What are the four mechanisms of transmission?
2. Direct Contact
What does the portal of entry rely on?
transmission and onset of disease may depend on number of organisms absorbed
What is penetration?
disruption in the integrity of the body's surface barrier
What is direct contact?
especially for sexually transmitted infections such as gonorrhea, syphilis, chlamydia, and herpes, for which exposure of uninfected membranes to pathogens occurs during intimate contact
What is ingestion?
contaminated food and water
What is inhalation?
(not in italicized) bacterial pneumonia
What are the stages of infection/ disease?
1. incubation period
2. Prodromal stage
3. Acute stage
4. convalescent period
What is the incubation period?
phase during which the pathogen begins active replication without producing recognizable symptoms in the host
What is the prodromal stage?
The initial appearance of symptoms
what is the acute stage?
period during which the host experiences the maximum impact
What is the convalescent period?
containment of infection; resolution of associated symptoms (when you start to feel better)
What is the difference between endotoxin or exotoxin?
Exotoxins: proteins released from the bacterial cell during growth; activates inflammation in the host cell; they damage or kill host cells (ex: botulism)
Endotoxins: complex molecules int he cell wall of gram-negative bacteria; activate regulatory systems; inflammation
What is the difference between yeast and mold?
Yeast: grow on the skin and mucous membranes and gastrointestinal tract and are capable of growth of wider range of temperatures. too many antibiotics cause over growth of yeast
Molds: CANNOT GROW INSIDE WARM BODY: ringworm, athlete's foot, and jock itch, are collectively called superficial mycoses
New and emerging infectious disease are occurring because
people are exposed to more sources of infection because of INTERNATIONAL TRAVEL
What are some of the contributing factors to infection?
-vomiting and diarrhea are part of body's mechanical defense system to ride body of pathogen
-presence of a substance in the blood (-emia)
What is Type 1 immediate hypersensitivity?
ALLERGIC REACTION: with IgE on mast cells causing degranulation and release of large amounts of histamine
-systemic (anaphylactic) reaction
What is anaphylactic reaction?
systemic, life-threatening hypersensitivity reaction characterized by widespread vasodilation that leads to:
- fall in blood pressure
- difficulty breathing
-vascular permeability that causes swelling
-obstruction of the upper airway (laryngeal edema, angioedema)
RESULTS: from the intravascular presence of antigen introduced by injection, insect sting, or absorption across THE epithelial surface of the skin or GI mucosa
What is the treatment for anaphylactic shock?
What is type 2 antibody-mediateed hypersensitivity?
-involves antigens on red or white blood cells
-antibodies (IgG and IgM) recognize and bind to antigens on the patient's own cell surfaces, usually RBCs or WBCs
What are some examples of type 2 reactions?
mismatched blood transfusion reactions, hemolytic disease of the newborn due to ABO or Rh incompatibility and certain hemolytic
What is type three hypersensitivity?
-antigen-antibody complexes insert themselves into small blood vessels, joints, tissues, and glomeruli, causing symptoms.
-the harmful effects of type 3 are INDIRECT
-responsible for vasculitis, seen in certain autoimmune diseases.
What is type 4 hypersensitivity?
-DOES NOT INVOLVE ANTIGEN-ANTIBODY REACTION
(secrete cytokines that recruit and activate inflammatory cells)
-memory cells respond upon secondary injection of the specific antigien
What are examples of type 4 hypersensitivity?
contact dermatitis (poison ivy), TB reaction, rejection of an organ
What is a graft?
tissue, cell, or organs put into another person
What is a host or recipient?
person receiving tissue
Host vs. graft disease?
cells bearing foreign MHC antigens are transplanted, the recipient's immune system attempts to eliminate the donor cells
-t-cells and antibodies are involved and they attack vessels in graft
Graft vs. host?
cellular immune system of the transplanted tissue can attack unrelated recipient tissue
skin: rash on entire body
GI: bloody diarrhea, nausea, ab. pain
liver: painless jaundice
What are autoimmune diseases caused by?
breakdown in the ability of the immune system to differentiate between self and non-self antigens
-breakdown of humoral or cellular immune response can be mounted against host tissue or antigens, leading to localized or systemic injury
What is self-tolerance?
inability to mount an immun response against a person's own antigens. Human leukocytes (HLA) encoded by MHC genes serve as recognition markers of self for the immune system
How do you know when a person might test positive for HIV?
-their CD4+ cell counts are lowered while viral particles increase
What is the lab value for a person that is AIDS positive?
category 3: <200 cells/microliter
What is the function of a eosinophil?
What is the function of a basophil?
-exposed to something and then release histamine
What are the functions of leukocytes?
originate in the bone marrow and circulate throughout body
What is the function of monocytes?
transform into tissue macrophages that phagocytose bacteria
What are the signs and symptoms of mononucleosis?
What is CML?
chronic myelogenous leukemia
What is CML caused by?
What is the cause of Non-Hodgkin Lymphomas?
What are the s/s of NHL?
What is the patho of hodgkin lymphoma?
What are the s/s of HL?
pruritis and intermittent fevers
What is multiple myeloma?
plasma cells in the bone marrow and osteolytic bone lesions throughout the skeletal system
What is the difference in leukemias? acute vs. chronic?
Chronic: proliferation of more fully differentiated myeloid and lymphoid cells
Acute:precursor B (pre-B) or T (pre-T) lymphocytes referred to as lymphblasts