Download File - Dr. Jerry Cronin

The Pineal Gland
The pineal gland is a small
endocrine gland
attached to the roof of the
third ventricle – it is part of
the epithalamus
– The pineal gland secretes the hormone melatonin,
which contributes to maintaining the biological clock
(seasonal and daily cycles)
• more melatonin is secreted in darkness; the pineal gland is
very developed in nocturnal animals
The Thymus gland
• The thymus gland secretes thymosin, which
promotes the proliferation and maturation of
T cells
– T cells are a type of white blood cell (lymphocyte)
that destroys microorganisms
and foreign substances
through direct
cellular contact
General Adaptation Syndrome
• The general adaptation syndrome (GAS) or
stress response refers to the consequences of
failure to respond appropriately to emotional
or physical threats, whether actual or
imagined
– Interestingly, stressful situations can be events
normally considered to be “good”, as well as bad
• for instance, a marriage can be as stressful as a
divorce, a birth as stressful as a death, etc.
General Adaptation Syndrome
• It is impossible to remove all of the stress from our
everyday lives, and some levels of stress actually help
us perform well and be productive. Regardless, the
body’s homeostatic mechanisms attempt to
counteract stress, and maintain a constant internal
environment whenever possible
– If stress is extreme, unusual, or long lasting, the normal
mechanisms may not be enough, and they may elicit a
series of changes called the stress response or GAS
General Adaptation Syndrome
• There are three stages to a prolonged stress
response: alarm reaction, resistance reaction,
and exhaustion
– The alarm reaction is the short-lived fight-orflight response initiated by the hypothalamus and
mediated by the sympathetic division of the ANS
• it brings huge amounts of glucose and oxygen to the
brain, the lungs, and skeletal muscles
• the RAAS is also activated to maintain blood volume
and BP
THE ALARM REACTION
(Interactions Animation)
• The Alarm Reaction
You must be connected to the internet to run this animation
General Adaptation Syndrome
• The three stages to the GAS continued…
– The resistance reaction is initiated in large part
by hypothalamic releasing hormones and is a
longer-lasting response. The release of high levels
of cortisol and thyroid hormones assures that the
tissues of the body can sustain necessary
metabolic needs
General Adaptation Syndrome
The alarm reaction leads to a resistance response.
General Adaptation Syndrome
• The three stages to the GAS continued…
– Exhaustion occurs when the body’s reserves
become so depleted that they cannot sustain the
resistance stage
• Prolonged exposure to high levels of cortisol and other
hormones causes wasting of muscle, suppression of the
immune system, ulceration of the GI tract, and failure
of pancreatic beta cells… disease often ensues
THE GAS
(Interactions Animation)
• General Adaptation Syndrome
You must be connected to the internet to run this animation
End of Chapter 18
Copyright 2012 John Wiley & Sons, Inc. All rights reserved.
Reproduction or translation of this work beyond that permitted in
section 117 of the 1976 United States Copyright Act without express
permission of the copyright owner is unlawful. Request for further
information should be addressed to the Permission Department,
John Wiley & Sons, Inc. The purchaser may make back-up copies for
his/her own use only and not for distribution or resale. The
Publisher assumes no responsibility for errors, omissions, or
damages caused by the use of these programs or from the use of
the information herein.