First line of defense (innate immunity) - ANSPhysical barriers:
-skin
-linings of the gastrointenstinal, genitourinary, and respiratory tracts
-sloughly off of cells
-coughing and sneezing
-vomiting
-mucus and cilia
Epithelial cell-derived chemical barriers
-synthesized and secreted salivia, tears, sweats, and mucus
second line of defense - ANSInflammatory response— first immune response to injury
-caused by a variety of materials
*infection, mechanical damage, ischemia, nutrient deprivation, temperature extremes, radiation
Third line of defense - ANSadaptive immunity
adaptive immunity - ANSthe ability to recognize and remember specific antigens and mount an
attack on them
E.i. A person who has recovered from measles is protected for life against measles
Primary intention healing - ANSOccurs where the tissue surfaces have been approximated, and
there is minimal or no tissue loss—stitches after incision
Secondary intention healing - ANSWounds that require a great deal more tissue replacement
—open wounds
innate immunity (natural immunity) - ANSImmunity that is present before exposure and effective
from birth. Responds to a broad range of pathogens.
-e.i skin
Hypersensitivity - ANSAltered immunologic response to an antigen that results in disease or
damage to the most
-characterized by the immune mechanism
Four types
1. Type I- most common hypersensitivity: IgE mediated
2. Type II: tissue-specific reactions
3. Type III: immune complex mediated
4. Type IV: cell mediated
Type I - ANSIgE mediated - allergy
Against environmental antigens (allergens)
Ex peanuts, pollen, med-penicillin
,Histamine release
-H1 and H2 receptors
-antihistamines
Manifestations:
-itching, urticaria, conjunctivitis, rhinitis, hypotension, bronchospasm, dysrhthmias, GI cramps
and malabsorption
Type II - ANSIgG and IgM mediated— tissue specific
-specific cell or tissue (tissue specific antigens) is the target of an immune response
Ex hypothyroidism/Graves' disease
Type III - ANSImmune complex mediated
-antigen-antibody complexes are formed in the circulation and are later deposited in vessel
walls or extra vascular tissues
-not organ specific
-induce a massive inflammatory response
Example: serum sickness—typically affects blood vessels, joints and kidneys
Type IV - ANScell mediated and delayed
-cytotoxic T lymphocytes or producing Th1 cells
-direct killing by Tc or recruitment of phagocytic cells by Th1 cells
Examples:
-allergic contact
- dermatitis
-skin test for TB
-contact allergic reactions-poison ivy
Autoimmunity - ANSreaction of immune response to one's own tissues
-doesn't know difference from self and non-self
-body fights against itself
Breakdown of tolerance
-body recognizes self-antigens as foreign
-self-antigens not normally seen by the immune system
Example: lupus
Transmission of the HIV infection - ANSHIV
-retrovirus that selectively attacks the CD4+ lymphocytes
-transmitted from person to person through
*sexual contact
*blood to blood contact
*perinatally
-seroconversion- the point at which an infected person converts from being negative to being
positive
-window period- the time after infection and before seroconversion
, acquired immunodeficiency syndrome (AIDS) - ANSThe most advanced, and fatal, stage of an
HIV infection.
Syndrome cause by a viral disease
-HIV
-depletes the body's Th cells
-incidence
Epidemiology
-blood-borne pathogen
High risk activities include unprotected sex, anal sex and IV drug use
-heterosexual activity is most common route worldwide
-increasing faster in women than men especially in adolescents
Clinical manifestations of AIDS - ANS-initially a mild flu-like illness (acute retro viral syndrome)
-initially serologically negative-no antibodies to virus are present in the blood but the actual viral
particles are in the blood
—window period
-serologically positive by a symptomatic
-seroconversion occurs from 2 weeks to 6 months
-early stages of HIV- fever, night sweats, kaposis sarcoma
General adaption syndrome (GAS) - ANSSelye's concept of the body's adaptive response to
stress in three phases—alarm, resistance, exhaustion.
1. Alarm stage - ANSActivates SNS
-stressor triggers the hypothalamic-pituitary adrenal axis (HPA)
-activates sympathetic nervous system
-arousal of body defenses
2. Resistance/adaption stage - ANSTrip to adapt to that alarm stage
-begins with the actions of the adrenal hormones
-mobilization contributes to fight or flight
3. Exhaustion stage (allostatic overload) - ANSIf body is unable to resist against alarm stage
-occurs only if stress continues and adaption is not successful
-leads to stress-related disorders
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