragraph.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.3 Chemical Synapses   3.3.1 Synaptic Cleft   - Web Media: Human Anatomy (Online Learning Center): “Animation: Chemical Synapse” Link: Human Anatomy (Online Learning Center): “Animation: Chemical Synapse” (Adobe Flash)
 
Instructions: Watch the linked video above. This covers sections 3.3.1 and 3.3.2.

 Watching this video should take approximately 2 minutes.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

3.3.2 Synaptic Vesicles and Neurotransmitters    Note: This topic is covered by the animation under subunit 3.3.1.

3.3.3 Quantal Transmitter Release   - Reading: The University of Texas’s Neuroscience Online: Dr. John Byrne’s “Ch 5: Mechanisms of Neurotransmitter Release: Role of Calcium in Transmitter Release” Link: The University of Texas’s Neuroscience Online: Dr. John Byrne’s “Ch 5: Mechanisms of Neurotransmitter Release: Role of Calcium in Transmitter Release” (HTML)
 
Instructions: Read the section on “Quantal Nature of Transmitter Release.” This also covers sections 3.3.4 and 3.3.5.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.3.4 Recycling of Vesicles   Note: This topic is covered by the reading under subunit 3.3.3.

3.3.5 Role of Calcium   Note: This topic is covered by the reading under subunit 3.3.3.

3.3.6 Postsynaptic Membrane Permeability Change   - Reading: Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 7: Neurotransmitter Receptor Alter Postsynaptic Membrane Permeability” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 7: Neurotransmitter Receptor Alter Postsynaptic Membrane Permeability” (HTML)
 
Instructions: Read the entire webpage linked above.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.4 Synaptic Crosstalk   3.4.1 Inhibitory Postsynaptic Potential   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 7: Excitatory and Inhibitory Postsynaptic Potentials” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 7: Excitatory and Inhibitory Postsynaptic Potentials” (HTML)
 
Instructions: Read the entire webpage, click on any embedded hyperlinks, and explore the figures. This reading also covers subunit 3.4.2.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.4.2 Excitatory Postsynaptic Potential   Note: This topic is covered by the reading under subunit 3.4.1.

3.4.3 Summation of Potentials   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 7: Summation of Synaptic Potentials” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 7: Summation of Synaptic Potentials (HTML)
 
Instructions: Read the entire webpage, click on any embedded hyperlinks, and explore the figures.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.5 Neurotransmitter (NT) Categories   3.5.1 Neurotransmitter Synthesis   - Reading: NCBI Bookshelf’ version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: Neurotransmitter Synthesis” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition“Ch 6: Neurotransmitter Synthesis (HTML)
 
Instructions: Read the entire webpage, click on any embedded hyperlinks, and explore the figures.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.5.2 Acetylcholine   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: Acetylcholine” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: Acetylcholine” (HTML)
 
Instructions: Read the entire webpage, click on the embedded hyperlinks, and explore the figures.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: Sinauer Associates, Inc., Neuroscience 4th Edition: “Animation 6.1 Neurotransmitter Pathways: Acetylcholine” Link: Sinauer Associates, Inc., Neuroscience 4th Edition: “Animation 6.1 Neurotransmitter Pathways: Acetylcholine (Abobe Flash)
     
    Instructions: Watch the animation linked above. Click on Step-Through or Narrated to begin the animation, and then follow the instructions on the webpage to work through “Synthesis,” “Distribution,” and “Pharmacology.”
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.5.3 Amino Acids   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: GABA and Glycine” and “Glutamate” Links: NCBI Bookshelf’sversion of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: GABA and Glycine (HTML) and “Glutamate (HTML)
 
Instructions: Read the both webpages in their entirety, click on any embedded hyperlinks, and explore all figures. In addition to standard amino acids like glycine and glutamate, this category also includes GABA (gamma-aminobutyric acid). GABA is a very important NT—you should know about its functions! 
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.5.4 Biogenic Amines   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: The Biogenic Amines” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: The Biogenic Amines” (HTML)
 
Instructions: Read the entire webpage, click on any embedded hyperlinks, and explore all figures. This category includes a functionally diverse but similarly-structured group comprised of dopamine, epinephrine, histamine, and serotonin. Be sure to know the differences between these molecules! 

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

3.5.5 Neuropeptides   - Reading: Neuropeptides.net: All about Neuropeptides. Link: Neuropeptides.net: All about Neuropeptides (HTML)
 
Instructions: Read the entire webpage to learn about the function, characteristics, and benefits of neuropeptides.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: Neuropeptides Figure” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: Neuropeptides Figure” (HTML)
     
    Instructions: Please review the figure of neuropeptides on this webpage.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.5.6 ATP   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: ATP and Other Purines” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 6: ATP and Other Purines” (HTML)
 
Instructions: Read the entire webpage.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.5.7 Nitric Oxide   - Reading: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 8: Second Messenger” Link: NCBI Bookshelf’s version of Sinauer Associates, Inc., Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience 2nd Edition: “Ch 8: Second Messenger” (HTML)
 
Instructions: Scroll down and read the paragraph for “Nitric Oxide.”
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.5.8 Cannabinoid   - Reading: Oxford Journals: Brain – A Journal of Neurobiology: Leslie Iversen’s “Cannabis and the Brain” Link: Oxford Journals: Brain – A Journal of Neurobiology: Leslie Iversen’s “Cannabis and the Brain” (HTML)
 
Also available in:

[PDF](http://brain.oxfordjournals.org/content/126/6/1252.full.pdf+html)  
    
 Instructions: Read the entire webpage linked above.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

3.6 Neurotrophin Receptor Families   - Web Media: Sinauer Associates, Inc: Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 4th Ed.: “Ch 5 – Ionotropic and Metatropic Receptors” Link: Sinauer Associates, Inc.: Purves, Augustine, Fitzpatrick, et al., editors’ Neuroscience, 4th Ed.: “Ch 5 – Ionotropic and Metatropic Receptors” (Adobe Flash)
 
Instructions: Click the “narrated” link, and watch the animation. This resource also covers sections 3.6.1 and 3.6.2.
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

3.6.1 Ionotropic Receptors   Note: This topic is covered by the animation linked under subunit 3.6.

3.6.2 Metabotropic Receptor Family   Note: This topic is covered by the animation linked under subunit 3.6.

  • Assessment: The Saylor Foundation’s “Unit 3 Assessment” Link: The Saylor Foundation’s “Unit 3 Assessment (PDF)

    Instructions: Complete this quiz after working through Unit 3. The questions are either multiple choice, matching, or labeling diagrams. Your answers can be checked against The Saylor Foundation’s Unit 3 Assessment Answer Key (PDF).

    Completing this assessment should take approximately 30 minutes.