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122 Cards in this Set

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Antimicrobial agents
A special group of chemotherapeutic agents used to treat diseases caused by microbes
Antibiosis
Means "against life"
Antibiotic
A chemical substance produced by microorganisms which has the capacity to inhibit the growth of bacteria and even destroy bacteria and other microbes.
Synthetic drug
a drug synthesized in the laboratory
Semisynthetic drugs
partly made by laboratory synthesis
1910
Paul Ehrlich used Salvarsan to treat Syphillis (year)
1935
Gerhard Domagk discovered prontosil, a red dye, inhibits growth of many gram-positive bacteria (year)
1936
Ernest Fourneau discovered that the sulfanilamide portion contained antimicrobial activity
Selective toxicity
Antimicrobial drug must harm the microbes without causing significant damage to the host
Toxic host damage
causes host damage
Therapeutic dosage level
successfully eliminates the pathogenic organism if the level is maintained
The Spectrum of Activity
The range of different microbes against which an antimicrobial agent acts
Broad spectrum
Agents effective against both gram positive and gram negative bacteria
Narrow spectrum
Agents effective against a small number of microbes
toxicity, allergy, disruption of normal flora
Three categories of side effects of antimicrobial agents
natural selection, chromosomal mutation, extrachromosomal resistance (R plasmids or R factors)
Microorganisms normally acquire antibiotic resistance by genetic changes (3 examples)
B-lactam ring
attaches to the enzymes that cross-link peptidoglycans and prevent cell wall synthesis. Contained within Penicillin and cephalosporin
Antimetabolites
substances that affect the utilization of metabolites and therefore prevent a cell from carrying out necessary metabolic reactions.
alteration of targets, alteration of membrane permeability, development of enzymes, alteration of an enzyme, alteration of a metabolic pathway.
5 mechanisms of microorganism resistance
Pathogen
a parasite capable of causing disease in a host
Host
any organism that harbors another organism
Mutualism
both members of the association living together benefit from the relationship
Parasitism
one organism, the parasite, benefits from the relationship, whereas the other organism, the host, is harmed by it.
Commensalism
two species live together in a relationship such that one benefits and the other one neither benefits nor is harmed
Symbiosis
mutualism, commensalism and parasitism.
Contamination, infection and disease
can be viewed as a sequence of conditions in which the severity of the effects microbes have on their hosts increases.
Contamination
Means that microorganisms are present
Infection
Refers to the multiplication of any parasitic organism within or on the host's body
Disease
A disturbance in the state of health wherein the body cannot carry out all its normal functions
Pathogenicity
The capacity to produce disease
Virulence
Refers to the intensity of the disease produced by pathogens, and it varies among different microbial species.
Animal Passage
The rapid transfer of the pathogen through animals of a species susceptible to infection by that pathogen
Attenuation
The weakening of the disease-producing ability of the pathogen.
Normal (indigenous) Microflora
organisms that live on or in the body but do not cause disease and have well-established associations with humans.
Resident Microflora
comprise microbes that are always present on or in the human body
Transient Microflora
microbes that can be present under certain conditions in any of the locations where resident microflora are found.
Infectious Diseases
caused by infectious agents such as bacteria, viruses, fungi, protozoa, helminths.
Non-Infectious Diseases
Caused by any other factor other than infectious organisms
Inherited diseases
Diseases that are caused by errors in genetic information
Congenital Diseases
Diseases that are structural and functional defects present at birth
Degenerative Diseases
Disorders that develop in one or more body system as aging occurrs
Nutrional Deficiency Diseases
diseases that lower resistance to infectious diseases and contribute to the severity of infections
Mental Diseases
can be caused by a variety of factors (emotional, psychogenic or infection)
Immunological Diseases
diseases such as allergies, autoimmune diseases, and immunodeficiencies
Neoplastic Diseases
involve abnormal cell growth that leads to harmless or cancerous tumors
Iatrogenic Diseases
diseases that are caused by medical procedures and/or treatments
Idiopathic Diseases
Diseases whos causes are unknown
Toxin
any substance that is poisonous to other organisms
Exotoxins
Soluble substances secreted into host tissues, some are enzymes
Endotoxins
part of the cell wall and are released into host tissues from gram negative bacteria
Cytopathic Effect (CPE)
in tissue culture systems, once inside a cell, viruses cause these observable changes
Productive Viral Infection
Occurs when viruses enter a cell and produce infectious offspring
Abortive Viral Infection
occurs when viruses enter a cell but are unable to express all their genes to make infectious offspring
Latent Viral Infection
a weakened immune system allows the virus to multiply
Persistent Viral Infections
involve a continued production of viruses over many months or years. May be so chronic that there are no outward signs of an infection.
