Brain Cells and Brain Chemicals
Overview
Students will be given an overview of how brain cells work, and how they use electricity and chemicals to send signals. The implications of these processes on mental illnesses will be explored.
Topic(s) | Cell biology, Neurochemistry |
Time | 1-2 hours |
Teaching Outcomes
- Understand that brain cells are discrete units that communicate using a combination of electrical and chemical signals
- Describe the functional implications of these processes
- Understand the role of so-called “brain chemicals” in some of the processes that underlie mental illnesses
Theory and Background Information
Brain Cells
Our bodies are made up of trillions of tiny individual units called cells. Similar to people having different occupations, the cells that make up different organs have different jobs to do - some are responsible for making our hearts beat, some help us absorb the food we eat, and some help us see, for example. Above is a “eukaryotic,” or animal cell. Cells have many components which are outside of the scope of this document; CELLS alive! can allow you and your students to investigate the roles of different cellular components in how cells work.
Organs are collections of cells which work together to accomplish a common goal, such as pushing blood around your body (the heart) or helping us filter out toxins (the liver). Cells with different jobs tend to be specialized; there are big differences between the ways that skin cells and brain cells look.
Brain cells, also called neurons, contain all of the parts of a cell needed to allow them to function, and are specially adapted to carry information within the brain and throughout the body. Neurons act like Internet cables running between buildings, carrying information to and from organs to our brain, just like our computers send and receive information to other computers or servers via the Internet.
Neurons use electricity to communicate, just like the electricity that powers our lights and cell phones. Like computers, neurons use “on” or “off” (that is, 1 or 0) to send information. These signals are called action potentials. Special biological machines allow for this type of communication, and in fact these processes make up a sizable portion of the total energy our bodies use!
Action potential signals start at the dendrites of a neuron, which look like the branches of a tree. These travel from the dendrites to the cell body, where signals are then sent down the axon, or the long tail-like extension from the neuron. The below image illustrates the nature of this movement; clicking on it will lead to an animated version.
An aside: local anesthetics If you’ve ever had a local anesthetic or dumbing cream/ointment applied, you may know that you lose most of the feeling in that area. These creams contain drugs which interrupt the ability for neurons to fire, not allowing the electrical signal neurons send down their axons to reach the end of the axon. Doctors and dentists use them to make some procedures hurt much less, as the neurons which send pain information can no longer work. |
Neurochemicals
When action potentials reach the end of a neuron, neurons release brain chemicals known as neurotransmitters. Neurotransmitters sent from one cell’s axon will travel and attach to its related receptor on a neighbouring cell’s dendrite. (Think of this relationship like a lock and key - the neurotransmitters are like keys which attach to different locks on cells, which can open the cell up to communicate with a neighbouring cell.) Sometimes multiple cells’ axons attach onto a single cell’s dendrite. In this way, individual neurons are able to act as small computers, taking in the signals from multiple axons and returning a single output, and indeed this is how our brains process information.
Different types of neurotransmitters are like different signals to the neurons they attach onto: some neurotransmitters tell the next cell to fire, and others tell the next cell not to fire, and further others serve assistive roles.
Changes in the way the brain makes, uses and inactivates neurotransmitters are crucial to our understanding of many mental illnesses, but are not is only factor to consider. Often times the media portrays mental illnesses as simply the result of problems with brain chemicals (i.e. too many or not enough). This fails to account for the impact that peoples’ lived experiences have on their experiences of mental illness.
Inversely, the role that neurotransmitters play in how we mentally feel cannot be understated, and should serve to reinforce the fact that people with mental illnesses cannot simply “feel better” or “smile and be happy” (in the case of depression, for example). Students should have an understanding that persons with mental illnesses cannot simply “feel better,” as they cannot force themselves to start making more of transmitters necessary to overcome their illness.
People with mental illnesses are sometimes given medicine to help regulate their levels of specific neurotransmitters. These medicines help to correct the neurotransmitter levels so that they are at a healthier level. Unlike physical medical conditions such as high blood pressure, where doctors are confident that any given medication will almost always work a certain way, medications to treat mental illnesses can sometimes not work as well as needed, often requiring patients to try multiple medications. Often a combination of medication and psychotherapy is recommended to help people feel their absolute best, as doctors ans psychologists recognize that there are often other factors in addition to biological ones that contribute to mental illness.
Conclusion
Neurons use electricity to send messages to each other using neurotransmitters. Sometimes problems can occur with neurotransmitter levels, in which case a doctor may prescribe medicine to help the person feel better.
Preparations
- If access to a projector is possible, load up this interactive brain model from BrainFacts.org to show students the location of the brain regions discussed
- Access to an anatomical model brain would also suffice, but would require the educator to familiarize themselves with the locations of specific regions discussed
- Familiarize yourself with the neuroanatomical concepts provided here
Activity
- Review the above content with students. You may wish to present some of the diagrams as a presentation; we have made one for you here.
- Alternatively, allow students to explore the content here
- Hand out this document, and have the students complete it; solutions are here
- Put students into groups, and have them prepare presentations about different neurotransmitters. They can start by picking from serotonin, epinephrine (adrenaline), norepinephrine (noradrenaline), dopamine, glutamate, or GABA
- Some of the websites students come across may be difficult for them to understand. Asking your school librarian for some resources may be beneficial!
Resources: Content
Silverthorn 6
Abnormal Psych 4
Resources: Images
Cell: https://upload.wikimedia.org/wikipedia/commons/3/3e/Eukaryotic_Cell_%28animal%29.jpg
Neuron: https://upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Neuron.svg/1280px-Neuron.svg.png
Brain: https://c1.staticflickr.com/9/8055/8376271918_0ca57957fa_b.jpg
Stomach: https://pixabay.com/p-2779304/?no_redirect
Server: https://pixabay.com/p-1419138/?no_redirect
Internet Cable: https://cdn.pixabay.com/photo/2017/08/15/09/55/internet-2643340_960_720.png
Neuron with action potential: https://upload.wikimedia.org/wikipedia/commons/thumb/9/95/Action_Potential.gif/800px-Action_Potential.gif
Lightning Bolt: http://www.clker.com/cliparts/h/S/9/O/y/r/lightning-bolt-md.png
Synapse: https://upload.wikimedia.org/wikipedia/commons/8/8e/Reuptake_both.png
Tree: https://pixabay.com/en/tree-logo-nature-design-symbol-3320941/
Upright B&W Neuron: https://upload.wikimedia.org/wikipedia/commons/e/ef/Dendrite_%28PSF%29.png