Neural Impacts Circuits & Disorders
Neural Impact Objectives
- Outline the basic steps of a reflex arc as well as the path information takes through nerves in a visual reaction test.
- Identify parts of the spinal cord, including the gray matter, white matter, and nerve roots.
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Demonstrate how distractions can impact focus, and describe how pain relief medications and caffeine impact the nervous system.
The simplest example of the nervous system in action is a reflex arc. This video provides an example.
In a reflex arc a sensory receptor cell is activated and its information is bundled into a sensory nerve to the spinal cord. The spinal cord sends a signal back out through a motor nerve that causes the effector to activate, and something happens, like a muscle cell contracting The brain is notified a split second later.
This model and poster illustrate a reflex arc.
A “knee jerk” response is a classic example of a reflex arc in action.
If you try this at home, be gentle, see what minimal impact is required to activate the reflex.
In a reflex arc that cause movement, small motor neurons branch into terminals that come in contact with individual skeletal muscle cells (myocytes).
In your own words, describe the steps of a reflex arc.
This cross-section of spinal cord shows the characteristic “butterfly” tissue shape. The middle brown stained section is the “gray matter” largely consisting of the neuron cell bodies. The exterior lighter section is celled “white matter” and has those neuron’s myelinated axons.
This model shows the relationship between the vertebral bones and the spinal cord.
Sensory (afferent) nerves bringing information to the spinal cord and motor (efferent) nerves bringing information out of the spinal cord are bundled into spinal “nerve roots.”
A reaction time test engages the brain and spinal cord.
If you catch something that is falling, the eye has to receive information on the object, send it to the brain, the brain has to process the information, send a signal through the spinal cord, and out motor nerves to skeletal muscle that contact so you can grab the object.
Reaction time is a fun activity to model if you have an assistant available.
Neural Impacts
We all hear about the dangers of distractions while driving and the problems associated with multi-tasking. This video demonstrates the impact of distractions.
Another impact on the nervous system is the use of over-the-counter pain relief medications. Pain relief is challenging and often involves weighing the potential risks and benefits.
Caffeine has a powerful impact on the nervous system. It is one of the most widely used “drugs” in the world.
The next section introduces the brain, including normal functioning and brain disorders.
Check your knowledge. Can you:
- outline the basic steps of a reflex arc as well as the path information takes through nerves in a visual reaction test?
- identify parts of the spinal cord, including the gray matter, white matter, and nerve roots?
-
demonstrate how distractions can impact focus, and describe how pain relief medications and caffeine impact the nervous system?
Go back to the Nervous System Page
Go forward to the Brain Page
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