Mycotoxins
Produced by certain fungi. Cause disease if ingested by humans
Helminths
Extracellular parasites that inhabit intestines or other body tissues and many release toxic waste products and antigens in their excretions
Sign
a characteristic of a disease that can be observed by examining the patient
Symptom
a characteristic of a disease that can be observed or felt only by the patient
Syndrome
a combination of signs and symptoms that occur together and are indicative of a particular disease or abnormal combination
Sequelae
even after recovery, some diseases have after-effects
Incubation Period
the time between infection and appearance of signs and symptoms
Prodromal Phase
a short period during which nonspecific, often mild symptoms appear
Prodrome
a symptom indicating the onset of a disease
Invasive Phase
a period during which the individual experiences the typical signs and symptoms of the disease
Decline Phase
the period of illness during which host defenses and effects of treatment overcome the pathogen
Covalescent Period
Tissues are repaired, healing takes place, and body regains strength and recovers.
Innate Defenses
those that act against any type of invading agent
Adaptive Defenses
respond to particular agents called antigens (e.g. viruses and pathogenic bacteria) by producing protein antibodies and activate lymphocytes
Physical Barriers
skin and mucous membranes and chemicals they secrete
Chemical Barriers
antimicrobial substances in body fluids (saliva, mucus, gastic juices, iron limitation mech)
Cellular Defenses
certain cells that engulf invading microorganisms
Inflammation
reddening, swelling and temperature to kill invading agents/inactivate their toxic products
Molecular defenses
interferon and complement that destroy or impede invading microorganisms.
Complement
Most effective non-specific molecular defense mechanism
Chemotaxis
Process that includes PRR's, cytokines and chemokines.
Pattern Recognition Receptors (PRR's)
recognize molecular patterns unique to pathogen on the phagocytic cells
Chemokines
a class of cytokines that attract additional phagocytes to the site of infection
Adherence
the ability of the phagocyte cell membrane to bind to specific molecules on the surface of the microbe
Antiphagocytic capsule
the most common means by which bacteria avoid phagocytosis
Complement System
coat microbes with antibodies to aid in phagocyte adherence
Phagosome
pseudopodia fuse and enclose microorganism within this cytoplasmic vacuole
Phagolysosome
lysosomes with digestive enzymes fuse with phagosome embrane
Inflammation
the body's defensive response to tissue damage from microbial infection
Calor
An increase in temperature (heat)
Rubor
redness
Tumor
Swelling
Dolor
Pain at infected or injured site
Cascade
a set of reactions that amplify some effect
Molecular Defenses
These defenses involve the action of interferon and complement
Interferon
Interfere with viral replication in other cells
Human Beta Defensin II
destroys pathogens by poking holes in bacterial membranes (on skin)
Immunity
refers to the ability of the organism to recognize and defend itself against infectious agents
Susceptibility
opposite of immunity, the vulnerability of the host to be harmed by infectious agents.
Immunology
the study of adaptive immunity and how the immune system responds to specific infectious agents and toxins
Immune System
consists of various cells, especially lymphocyte, and organs such as the thymus gland that help provide the host with specific immunity to infectious agents.
Naturally Acquired Adaptive Immunity
most often obtained by having a specific disease
Artificially Aquired Adaptive Immunity
obtained by receiving an antigen by injection of a vaccine or immune system (passive)
Antigen
a substance the body identifes as foreign and toward which it mounts an immune response.
Hapten
a small molecule can act as an antigen if it binds to a larger protein molecule
Antibody
a protein produced in response to an antigen that is capable of binding specifically to the antigen.
Titer
the quantity of a substance needed to produce a given reaction.
B lymphocytes (B cells)
lymphocytes are processed and mature in tissue, referred to as bursal-equivalent tissue.
T lymphocytes (T cells)
stem cells migrate to the thymus, where they undergo differentiation into thymus-derived cells
Natural Killer Cells
found in tissues circulating in blood and nonspecifically kill cancer cells and viral-infected cells
Humoral immunity (B cells) and cell-mediated immunity (cytotoxic T cells)
Lymphocytes give rise to these two major types of immune responses
Constant regions of antibodies
determines the particular class than an immunoglobulin belongs to
Variable region of an antibody
each chain has a particular shape and charge that enable the molecule to bind to a particular antigen
IgG
the main class of antibodies that is found in the blood and accounts for as much as 20% of all plasma proteins
IgA
class of antibodies that occur in small amounts in blood and larger amounts in body secretions
IgM
class of antibodies that are found as a monomer on the surface of B cells and is secreted as a pentamer by plasma cells
IgE
class of antibodies that have a special affinity for receptors on the plasma membranes of basophils in blood or mast cell tissues. Present in patients with allergies.
IgD
class of antibodies that are found mainly on B cell membranes
Active Immunization
the process of inducing active immunity. Can be conferred by administering vaccines or toxoids.
Vaccine
a substance that contains an antigen to which the immune system responds
Toxoid
an inactivated toxin that is no longer harmful but retains its antigenic properties.
Antisera
antibodies that are found in the serum and are introduced into an unprotected individual.
Immunological Disorder
a condition that results from an inappropriate or inadequate immune response
Hypersensitivity
the immune system reacts in an exaggerated or inappropriate way to a foreign substance.
Transfusion Reaction
when matching antigens and antibodies are present in the patients blood at the same time.
Sensitization
when an Rh-negative woman carries an Rh positive fetus and produces anti-Rh antibodies if it again encounters with the Rh antigen
Granulomatous Hypersensitivity
most serious and usually occurs when macrophages have engulfed pathogens but have failed to kill them.