Med-Surg: Chapter 18: Promoting Health in Patients with Immune disorders Flashcards
Immunity
body’s ability to resist infection and disease
Innate Immunity
-provides first and second lines of defense
>when the first line of defense is breached, the second line of defense is initiated
First line of Defense
-physical, biochemical, and mechanical barriers
>offer surface protection to prevent the invasion of microbes
Second line of Defense
the inflammatory response
-initiated to prevent and/or limit infection, clean out the debris of dead cells, and initiate tissue healing
Adaptive (acquired) Immunity
Third line of defense
- natural exposure (which will make antibodies in the body)
- infection
- transfer of maternal antibodies
> artificial exposure
- vaccines
- infusion of immune serum globulin
> is specific
protects by cellular-mediated (T cell) and humoral-mediated (B-cell antibodies) mechanisms
The Immune System When Competent
immune system wards off the penetration of foreign microbes and the proliferation of abnormal or malignant cells
The Immune System when Incompetent
the failure can lead to allergies, infection, cancer, and autoimmune and immunodeficiency disorders
Lymphatic System
-network of vessels that transports excess interstitial fluid that has not been reabsorbed (lymph fluid) back to the bloodstream, helping to maintain fluid balance
>system contains thousands of lymph nodes located superficially and deep within the tissues near the lymphatic vessels
Lymphatic System: Lymph Nodes
small glandular structures that house macrophages, lymphocytes, and monocytes that filter and phagocytize microorganisms and other invading particles from circulating lymphatic fluid
>this filtering prevents unwanted substances from reentering the bloodstream
Thymus
soft organ located within the chest cavity near the heart
- large in children
- decreases in size into adulthood
- central lymphoid organ that produces thymosin (hormone that stimulates T-cell production) and is where T-cell development takes place
Bone Marrow
within the cavities of bone
- consists of red (active) marrow and yellow (inactive) marrow
- where B and T lymphocyte formation and differentiation of B and T cells occur
- B cells stay within the bone marrow to mature
- T cells migrate to the thymus to mature and become active as regulatory T cells (suppressor T cells) or effector T cells (helper T cells and cytotoxic T cells)
Spleen
-size of a fist, located in the LUQ of abdominal cavity
-blood filter
>red pulp= filtering site for old or damaged red blood cells; can also store blood
>white pulp= houses lymphocytes and macrophages, filtering unwanted debris
-if it is removed, patient may become immunocompromised; requiring lifelong antibiotics
Tonsils
function as traps to protect against bacteria and viruses that are inhaled
Adenoids
located at nasopharyngeal border
-defend against inhaled bacteria and viruses
Peyer’s Patches
lymphoid follicles located on the mucosa of the small intestine
-known as intestinal immune sensors and defend against pathogens that gain entry to the intestinal tract
Leukocytes
White Blood Cells
- formed in the bone marrow and lymph tissue
- mature in thymus or bone marrow
- found in blood, lymphatic system, spleen, and other body tissues
- mobile units traveling through the bloodstream to defend the body against infection
5 Types of Leukocytes
-Neutrophils
-Monocytes
-Eosinophils
-Basophils
-Lymphocytes (B and T cells)
>further classified into granulocytes or agranulocytes
Granulocytes
have granules in the cytoplasm and release histamine and other substances to defend the body against foreign materials by increasing capillary permeability through vasodilatory effects and mediating the inflammatory response
>Neutrophils, basophils, and eosinophils are all phagocytic (cells that engulf bacteria and debris) granulocytes
Neutrophils
phagocytes of early inflammation that destroy bacteria
Basophils
release heparin as an anticoagulant and histamine during the early inflammatory response
Eosinophils
phagocytes that destroy allergens and combat parasitic infections
Agranulocytes
without granules in the cytoplasm
-monocytes and lymphocytes
Monocytes
agranulocyte
- presents pathogens to T cells for destruction
- develop into macrophages
Macrophages
phagocytes and initiators of the inflammatory response that digest and destroy, or phagocytize, microorganisms and other debris
-activate helper T cells by secreting signaling proteins (Cytokines), and presenting processed antigens for destruction by the T cell
Lymphocytes
active in both humoral and cell-mediated immune responses
-formed in the bone marrow
-found in lymph nodes, spleen, and thymus
-enter bloodstream through lymphatic system
>B Lymphocytes
>T Lymphocytes
>Immunoglobulins
B Lymphocytes
-involved in humoral immune responses
-mature in bone marrow
-produce antibodies, or immunoglobulins
