Neural Circuits
Neural Circuits Objectives
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Outline the basic steps of a reflex arc, including how a signal travels through the nervous system is a “knee jerk” response.
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Identify parts of the spinal cord, including the gray matter, white matter, and nerve roots.
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.”
Educational toys and memorable analogies make learning anatomy a lot more fun.
The next section describes different impacts on the nervous system
Check your knowledge. Can you:
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outline the basic steps of a reflex arc, including how a signal travels through the nervous system is a “knee jerk” response?
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identify parts of the spinal cord, including the gray matter, white matter, and nerve roots?
Go back to the Neurons Page
Go forward to the Neural Impacts Page
Nervous System Lecture Guide Contents
The material from this guide and corresponding lecture is assessed on the weekly quiz.
Back to Module 6
This week’s overview
This Guide
Nervous System
