Stress&Disease Flashcards
– Sources of vulnerability
• Genetics, appraisals, attributions, negative outlook, rumination, “kindling” by major life stress, type of stressor
(chronic stress, chronic illness)
depression
phobias, panic attacks, OCD
anxiety
• Sympathetic-adrenomedullary system
• Cannon’s “Fight-or-Flight” Response
• Sympathetic arousal stimulates
– medulla of the adrenal glands to secrete
catecholamines
(epinephrine and norepinephrine)
• Effects: blood pressure and heart rate increase,
constriction of peripheral blood vessels,
increased sweating
physiology of stress - SAM
• Selye’s General Adaptation Syndrome
• Hypothalamus releases
– Corticotrophin-releasing factor (CRF), stimulating pituitary to release ACTH (adrenocorticotropic hormone)
• ACTH stimulates the adrenal cortex to release
glucocorticoids, especially cortisol
Physiology of Stress - HPA Axis
• The surveillance system of the body:
Primary function
– Distinguish between what is “self” and what is foreign
– Attack and rid the body of foreign invaders
• Distinction between
– Innate Immunity (nonspecific immunity)
– Adaptive Immunity (specific immunity)
immune system
– Direct Transmission (e.g., genital herpes)
– Indirect Transmission (e.g., airborne influenza)
– Biological Transmission (e.g., mosquito & yellow
fever)
– Mechanical Transmission (e.g., hepatitis A; carrier)
invasion of microbe and their growth in the body 4 WAYS OF INFECTION:
- Microbe must enter body
- Number of organisms
- Virulence of organisms
- Toxigenicity of organisms
What Determines Infection?
• Incubation period
• Period of nonspecific symptoms
• Acute phase (disease is at its height)
– Fatality ORPeriod of decline during which invading organisms
are expelled
• Can have infection without symptom
course of infection (immune sys)
– Localized – Focal – Systemic • Primary infections may lead to secondary infections
• Infections may be
• Body’s resistance to injury from invading organisms – Develops naturally or artificially • Temporary natural immunity – when breast fed • Natural immunity – acquired through disease. • Artificial immunity – acquired through vaccinations/inoculations
immunity
– Drainage system of the body
– Spleen, tonsils, thymus gland are important organs
Lymphatic system’s role in immunity
– Absorb/remove/destroy foreign substances
(immune cells)
– Made up of granulocutes & agranulocytes
(including lymphocytes)
White blood cells (WBCs) or Leukocytes
– Contain hemoglobin
red blood cells (RBCs)
Clump together to block holes in vessels
– Important role in clotting
platelets
leukemia, leukopenia, and leukocytosis
Disorders Related to White Cell
Production
– Cancer of the bone marrow
– Excessive WBCs → ↓RBCs in plasma → anemia
leukemia
– Deficiency of WBCs
– Result of diseases such as tuberculosis, measles, & viral pneumonia
leukopenia
– Excessive number of WBCs
– Response to infections like leukemia, appendicitis, mononucleosis
leukocytosis
humoral mediated immunity, protect against bacteria, and prevent viral re-infection
B cells
cell-mediated immunity, Tc cells respond to specific antigens, Th cells enhance the functioning of other white blood cells, Ts cells regulate teh immune response and supress
T cells
– E.g., tonsillitis, infectious mononucleosis, lymphoma,
splenomegaly
• At one time thought to be acute problems ending
when their course had run
– Control thru hygiene may increase allergic disorders
– May trigger development of chronic disorders
• Ulcers, multiple sclerosis, Alzheimer’s, chronic fatigue syndrome
Infectious Disorders
– Rheumatoid arthritid, MS, cancer, athlersclerosis, asthma
chronic inflammation
– a specific humoral or cell-mediated immune response that attacks the body’s own tissues.