>once B cells are exposed to a specific antigen for the first time, they proliferate and differentiate into plasma cells and memory cells
-B cells can function independently but typically require the help of T lymphocytes
Antibodies
bind with specific antigens, marking them for destruction by other components of the immune system, or directly neutralize the antigen by inhibiting an essential function necessary for its survival
Plasma Cells
secrete antibodies after the first exposure to the antigen
Memory Cells
re-stimulated by the same antigen, mount a specific antigen-antibody response, sometimes long after the initial exposure
Immunoglobulins (IgG)
or antibodies
- B cells produce
- 5 Classes: IgA, IgD, IgE, IgG, or IgM
Immunoglobulin: IgA
found in exocrine-gland secretions such as breast milk and tears
>dominant in secretory-gland secretions such as breast milk, sweat, saliva, mucus, and tears
Immunoglobulin: IgD
plays a role in B-cell activation
-located on surface of developing B lymphocytes
Immunoglobulin: IgE
allergic reactions and parasitic infections
-least concentrated
Immunoglobulin: IgG
effective against bacteria, viruses, and other toxins
- most abundant
- transported across placenta
Immunoglobulin: IgM
initial antibody produced after an infection
- largest
- first antibody produced during the primary response to an antigen
- expressed by competent B cells
T Lymphocytes
-cellular-mediated immune response
-T-cell activation occurs when macrophages present the T-cell with a phagocytized antigen
>function: elimination of cells infected by pathogens, continued activation of the inflammatory response against persistent infections, and regulation of innate and adaptive immune responses
>Cytotoxic T cells (destroy the cell)
>Suppressor T cells
>Helper T cells
-T cells are needed by B cells in order to activate the B cell
Cytotoxic T Cells
respond to foreign cells, including tumors, non-self cells, and virus-laden cells
Helper T Cells
- augment the effectiveness of the innate immune response by activating macrophages
- augment both humoral and cellular immunity through the activation of B cells to produce antibodies
- activate cytotoxic T cells and natural killer cells
Suppressor T cells
activated by helper T cells when the immune response is no longer needed
Natural Killer (NK) cells
another form of T cell
- targets virus-infected and tumor cells
- number increases as we age; helps control infections in elderly and important for successful aging
Cytokines
-interleukins (ILs)
-interferon (IFN)
-tumor necrosis factor alpha (TNFa)
>small proteins that act to regulate immune responses
Cytokines: Interleukins (ILs)
production occurs by macrophages and lymphocytes in response to the initiation of the inflammatory response
-responsible for the general enhancement or suppression of inflammation and the stimulation of leukocyte production and maturation
Cytokines: Interferons
proteins that protect against viral infections and tumor growth
-do not destroy viruses directly; they prevent the virus from infecting the surrounding healthy cells and interfere with its ability to replicate
Cytokines: Tumor Necrosis Factor Alpha
-produced by macrophages
-enhances inflammation
-involved in the regulation and production of immune cells
>Interleukins and Interferons rely on TNFa to mount an effective inflammatory response
Complement
complex system of proteins
- provides cell-killing effects for innate and acquired immunity
- activates pathogens and inflammatory response
- initiation of the complement can activate every component of the Inflammatory response
- “complement” the antibacterial function of antibodies
- complement proteins are synthesized in the liver and circulate in the bloodstream in an inactive form until activated by bacteria, viruses, fungi, tumor cells, antigen-antibody complexes, or endotoxins
Active Immunity
antibodies or T cells are produced either after natural exposure to an antigen during illness or infection or after immunization
Passive Immunity
happens when preformed antibodies or T lymphocytes are transferred from one individual to another
ex: a newborn acquires immunity from his/her mother through the placenta
ex: acquire immunity through transfusion of antibody-laden blood products
Humoral Medicated Immunity
- antibody mediated
- cell type: B lymphocytes
- defense modality: circulating antibodies
- defends against extracellular microorganisms; bacteria, viruses
Cellular-Mediated Immunity
- cellular mediated
- Cell type: T lymphocytes
- defense modality: cell-to-cell contact
- defends against intracellular microorganisms: fungi, viruses, bacteria, tumor and transplant antigens
Changes in The Aging Immune Response
- decline in T-cell function and antibody production when exposed to specific antigen challenges
- have increased circulating antibody levels; leading to autoimmune disorders
