Transcript Stress and the Immune Response

Stress and the Immune Response
Human Physiology
November 8, 2001
Presented by Stacy Coester
How does stress affect the
immune response?
3 aspects:
What is stress?
How does the immune system function?
What are the effects of stress on the immune
system?
Stress
Physical sciences:
A force exerted on a system that distorts or
alters the structure of that system.
Biological and human sciences:
A force that exerts a distorting force on a
person’s equilibrium.
Types of Stress
Physical or psychological stressors:
Physical: excessive heat or cold, tissue trauma,
prolonged heavy exercise.
Psychological: death of a spouse, divorce, personal
injury or illness.
Acute or chronic stressors:
Acute: unpleasant films, prestige or status loss.
Chronic: Sleep deprivation, social isolation.
Distress or eustress:
Distress: negative or destructive forms.
Eustress: happy or good events that evoke a stress
response.
Body’s Responses to Stress
Gastrointestinal disease
Increased risk of MI
Delayed menarche and puberty
Increased infertility
Insomnia
High blood pressure
Impaired wound healing
IMPAIRMENT OF THE IMMUNE SYSTEM!
Immune System
Protects the body from
invading disease
organisms and other
foreign bodies that do
not belong in the body
known as antigens or
pathogens.
Cells of the Immune System
Stem Cells
(in the bone marrow)
T Cells
Cytotoxic T cells
Lymphocytes
Mast Cells
Macrophages
Natural Killer Cells
B Cells
Cytokines
Helper T Cells
Plasma Cells
Immunoglobulins
Lines of Defense
Physical barriers
Skin, linings of the gastrointestinal,
genitourinary, and respiratory tracts.
Cell-mediated immune response
Phagocytosis and local inflammation
Humoral immune response
A specific response that occurs in 4 steps.
Stress and the Immune System
Immune system is affected by and affects many
other systems of the body.
Cytokines orchestrate the immune response.
Psychoneuroimmunology
Interdisciplinary field that studies the relationship
between psychology, neurology, and immunology.
Stress doesn’t cause the disease–it sets the stage
for illness.
Neuroendocrine Pathways
Hypothalamic-pituitary-adrenal (HPA) Axis
Cytokines
Hypothalamus
signals the release of CRH
Anterior Pituitary
releases ACTH
Adrenal Cortex
releases Cortisol
Decreased # of
Natural Killer Cells
and Lymphocytes
Decreased
Antibody Production
and activity of
helper T cells
Lymphoid Tissue
Atrophies
Increased rate of
Infection and tissue
damage
Decrease in the
inflammatory
response
Influence of the Sympathetic
Nervous System
Hormone secretion increased
in response to stress:
Adrenaline, vasopressin,
epinephrine, growth hormone,
and prolactin
Adrenaline is released from
the adrenal glands
Increased epinephrine levels
cause lymphocyte migration to
the skin from the bone marrow
Other Research Findings
Psychological stressors cause increased cytotoxic
T cell division which suppresses immune function.
Increased infection might be caused in part
because the physical barriers are compromised
enabling more antigens to enter the body.
Acute stressors appear to reduce the natural killer
cell activity and lymphocyte responsivity. Chronic
stressors at first cause similar results, but then
actually enhance lymphocyte proliferation and
cytotoxicity.
Stress:
The Disease of the 21st Century
Thank you!
Are there any questions or comments?