– Women more likely to be affected
-ex. certain forms of arthiritis, multiple sclerosis, lupus erythematosis
• Viral or bacterial infection often precedes onset
• Stress may aggravate
Autoimmune disorders
• Multidisciplinary field
• Focuses on interactions among
– Behavior
– Nervous system
– Endocrine system
– Immune system
• First studies focused on generalization and
classical conditioning of the immune system
– Artificial flowers; cyclosporine & saccharine
Psychoneuroimmunology
– The degree to which the immune system functions effectively
Immunocompetence
- Measuring numbers of different cells in the immune system by looking at blood samples
• Example: Counting T, B, NK cells in the blood - Assessing the functioning of immune cells
• Activation, proliferation, transformation, and cytotoxicity of cells - Measure antibody titres
• Reactivation of latent viruses & vaccination
general indicators of immunocompetence
– Indicators suggest that immune functioning
• Has been disrupted
• Has been reduced
• Immunocompromise relates to health outcomes
– Those under stress have lower levels of antibody titres after vaccination
– Psychological stress interferes with
• Healing of wounds(prolonged)
Immunocompromise
Sudden stress – changes in immune system take place quickly • To repair wounds • To prevent infections • Fight-or-flight reactions
evolution stressor
– Being called on in class
• Produces the increases in natural killer cells and large granular
lymphocytes (innate immunity)
• Decreases some measures of adaptive (specific) immunity
(short-term stressor)
• Acute effects of increasing immune cell numbers and NK
cell activity
SNS
- Reduces the number of WBCs
- Reduces functioning and release of cytokines
- Trigger apoptosis of WBCs
• HPA & cortisol release
• Down regulates immune system possibly through
neuropeptides like beta-endorphins
Cerebral cortex
• Physiological changes in response to stress
– Usually don’t serve original purpose:
short term mobilization to fight or flee
• Excessive discharge of hormones causes health problems
– Example: prolonged cortisol secretion is related to
destruction of neurons in the hippocampus
• Long term stress
– Health consequences of HPA activation may be more significant than those of SAM activation
Physiology – Long Term Effects
• Decreases in cell-mediated immunity • Elevated cortisol levels • Lowered heart rate variability • Elevated epinephrine levels • High waist-to-hip ratio • Decreased hippocampal volume • Memory problems (associated with hippocampus) • Elevated plasma fibrinogen (made by liver & helps clotting) • Elevated blood pressure
Examples of Long Term Effects
• People differ in reactivity • Reactivity – Degree of change in • Autonomic,Neuroendocrine,Immune responses – As a result of stress • Reactivity to stress can affect vulnerability to illness • Length of recovery also important
Physiology – Individual Differences
– Body’s physiological systems fluctuate to meet stressful
demands
Allostasis
– Physiological costs of chronic exposure to fluctuating neural/neuroendocrine responses from repeated/chronic stress
• This wear and tear can lead to illness
Allostatic load
– If a person has a pre-existing vulnerability
(physical or psychological), then stress may
interact with it to cause illness
Diathesis-stress model
– Hamsters had inherited heart diseases
– Stress early in the disease process: no heart
failure
– Stress later in the disease process: precipitated
heart failure
Tapp and Natelson Study of Hamsters
– Increased vulnerability to infectious diseases such as colds, flus, herpes virus infections like cold sores & genital herpes, chicken pox (Varicella-Zoster virus),
mononucleosis (Epstein-Barr virus)
– Among those already ill, stress predicts more severe illness and more cytokines
– Reactivation of latent viruses
– Onset and course of chronic diseases such as CHD,
diabetes, arthritis, autoimmune diseases
– Anticipatory stress
Stress-induced immunosuppression has been
associated with:
– Bereavement (especially those who have become depressed)
– Loneliness
– Martial disruption and conflict
(including short-term conflicts)
– Providing care for a friend or family member with a long-term illness
psychoneuroimmun:stress and interpersonal relationships=Adverse changes in immunity are associated with
– Lower levels of saliva IgA
– Lower percentages of B cells, total T cells, and TH cells
– Lower levels of natural killer cells
– High antibody titres to several viruses
Three Mile Island nuclear accident [longtermstress]
• Social support buffers the effects of stress
• Optimism and active coping strategies are
protective
• Finding benefit&personal growth are
associated with better immune system functioning
• Self-Efficacy/Personal Control are associated with less immunocompromise under stress
coping resources
- may reduce experience of stress itself
- may reduce tendency to develop depression
- may create some expectancy based central nervous sys modulation of immunologic reactivity
self efficacy and personal control
• Emotional disclosure
– Enhances health and mood in people who have suffered a traumatic event
– Results may be immunologically mediated
• Relaxation may mute effects of stress
– Research with elderly shows higher NK cell activity after relaxation intervention
interventions to enhance immunocompetence
The developing immune system may be
vulnerable to
– Stress
– Depression
– Grief
