Transcript (The conscious power to override the stress response is here

Managing
Stress
8E
Principles and Strategies
for Health and Well-Being
Unless otherwise noted, all
images were supplied by Brian
Luke Seaward. Credit: ©
Inspiration Unlimited. Used with
permission.
Brian Luke Seaward, Ph.D.
Chapter 3
Physiology of Stress
Image © National Cancer Institute/Photodisc/Getty Images
“To understand the stress response,
we must possess a fundamental knowledge
not only of psychology
but physiology as well.” — George Everly
Quotation reproduced from Everly Jr. et al. The Nature
and Treatment of the Stress Response. 1981; with kind
permission from Springer Science+Business Media
B.V.
Once the brain has interpreted some sensory
information as a serious threat, the body goes
into action for the purposes of survival.
Once the brain has interpreted some sensory
information as a serious threat, the body goes
into action for the purposes of survival.
Through a chain-command of neural and
hormonal events, the body prepares to fight or
flee…beginning with the central nervous system.
Once the brain has interpreted some sensory
information as a serious threat, the body goes
into action for the purposes of survival.
Through a chain-command of neural and
hormonal events, the body prepares to fight or
flee…beginning with the central nervous system.
The term “psychophysiology” refers to this
mind-body connection.
The Central Nervous System
The Central Nervous System
The Central Nervous System (CNS) consists of the brain
and spinal column while the peripheral nervous system
(PNS) comprises all neural pathways to the extremities.
The Central Nervous System
• The Neocortical Level
(The conscious power to override the stress
response is here)
The Central Nervous System
• The Neocortical Level
(The conscious power to override the stress
response is here)
• The Limbic System
(Fight or flight is activated here!)
The Central Nervous System
• The Neocortical Level
(The conscious power to override the stress
response is here)
• The Limbic System
(Fight or flight is activated here!)
• The Vegetative Level
Figure 3.1. The three levels of the human brain include
the vegetative level, the limbic system, and the
neocortical level.
© Bradford Veley, Marquette, MI
The Autonomic Nervous System
Sympathetic
Nervous System
(Stress Response)
Parasympathetic
Nervous System
(Relaxation Response)
The Autonomic Nervous System
Sympathetic
Nervous System
(Stress Response)
Parasympathetic
Nervous System
(Relaxation response)
Epinephrine
Norepinephrine
Acetylcholine
Figure 3.3. The sympathetic and parasympathetic
nervous systems. Internal organs are typically
innervated by neural fibers from both sympathetic and
parasympathetic divisions.
The Endocrine System
The Endocrine System
The endocrine system is made of many
hormonal glands. Stress triggers the pituitary,
hypothalamus, and adrenal glands. The
adrenal gland is often called the stress gland
for its role in the fight-or-flight response.
Figure 3.5. The adrenal glands sit on top of each of the
kidneys and are cone-shaped in appearance.
The Adrenal Gland
The Adrenal Gland
The adrenal gland has two parts; the medulla
and cortex. The medulla releases epinephrine
and norepinephrine. The cortex releases
corticosteroids (e.g., cortisol) which then help
prepare the body’s energy production for flight
or flight.
Figure 3.4. The physiological response to stress.
The Neuroendocrine Pathway
1. The ACTH Axis
2. The Vasopressin Axis
3. The Thyroxine Axis
The Neuroendocrine Pathway
1. The ACTH Axis
(also known as the HPA axis)
• Corticotropin Releasing Factor (CRF) is
released from the anterior hypothalamus
• Pituitary gland then releases ACTH
• ACTH travels via the bloodstream to the
adrenal gland (cortex)
• Adrenal cortex releases corticosteroids
Figure 3.6. The ACTH Axis.
The Neuroendocrine Pathway
2. The Vasopressin Axis
• Vasopressin is also known as Antiduretic
Hormone (ADH)
• Vasopressin is synthesized in the
hypothalamus but is released via the pituitary
• Acts to increase water reabsorption and
decrease perspiration for increased blood
volume
The Neuroendocrine Pathway
3. The Thyroxine Axis
• Hypothalamus triggers release of thyrotropic
hormone-releasing factor (TRF) to pituitary.
• Pituitary then stimulates release of
thyrotropic hormone (TTH) to the thyroid
• TTH allows the thyroid to release thyroxine
and triiodothryonine to increase metabolism.
Table 3.1. Pathways of the Stress Response
The Myth of Multitasking
Insomnia and
Brain Physiology
A Parable of
Psychophysiology
A Parable of
Psychophysiology
(Your body has several physiological dynamics
to ensure your physical survival)
Figure 3.7. The immediate, intermediate, and
prolonged effects of the stress response.
A Decade of Brain Research
A Decade of Brain Research
• The hippocampus and amygdala
together form conscious emotional
memories
A Decade of Brain Research
• The hippocampus and amygdala
together form conscious emotional
memories
• The hippocampus is highly sensitive
to cortisol which aids in the memory
function of stress
A Decade of Brain Research
• The hippocampus and amygdala
together form conscious emotional
memories
• The hippocampus is highly sensitive
to cortisol which aids in the memory
function of stress
• The hippocampus region is rich in
receptor sites for glucocorticoids
A Decade of Brain Research
• The amygdala is associated with
fear-based memories
A Decade of Brain Research
• The amygdala is associated with
fear-based memories
• Repeated exposure to cortisol
accelerates the aging process of the
brain and may shrink brain cells
A Decade of Brain Research
• The amygdala is associated with
fear-based memories
• Repeated exposure to cortisol
accelerates the aging process of the
brain and may shrink brain cells
• Brain cells damaged via emotional
stress appear to be irreversible
A Decade of Brain Research
• Neuroplasticity: The brain’s ability
to generate new connections to various
brains cells AND generate new cell
growth (which was previously thought
to be impossible!)
A Decade of Brain Research
• Neuroplasticity: The brain’s ability
to generate new connections to various
brains cells AND generate new cell
growth (which was previously thought
to be impossible!)
• Relaxation techniques (e.g.,
meditation) are believed to promote
neuroplasticity.
Stress Physiology:
Take Home Message
Stress Physiology:
Take Home Message
• The stress response involves a cascade of stress
hormones throughout the body.
Stress Physiology:
Take Home Message
• The stress response involves a cascade of stress
hormones throughout the body.
• Cortisol plays a huge role in the stress response.
Stress Physiology:
Take Home Message
• The stress response involves a cascade of stress
hormones throughout the body.
• Cortisol plays a huge role in the stress response.
• The strength of the “stress-hormone cocktail”
depends on the intensity and duration of stress.
Stress Physiology:
Take Home Message
• The stress response involves a cascade of stress
hormones throughout the body.
• Cortisol plays a huge role in the stress response.
• The strength of the “stress-hormone cocktail”
depends on the intensity and duration of stress.
• Repeated (chronic) stress shrinks (atrophies) brain
cells.