Immune System Flashcards
What is the immune system?
Body’s defence mechanism
Response to invasion of foreign substances
Functional components of the immune system?
(Doesn’t need to be in order)
Primary-thymus,bone marrow
Secondary- Tonsils,adenoids, spleen, Peterson patches, appendix
Lymphoid
Lymphocytes
Antibodies
Macrophages
What is an adenoid?
Lymph nodes located in the throat and behind the nose
What is the Thymus?
Behind the sternum and between lungs
only active until puberty
involved in training and development of T cells
What is Peterson patches?
Aggregations of lymphoid tissue usually found in the lowest part of the small intestine (ileum)
Major functions of the immune system?
Protects body against foreign organisms
Maintains homeostasis by eliminating damaged cells
Battles infections
What is Immunocompetent?
Appropriate Response to an antigen; maintenance of homeostasis
Vs immunoincompetence (immunocompromised)
Inappropriate immune system responses?
Allergies-Excessive response
Immunodeficient (ex: AIDS) - inadequate response
Autoimmune(ex: Systematic Lupus)- Misdirect response to ones own tissues
Transplant Rejection- Attack to beneficial foreign tissues
T-cell and B -cell formation
Bone marrow= B cell
Thymus= T cell
T lymphocyte cells include:
Cytotoxic C cells: Destroys virus-infected cells or tumor cells
Helper T Cells: stimulate B cells and activate Cytotoxic T cells and produce more antibodies
Suppressor T cells: moderate immune response by inhibiting B and T cells
Memory T cells: are reactivated only by reposture to previous antigen
B lymphocyte cells include:
Remaining stem cells develop into B cells
B cells produce antibody-mediated immunity, protects body against bacterial and viral infections
Memory B cells: reactivated only by re-exposure to previous antigen
Plasma cells: Secrete antibodies that attach to antigens
Main difference between B & T cells?
B cells attack invaders outside cell VS
T cells attack invaders inside the cell
Immunodeficiency diseases?
B cell deficiency- more prone to bacterial infections
T cell deficiency- more prone to fungal & viral infections
Some conditions are genetic and present at birth or acquired
Etiology of acquired immunoincompetence: bacterial or viral insult; malnutrition; exposure to radiation or certain drugs
Severity depends on type of cells affected
What is AIDS?
Progressive impairment of the immune system caused by HIV
Affects many organ systems
Diagnosis: presence of HIV antibodies in the blood ( Common test- ELISA, confirmation- Western blot)
Etiology: HIV attacks helper T lymphocytes; reduces cell-mediated immunity, attacks nervous system directly
How is AIDS spread?
Direct contact of blood or semen
Transmitted through blood and blood products
Infants of mothers who are infected contract in utero;
Sharing needles
