What part of your body makes the most noise? Your mouth? Clapping your hands or stomping your feet? Imagine that we plugged your body into a stereo or speaker system; would we hear anything? Where would we plug the cord in? Today you will learn how your nervous system can actually make a sound if you “plugged it in.”
It’s Electric!
The nervous system controls and responds to body functions and directs behavior. Each neuron (nerve cell) communicates with many other neurons to share information. The brain is a key component of the nervous system and is the body’s most complex organ—it contains a hundred billion nerve cells and we use them all! Your brain is a network of neurons that need to communicate with each other in order for your brain to function. The brain influences and is influenced by all other body systems so it needs to be able to communicate with the nerves in the rest of your body. When you stub your toe, do you feel it right away? How do nerves communicate so quickly?
Neurons communicate using electrical and chemical signals. Chemical transmission occurs when neurotransmitters pass between nerve cells. Neurotransmitters are chemicals that send information from one nerve cell to another. The synaptic gap is an area between neurons that allows neurotransmitters to pass between neurons.
Inside of a single neuron, the body uses another method as well: electrical transmission. Sensory stimuli are converted into electrical signals and electrical signals in muscles cause contraction and movement. Neurons use electrical signals called action potentials to send information within a cell. Action potentials are electrical signals carried along neurons. These electrical signals cause neurotransmitters to be released at the end of a neuron, which cross the synapse to the next neuron.
Do you think it is possible to hear the nervous system’s electrical signals from a speaker? Turns out you can! In this lab investigation, you are going to learn about communication within the nervous system by seeing and hearing action potentials (“spikes”) in a cockroach. Humans have a complex nervous system that evolved from a simpler one. We can learn about the human nervous system by studying simpler animals, including cockroaches.
Electrical Communication in the Cockroach Nervous System
As part of this activity, you will see if cayenne pepper affects the electrical communication in the cockroach nervous system. You will use a device called a SpikerBox. A SpikerBox is a “bioamplifier” that allows you to hear the spikes (action potentials) of live neurons in a cockroach’s leg.