by Miller & Levine
[complete Table of Contents]
the pull-down menu to jump to any of the Book's 40 Chapters:
Is your brain telling you the truth?
Are these circles bumps? Or are they depressions?
(You can find the answer in the Hughes
Foundation Booklet on the Senses)
In early editions of the Dragonfly
book, Figures 35-6 and 35-7 and the description of The Nerve Impulse on
pages 898-899 were a bit confusing. I rewrote this section for clarity
in June 2002. Click Here for the revision
and copies of the both new Figures.
The Nervous System
In this chapter, students
will read about the organ systems of the human body, focusing primarily
on the nervous system. They will read about how nerve cells transmit information,
the major divisions of the nervous system, and the effects of various
types of drugs on the nervous system.
Section 35-1: Human
The eleven organ
systems of the human body work together to maintain homeostasis.
Section 35-2: The
The nervous system
controls and coordinates functions throughout the body and responds to
internal and external stimuli.
A nerve impulse
begins when a neuron is stimulated by another neuron or by its environment.
Section 35-3: Divisions
of the Nervous System
The central nervous
system relays messages, processes information, and analyzes information.
The sensory division
of the peripheral nervous system transmits impulses from sense organs
to the central nervous system. The motor division transmits impulses from
the central nervous system to the muscles or glands.
Section 35-4: The
There are five
general categories of sensory receptors: pain receptors, thermoreceptors,
mechanoreceptors, chemoreceptors, and photoreceptors.
Section 35-5: Drugs
and the Nervous System
heart rate, blood pressure, and breathing rate. In addition, stimulants
increase the release of neurotransmitters at some synapses in the brain.
down heart rate and breathing rate, lower blood pressure, relax muscles,
and relieve tension.
the sudden release of a neurotransmitter in the brain called dopamine.
natural chemicals in the brain known as endorphins, which normally help
to overcome sensations of pain.
Alcohol is a depressant,
and even small amounts of alcohol slow down the rate at which the nervous
Hughes Medical Institute publishers a marvelous booklet on the senses
a perfect complement to Section 35-4. You can use it on-line,
or download the whole booklet in PDF format: