PSU micro exam 3

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Five classes of lg

(IgG, IgM, IgA, IgD, IgE)

infectious dose for 50 % of a sample populatiorn

-1D50

Identify other important factors concerning the spread of disease Develop methods for controlling a disease Assemble data and graphs to outline incidence of disease

. Epidemiologists:

Cytopathic effects

. Stopping cell synthesis . Causing cell lysosomes to release enzymes . Creating inclusion bodies in the cell cytoplasm . Fusing cells to create a syncytium Changing host cell function or inducing chromosomal changes Inducing antigenic changes on the cell surface Loss of contact inhibition in the cell, leading to cancer . Producing interferons to protect uninfected cells

Subset of CD4+ cells; carry an additional CD25 molecule Suppress T cells against self; protect intestinal bacteria required for digestion; protect fetus

. T regulatory cells (Treg

immunity in most of a population

.Herd immunity:

is a competition between microbes

.Microbial antagonism (competitive exclusion)

NORMAL RANGES AND PERCENTAGES Basophils

0.5 % to 1 %

NORMAL RANGES AND PERCENTAGES Eosinophils

2 % to 4 %

NORMAL RANGES AND PERCENTAGES Lymphocytes

20 % to 25 %

NORMAL RANGES AND PERCENTAGES Monocytes

3 % to 8 %

Hypothalamus is normally set at

37 C

NORMAL RANGES AND PERCENTAGES Neutrophils

60 % to 70 %

contain an enzyme component (A part) and a binding component (B part)

A-B toxins

exotoxins

AB toxins membrane disrupting toxins superantigens genotoxins

symptoms develop rapidly but the disease lasts only a short time

Acute disease:

Acquired through infection or vaccination

Adaptive immunity:

Primary response: first time the immune system combats a particular foreign substance

Adaptive immunity:

Secondary response: later interactions with the same foreign substance; faster and more effective due to "memory"

Adaptive immunity:

defenses that target a specific pathogen

Adaptive immunity:

immunity or resistance to a specific pathogen; slower to respond, has memory component

Adaptive immunity:

Attachment of a phagocyte to the surface of the microorganism

Adherence

______on the pathogen bind to _______ on the host cells

Adhesins (ligands), receptors

carcinogenic toxin produced by Aspergillus

Aflatoxin

are leukocytes with granules in their cytoplasm that are not visible with a light microscope

Agranulocytes

analyzes a particular disease to determine its probable cause

Analytical epidemiology;

Constant (Fc) region is the stem, which is identical for a particular lg class

Antibodies

Four protein chains form a Y-shape Two identical light chains and two identical heavy chains joined by disulfide links

Antibodies

Globular proteins called immunoglobulins (Ig)

Antibodies

Variable (v) regions are at the ends of the arms bind epitopes

Antibodies

The Classical Pathway

Antibodies bind to antigens, activating C1 C1 splits and activates C2 and C4 C2a and C4b combine and activate C3 C3a functions in inflammation C3b functions in cytolysis and opsonization

the relative amount of antibody in the serum

Antibody titer

Clonal selection differentiates activated B cells into:

Antibody-producing plasma cells Memory cells

Pathogens alter their surface antigens (and antibodies are rendered ineffective)

Antigenic Variation

substances that cause the production of antibodies Usually components of invading microbes or foreign substances

Antigens:

Short peptides produced in response to protein and sugar molecules on microbes Inhibit cell wall synthesis Form pores in the plasma Broad spectrum of activity

Antimicrobial Peptides

blood-derived fluids containing antibodies

Antiserum:

antibodies against specific exotoxins

Antitoxins:

Programmed cell death Prevents the spread of infectious viruses into other cells Cells cut their genome into fragments, causing the membranes to bulge outward via blebbing

Apoptosis

Vectors

Arthropods, especially fleas, ticks, and mosquitoes

Injection vaccination (immunization)

Artificially acquired active immunity

Injection of antibodies

Artificially acquired passive immunity

bacteria in the blood

Bacteremia:

release histamine; work in allergic responses

Basophils:

pathogen reproduces in the vector, transmited via bites or feces

Biological transmission:

The Alternative Pathway

C3 present in the blood combines with factors B, D, and P on microbe surface C3 splits into C3a and C3b, functioning the same as in the classical pathway

T helper cells (TH) Cytokine signaling with B cells , interact directly with antigens Bind MHC class Il molecules on B cells and APCs

CD4*

Cytoxic T lymphocytes (CTL) Bind MHC class I molecules

CD8*

Glycocalyx around the cell wall Impair phagocytosis

Capsules

Human reservoirs

Carriers

may have inapparent infections or latent diseases

Carriers

Formed Elements in Blood

Cells and cell fragments suspended in plasma Erythrocytes Leukocytes Platelets

attacks antigens found inside cells Viruses; some fungi and parasites

Cellular immunity

Produces T lymphocytes Recognize antigenic peptides processed by phagocytic cells Mature in the thymus T cell receptors (TCRs) on the T cell surface contact antigens, causing the T cells to secrete cytokines instead of antibodies

Cellular immunity ( cell - mediated immunity )

induce migration of leukocytes

Chemokines:

Chemical signals attract phagocytes to microorganisms

Chemotaxis

The Mechanism of Phagocytosis

Chemotaxis Adherence Ingestion Digestion

symptoms develop slowly

Chronic disease:

transports microbes trapped in mucus away from the lungs

Ciliary escalator

the membrane of nucleated animal cells Identify "self

Class I MHC

on the surface of antigen-presenting cells (APCs), including B cells

Class II MHC

eliminates harmful B cells

Clonal deletion

coagulate fibrinogen

Coagulases:

breaks down collagen

Collagenase:

one organism benefits while the other (host) is unharmed

Commensalism:

one organism benefits, and the other is unaffected

Commensalism:

a disease that is spread from one host to another

Communicable disease:

Normal microbiota protect the host by:

Competing for nutrients Producing substances harmful to invading microbes Affecting pH and available oxygen

Lack of complement proteins susceptibility to infections

Complement and disease

an individual whose resistance to infection is impaired by disease, therapy, or burns

Compromised host:

diseases that are easily and rapidly spread from one host to another

Contagious diseases:

Greek, meaning cell

Cyte:

chemical messengers produced in response to a stimulus

Cytokines

Activated complement proteins create a membrane attack complex (MAC)

Cytolysis

Outcomes of Complement Activation

Cytolysis Opsonization Inflammation

are visible effects of viral infection on a cell

Cytopathic effects (CPE)

Engulf and degrade microbes and display them to T cells Found in the skin, genital tract, lymph nodes, spleen, thymus, and blood

Dendritic cells (DCs)

found in the skin, mucous membranes, and thymus; phagocytic

Dendritic cells:

inner portion made of connective tissue

Dermis:

collection and analysis of data

Descriptive epidemiology:

Protozoa Avoid host defenses by:

Digesting cells and tissue fluids Growing in phagocytes Antigenic variation

Microorganism is digested inside a phagolysosome

Digestion

requires close association between the infected and a susceptible host

Direct contact transmission:

an abnormal state in which the body is not performing normal functions

Disease:

transmission via airborne droplets less than 1 meter

Droplet transmission:

prevents microbes from entering the ear

Earwax

Diseases that are new, increasing in incidence, or showing a potential to increase in the near future Most are zoonotic, of viral origin, and likely to be vector-borne

Emerging Infectious Diseases

disease constantly present in a population

Endemic disease:

phagocytic; toxic against parasites and helminths

Eosinophils:

disease acquired by many people in a given area in a short time

Epidemic disease:

The study of where and when diseases occur and how they are transmitted in populations

Epidemiology

outer portion made of tightly packed epithelial cells containing keratin, a protective protein

Epidermis:

alkaloid toxins that cause hallucinations

Ergot

the cause of a disease

Etiology:

Capsules prevent complement activation

Evading the complement system

Proteins produced and secreted by bacteria

Exotoxins

involves a hypothesis and controlled experiments

Experimental epidemiology:

found in the liver, spleen, and red bone marrow

Ferritin:

.Abnormally high body temperature

Fever

residents in tissues and organs

Fixed macrophages

systemic infection that began as a local infection

Focal infection:

roam tissues and gather at sites of infection

Free (wandering) macrophages

Toxic metabolic products Provoke an allergic response

Fungi

serum fraction containing antibodies

Gamma () globulin:

Predisposing Factors Make the body more susceptible to disease

Gender Inherited traits, such as the sickle cell gene Climate and weather Fatigue . Age Lifestyle Nutrition . Chemotherapy

Emerging Infectious Diseases Contributing factors

Genetic recombination Evolution of new strains Widespread use of antibiotics and pesticides Changes in weather patterns

damage DNA (causing mutations disrupting cell division, and leading to cancer)

Genotoxins

serum proteins

Globulins:

leukocytes with granules in their cytoplasm that are visible with a light microscope

Granulocytes

antigens too small to provoke immune responses; attach to carrier molecules

Haptens:

Acquired while receiving treatment in a health care facility

Healthcare-Associated Infections (HAIs) Also known as nosocomial infections

control stem cells that develop into red and white blood cells

Hematopoietic cytokines:

located in red blood cells

Hemoglobin:

acute-phase proteins

Histamine Kinins Prostaglandins Leukotrienes Cytokines

analyzes relationships between microbial communities on the body and human health

Human Microbiome

Continual sources of infection

Human reservoirs Animal reservoirs Nonliving reservoirs

Produces antibodies that combat foreign molecules known as antigens B cells are lymphocytes that are created and mature red bone marrow Recognize antigens and make antibodies Named for bursa of Fabricius in birds

Humoral immunity

fights invaders outside cells Bacteria and toxins

Humoral immunity

digests polysaccharides that hold cells together

Hyaluronidase:

produced by cells in response to viral infections; cause neighboring cells to produce antiviral proteins (AVPs) that inhibit viral replication

IFN-a and IFN-B:

causes neutrophils and macrophages to kill bacteria

IFN-y:

13 % of serum antibodies

IgA

Monomer serum; dimer in secretions

IgA

Prevent microbial attachment to mucous membranes

IgA

mucous membranes, saliva, tears, and breast milk

IgA

80 % of serum antibodies

IgG

Cross the placenta; trigger complement; enhance phagocytosis; neutralize toxins and viruses; protect

IgG

In the blood, lymph, and intestine

IgG

Monomer

IgG

6 % of serum antibodies

IgM

Cause clumping of cells and viruses

IgM

First response to an infection; short-lived

IgM

Pentamer made of five monomers held with a J chain

IgM

Remain in blood vessels

IgM

ability to ward off disease

Immunity:

number of people who develop a disease during a particular time period

Incidence:

interval between initial infection and first signs and symptoms

Incubation period:

Development of Disease

Incubation period: Prodromal period: Period of illness: Period of decline: Period of convalescence:

spreads to a host by a nonliving object called a fomite

Indirect contact transmission:

invasion or colonization of the body by pathogens

Infection:

Activated complement proteins bind to mast cells, releasing histamine

Inflammation

Destroys injurious agent or limits its effects on the body Repairs and replaces tissue damaged by the injurious agent

Inflammation

defenses against any pathogen; rapid, present at birth

Innate immunity:

Cytokines produced by cells; have antiviral activity

Interferons

interfere with viral infections of host cells

Interferons (IFNs):

cytokines between leukocytes

Interleukins:

presence of toxin without microbial growth

Intoxications:

Surface proteins produced by bacteria that rearrange actin filaments of the cytoskeleton

Invasins

digest fibrin clots

Kinases:

lethal dose for 50 % of a sample population Measures potency of a toxin

LD50

drains tears; washes eye

Lacrimal apparatus:

found in milk, saliva, and mucus

Lactoferrin:

causative agent is inactive for a time but then activates and produces symptoms

Latent disease:

Membrane-disrupting toxins

Leukocidind Hemolysins Streptolysins

is used to test for endotoxins

Limulus amebocyte lysate (LAL) assay

Endotoxins

Lipid A

portion of lipopolysaccharides (LPS) of gram-negative bacteria Released during bacterial multiplication and when gram-negative bacteria die Stimulate macrophages to release cytokines Cause disseminated intravascular coagulation

Lipid A

pathogens are limited to a small area of the body

Local infection:

The Lymphatic System

Lymph, lymphatic vessels, lymphoid tissue, and red bone marrow

T cells, B cells, and NK cells; play a role in adaptive immunity

Lymphocytes:

changes characteristics a microbe due to incorporation of a prophage

Lysogenic conversion

perspiration, tears, saliva, and urine destroys bacterial cell walls

Lysozyme

resists phagocytosis

M protein

Activated by cytokines or the ingestion of antigenic material Migrate to the lymph tissue, presenting antigen to T cells

Macrophages

The Lectin Pathway

Macrophages ingest pathogens, releasing cytokines that stimulate lectin production in the liver Mannose-binding lectin (MBL) binds to mannose, activating C2 and C4 C2a and C4b activate C3, which functions the same as in the classical and alternative pathways

genes encode molecules on the cell surface

Major histocompatibility complex (MHC)

sticking of phagocytes to blood vessels in response to cytokines at the site of inflammation

Margination

arthropod carries pathogen on its feet

Mechanical transmission:

Vectors Transmit disease by two general methods

Mechanical transmission: Biological transmission:

lyse host cells by disrupting plasma membranes

Membrane-disrupting toxins

HAls result from:

Microorganisms in the hospital environment Weakened status of the host Chain of transmission in a hospital

Emerging Infectious Diseases Contributing factors (cont'd)

Modern transportation Ecological disaster, war, and expanding human settlement Animal control measures Public health failure

mature into macrophages in tissues where they are phagocytic

Monocytes:

number of people affected in relation to the total population in a given time period

Morbidity rate:

number of deaths from a disease in relation to the population in a given time

Mortality rate:

Epithelial layer that lines the gastrointestinal, respiratory, and genitourinary tracts

Mucous membranes

Portals of entry

Mucous membranes Skin Parenteral route

viscous glycoproteins that trap microbes and prevent tracts from drying out

Mucus:

both organisms benefit

Mutualism:

are produced by mushrooms and are neurotoxic

Mycotoxins

Form pores in the target cell, leading to lysis or apoptosis

Natural killer (NK) cells

Granular leukocytes destroy cells that don't express MHC class I self-antigens

Natural killer (NK) cells

Kill virus-infected and tumor cells and attack parasites

Natural killer (NK) cells

Not always stimulated by an antigen

Natural killer (NK) cells

Resulting from infection

Naturally acquired active immunity

Transplacental or via colostrum

Naturally acquired passive immunity

phagocytic; work in early stages of infection

Neutrophils:

Granulocytes

Neutrophils: Basophils: Eosinophils:

a disease that is not spread from one host to another

Noncommunicable disease:

Produce substances harmful to pathogens Alter conditions that affect pathogen survival

Normal microbiota

compete with pathogens via microbial antagonism Produce substances harmful to pathogens Alter conditions that affect pathogen survival

Normal microbiota

permanently colonize the host and do not cause disease under normal conditions

Normal microbiota

diseases in which physicians are required to report occurrence

Notifiable infectious diseases:

Distribution and composition of normal microbiota determined by many factors

Nutrients Physical and chemical factors Host defenses Mechanical factors

allows attachment to host cells

Opa protein

Promotes attachment of a phagocyte to a microbe

Opsonization

microorganism is coated with serum proteins, making ingestion easier

Opsonization:

worldwide epidemic

Pandemic disease:

one organism benefits at the expense of the other

Parasitism:

the functioning part of the tissue that is repaired

Parenchyma

Deposited directly into tissues when barriers are penetrated

Parenteral route

the development of disease

Pathogenesis:

the ability to cause disease

Pathogenicity:

the study of disease

Pathology:

body returns to its prediseased state

Period of convalescence:

signs and symptoms subside

Period of decline:

disease is most severe

Period of illness:

microfold cells (M cells) located over

Peyer's patches

Greek, meaning eat

Phago:

Protozoa

Presence of protozoa and their waste products causes symptoms

number of people who develop a disease at a specified time, regardless of when it first appeared

Prevalence:

acute infection that causes the initial illness

Primary infection:

live microbial cultures administered to exert a beneficial effect

Probiotics:

short period after incubation; early, mild symptoms

Prodromal period:

Control of Healthcare-Associated Infections

Reduce number of pathogens Infection control committees

Regulatory proteins readily break down complement proteins, minimizing host cell destruction

Regulation of complement

Portals of Exit

Respiratory Gastrointestinal tract Genitourinary tract Skin Blood

forms a protective film and lowers the pH (3-5) of skin

Sebum

occurs after the second exposure to an antigen

Secondary (memory or anamnestic) response

opportunistic infection after a primary ( predisposing ) infection

Secondary infection:

toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection

Sepsis:

also known as blood poisoning; growth of bacteria in the blood

Septicemia:

the study of reactions between antibodies and antigens

Serology:

proteins secreted by pathogens that bind iron more tightly than host cells

Siderophores

changes in a body that can be measured or observed as a result of disease

Signs:

First Line of Defense:

Skin and Mucous Membranes

Nonliving reservoirs

Soil and water

Exceptions to Koch's postulates

Some pathogens can cause several disease conditions Some pathogens cause disease only in humans Some microbes have never been cultured

Algae

Some produce a neurotoxin called saxitoxin

disease that occurs only occasionally

Sporadic disease:

the supporting connective tissue that is repaired

Stroma

intermediate between acute and chronic

Subacute disease:

no noticeable signs or symptoms (inapparent infection)

Subclinical disease:

cause an intense immune response due to release of cytokines from host cells (T cells) Cause symptoms of fever, nausea, vomiting, diarrhea, shock, and death

Superantigens

lack of resistance to a disease

Susceptibility:

is the relationship between normal microbiota and the host

Symbiosis

changes in body function that are felt by a patient as a result of disease

Symptoms:

a specific group of signs and symptoms that accompany a disease

Syndrome:

an infection throughout the body

Systemic (generalized) infection:

Attach to antigens via T-cell receptors (TCRs)

T cells

Migrate from the thymus to lymphoid tissues

T cells

Mature in the thymus

T cells combat

Antigen that requires a TH cell to produce antibodies

T-dependent antigen

Stimulate the B cell without the help of T cells Provoke a weak immune response, usually producing lgM No memory cells generatecd

T-independent antigens

produce IFN-Y, which activates macrophages, enhances complement, and stimulates antibody production that promotes phagocytosis

TH1 cells produce

cells produce IL-17 and contribute to inflammation

TH17

Tg cells produce cytokines and differentiate into

TH1cells TH2 cells TH17 cells Memory cells

activate B cells to produce lgE; activate eosinophils

TH2 cells

Serum proteins produced by the liver that assist the immune system in destroying microbes

The Complement System

Lymph, lymphatic vessels, lymphoid tissue, and red bone marrow

The Lymphatic System

Koch's Postulates 3.

The pathogen from the pure culture must cause the disease when it's inoculated into a healthy, susceptible laboratory animal.

Koch's Postulates 2.

The pathogen must be isolated from the diseased host and grown in pure culture.

Koch's Postulates 4.

The pathogen must be isolated from thee inoculated animal and must be shown to be the original organism.

Koch's Postulates 1.

The same pathogen must be present in every case of the disease

eliminates immature T cells

Thymic selection

Cannot be completed until all harmful substances are removed or neutralized

Tissue Repair

presence of toxin in the host's blood

Toxemia:

toxins in the blood

Toxemia:

ability of a microorganism to produce a toxin

Toxigenicity:

poisonous substances produced by microorganisms

Toxins

inactivated exotoxins used in vaccines

Toxoids:

found in blood and tissue fluids

Transferrin:

Iron-Binding Proteins

Transferrin: Lactoferrin: Ferritin: Hemoglobin: siderophores

may be present for days, weeks, or months

Transient microbiota

involved in the inflammation of autoimmune diseases

Tumor necrosis factor (TNF):

cleans the urethra via flow

Urine

Helminths

Use host tissue for growth Produce large masses, cause cellular damage Produce waste products Produce waste products that cause symptoms

move microorganisms out of the vaginal tract

Vaginal secretions

the number of antigen-binding sites on an antibody

Valence

viruses in the blood

Viremia:

the degree of pathogenicity

Virulence:

Transmission by an inanimate reservoir

Waterborne Foodborne Airborne

resists digestion

Waxy lipid (mycolic acid)

Animal reservoirs

Zoonoses

are diseases transmitted from animals to humans

Zoonoses

Inflammation activates ______ by the liver that cause vasodilation and increased permeability of blood vessels

acute-phase proteins

Almost all pathogens attach to host tissues in a process called

adherence (adhesion)

antigen-antibody complex Strength of the bond is the

affinity

An antigen-antibody complex forms when

antibodies bind to antigens

Protects the host by tagging foreign molecules or cells for destruction

antigen-antibody complex

High WBC counts may indicate

bacterial infections, autoimmune diseases, or side effects of medications

Microbes form

biofilms

Act in a cascade in a process called

complement activation

Overproduction of cytokines leads to a

cytokine storm

TLRs bound to PAMPs induce the release of

cytokines from the host cell that regulate the intensity and duration of immune responses

IgA proteases:

destroy IgA antibodies

Phagocytes squeeze between endothelial cells of blood vessels via

diapedesis

Antibodies interact with

epitopes, or antigenic determinants, on the antigen

Hemolysins-kill

erythrocytes by forming protein channels

Low pH (1.2-3.0) destroys most bacteria and toxins

gastric juice

Streptolysins

hemolysins produced by streptococci

Proteases modify

host cell membranes

T cells combat

intracellular pathogens

White blood cell (WBC) counts measure

leukocytes in the blood

0.02 % of serum antibodies

lgD

In blood, in lymph, and on B cells

lgD

Monomer

lgD

No well-defined function; assists in the immune response on B cells

lgD

Structure similar to lgG

lgD

0.002 % of serum antibodies

lgE

Cause the release of histamines when bound to antigen; lysis of parasitic worms

lgE

Monomer

lgE

On mast cells, on basophils, and in blood

lgE

Lymph carries microbes to lymph nodes where

lymphocytes and macrophages destroy the pathogen

The Lymphatic System .Contains

lymphocytes and phagocytic cells

Shedding and dryness of skin inhibits

microbial growth

Pathogens entering the gastrointestinal tract pass through

microfold cells (M cells)

.Some normal microbiota are

opportunistic pathogens

Toll-like receptors (TLRs) on host cells attach to

pathogen-associated molecular patterns (PAMPs)

Leukocidins-kill

phagocytic leukocytes

Capsules prevent

phagocytosis

Cytokines cause the hypothalamus to release

prostaglandins that reset the hypothalamus to a higher temperature

Trichothecene toxins inhibit

protein synthesis

Formed Elements in Blood Created in

red bone marrow stem cells via hematopoiesis

Inflammation Four signs and symptoms:

redness, swelling (edema), pain, heat

.Body constricts the blood vessels, and

shivering occurs (which raises temperature)

Bacteria produce compete with iron-binding proteins

siderophores

Koch's postulates are used to prove

the cause an infectious disease

Plasmids may carry genes for

toxins, production of antibiotics, and enzymes

Low pH (3-5) inhibit microbes

vaginal secretions

As body temperature falls (crisis),

vasodilation and sweating occurs

Low WBC counts may indicate

viral infections, pneumonia, autoimmune diseases, or cancers

The Complement System .Proteins are designated

with uppercase C and numbered in order of discovery Activated fragments are indicated with lowercase a and b


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