Quantcast Two Major Subdivisions - Basic Human Physiology

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
(1) The various hollow organs of the body whose walls have smooth muscle
tissue in them. Examples are the blood vessels and the gut.
(2) The glands.
b. The visceral organs are innervated by the ANS. This results in a "visceral
motor system." For most of us, the control of the visceral organs is automatic, that is,
without conscious control. However, recent research demonstrates that conscious
control of some of the visceral organs is possible after proper training.
The ANS is organized into two major subdivisions--the sympathetic and the
parasympathetic nervous systems.
a. The neurons of the sympathetic nervous system originate in the thoracic and
lumbar regions of the spinal cord. Thus, it is also known as the thoraco-lumbar outflow.
b. Some of the neurons of the parasympathetic nervous system originate in
nuclei of the brainstem. Others originate in the sacral region of the spinal cord. Thus,
the parasympathetic nervous system is also known as the cranio-sacral outflow.
c. In the ANS, there are always two neurons (one after the other) connecting
the CNS with the visceral organ. The cell bodies of the second neurons form a
collection outside the CNS, called a ganglion. Processes of these postganglionic
neurons extend to the visceral organs. Those processes going to peripheral visceral
organs are included with the peripheral nerves.
Under ordinary circumstances, the sympathetic and parasympathetic nervous
system have opposite effects upon any given visceral organ. That is, one system will
stimulate the organ to action, and the other system will inhibit it. The interplay of these
two systems helps visceral organs to function within a stable equilibrium. This tendency
to produce an equilibrium is called homeostasis.
Under conditions of stress, the sympathetic nervous system produces a
"fight-or-flight" response. In other words, it mobilizes all of the energy producing
structures of the body. Simultaneously, it inhibits those structures that do not contribute
to the mobilization of energy. For example, the sympathetic nervous system makes the
heart beat faster. Later, as equilibrium is restored, the parasympathetic nervous system
slows the heart down.

Medical News
EU regulator: Morning-after pill OK for all women
(AP)—The European Medicines Agency says a commonly used morning-after pill...
Frozen blueberries pack more powerful antioxidant punch
Blueberries pack a powerful antioxidant punch, whether eaten fresh or...
Scientists identify the flavour that helps us eat less
The flavour that gives food its "deliciousness" could also be...
GSK asks European regulator to OK malaria shot
(AP)—Pharma giant GSK said Thursday it is submitting its malaria...
Australia's ageing population poses budget risks
Australia's public and private economy-wide deficit could blow out to...
Experts to combat the potential 'health catastrophe' of deadly tuberculosis among people with diabetes
New research aims to estimate the benefits of different ways...
New methods of detecting Salmonella in pork meat processing
Infections caused by foodborne microorganisms are an increasing public health...
Showers may be linked to Crohn's disease say researchers
Humans may be exposed to bacteria linked with Crohn's disease...
Are the motivations of a 5km runner defined by individual ability?
5.2 million US citizens participated in 5km races in 2011...
Does cycling advocacy in Australia represent a minority movement or much more?
Write or say anything publicly that is remotely critical of...
New research findings may lead to better treatment plans for HIV patients coinfected with hepatitis C
Using a combination antiretroviral therapy to treat HIV patients coinfected...
Researcher shows how stress hormones promote brain's building of negative memories
When a person experiences a devastating loss or tragic event,...
Barriers preventing post-stroke care
For stroke victims, rehabilitation is crucial to their recovery. But...
Possible breakthrough in battle against drug-resistant diseases
In the war against drug-resistant diseases and so-called "superbugs", the...
Schoolchildren not disadvantaged by part-time work
Schoolchildren who combine schoolwork with a part-time job do not...
Seeing the same GP at every visit will reduce emergency department attendance
Attendances at emergency departments can be reduced by enabling patients...
What is whisper therapy?
Consider the stress of modern life, with its cacophonous soundtrack...
Home-based rehabilitation for CVD patients
Patients who are found to suffer from cardiovascular diseases often...
New knee implant saves the ligaments
A new total knee replacement that saves all of the...
Mouth bacteria invade the gut in liver cirrhosis patients
An invasion of the gut by mouth bacteria could be...

Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +