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71 terms

Micro-Bio 3 exam

chapters 15-23
STUDY
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morbidity rate
number if people affected by a disease in a given period of time in relation to total population
notifiable disease
physicians required to report occurence of thesee diseases to u.s. public health service
LD50
number of microbes in a dose required to cause death in 50% of test animals
CDC
Centers of disease control
ID50
number of microbes in a dose required to cause infection in 50% test animals
Reservoir
Source of disease organisms Human-human disease
-Animal-disease spread from animals to humans (zoonotic)
-Nonliving-primarily soil and water
Convalecence
body returnes to pre-disease state
Decline
signs symptoms subside
Illness
period with most overt signs/symptoms of immune system is unable to resolve death
Prodromal
brief period following incubation characterized by general aches and pains
Incubation
period between infection and appearence of first signs/ symptopms
Subclinical infections
infected individuals show no signs or symptoms i.e thyphoid mary: carrier for illness
Primary infections
may weaken the immune system and allow for a more serious secondary infection i.e HIV and pneumonia
-emia
pertaining to blood
Systemic/generalized
infectious organisms are spread throughout the body (chikenpox)
Local infection
infectious orgainisms are limited to a small bodily area (pink eye)
Duration: Chronic
Develops slowly; likely to reccur last for long periods of time
Duration: Acute
Rapid development lasts a short-time and is resolved
specific immunity
defense response triggered by invasion of a foreign organism
Antigen
molecule that reacts specifically with either an antibody or an antigen recepeter on a lymphocyte
Humoral
mediated by b- cells and antibody response
cell-mediated immunity
immunity involving a T-cell response
Acquired immunity
immunity developed over time in response to exposure to antigens
Natural active
results from exposure to antigens in the course of daily life
natural passive
results from antibody transfer from mother-infant
artificial active "antigens"
recieving antigen from a vaccine
artificial passive
result from injection of antibodies into the body
humoral immunity
mediated by b-cells vaccination are geared towards these cells
Activation complement
by Fc region cross-linking enhance the efficiency of phagocytosis
opsonization
antigen coated in antibodies to enhance phagocytosis
Epitiope
portion of antigen recognized by immune system. "b-cells only to recognize on epitope"
Neutralization
Viruse or toxin is prevented from binding to cell surface
B-cells
originate from stem cells located in bone marrow. upon encounter with its specific antigen a b-cell will proliferate and convert to a plasma cell circle throughtout the body waiting for antigen. b-cells become memory cells
Plasma cell
antibody "factories" which produce "only" the antibody specific for the antigen that triggered its production
Humoral immunity
works to elimate extracelluar antigens bacteria, toxins viruses B cells are responsible for Humoral immunity
Cell-mediated immunity
Dependent on activity of T cells. T-cells mature in the thymus 2 types CD4 and CD8
CD4 t-cells
helper t-cells=Th
CD8 t-cells
Cytoxic-Tc
3 types of APC
B cell dendritic cell, macophage MHC 1- presents antigen to CD8 T cells, MHC 11- presents antigen to CD4 and T cells expressed only on APC
Function of Tc Cells
MHC1 presents intracelluar antigens (derived from viruses, intracelluar bacteria) to CD8 and T cells. Any particualr CD8 T cell will only recognize one antigen Upon binding to its appropriate antigen. MHC 1 complex, CD8 T cells induce cell death in the target cell
Cytokine
Chemical messenger: Secreted cytokines may stimulate B-cells to develop into plasma cells or memory B cells (TH2) secreted cytokines may stimulate activation of macrophages and or stimulate CD8 T-cell activity (TH1)
Epidemiology
study of disease patterns in populations
communicable
transmitted from one host to another (person to person)
contagious
diseases which can spread easily from host to host
epidemic
unusually large numbers of cases in a population short period of time
sporatic
when cases occur only from time to time
endemic
constantly present in a given population
pandemic
worldwide epidemic
symptoms
subjective changes resulting from diverse (general pain, discomfort, headache
signs
measurable changes resulting from disease (inflammation, swelling, fever)
Acute
rapid development; lasts a short time and is resolved
chronic
develops slowly, likely to recur, last for long periods of time
Human reservoir
for most human diseases humans are the reservoir, and the disease is most easily controlled
Animal reservoir
diseases that are spread from animals to humans (zoonotic)
Nonliving reservoir
primarily in soil and water
Transmission
an incident in which an infectious disease is transmitted
Direct transmission
person to person
indirect transmission
fomites. (counter tops, door handles)
Droplet transmission
only for short distances influenza and pneumonia
Vehicle
Transmission of a disease through a medium such as food, water, air
Vector
animals that carry disease from one host to another, Arthropods are most important
Portal of exit
how a microbe is shed from the host
Portal of entry
how a microbe gains access to the host, mucous membrane, skin,
Paternak route
position a organisms underneath damaged skin, mucouse membrane
preferred portal of entry
for many microbes, they must enter by their preferred portal in order to cause disease
Noscomial
acquired while at the hospital
Antibiotic
produced by microbes to inhibit/kill other microbes
Selective toxicity
more toxic to microbes than humans
Paul Erlich
magic bullet, Chemotherapy, tried to find the "magic bullet" that could hunt down and destroy a pathogen without harming the infected host. Found salvarsan works on syphilis
Alexander Fleming
discovered penicillin in 1928
Selective toxicity
more toxic to microbes than humans