Exam 3 Review: Pathology, Infection, and Disease

A collection of flashcards focusing on key terms and definitions related to pathology, infection, and disease as covered in the exam review.

Pathology

The study of disease.

Etiology

The cause of a disease.

Pathogenesis

The manner in which a disease develops.

Infection

Invasion or colonization of the body by pathogens.

Infectious disease

Occurs when an infection results in any change in the state of health.

Symbiosis

A relationship between organisms in which at least one organism is dependent on the other.

Commensalism

One organism benefits, and the other is unaffected.

Mutualism

Both organisms benefit.

Parasitism

One organism benefits at the expense of the other.

Koch’s Postulates

• A series of principles used to establish the cause of infectious disease.

• same pathogen use be present in every case of disease

• pathogen must be isolated from diseased host and grown in pure culture

• pathogen from pure culture must cause the disease when inoculated into a healthy lab animal

• pathogen must be isolated from the inoculated animal and proven to cause the disease

Koch’s Postulates exceptions

• some pathogens can cause several disease conditions

• some pathogens cause disease only in humans

• some microbes have never been cultured

• different pathogens may cause same symptoms

Symptoms

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

Signs

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

Syndrome

a specific group of signs and symptoms that accompany a disease

Communicable disease

A disease that is spread from one host to another.

• covid

• chicken pox

• measles

• genital herpes

• influenza

• tuberculosis

Contagious diseases

Diseases that are easily and rapidly spread from one host to another.

Noncommunicable disease

a disease that is not spread from one host to another

• tetanus

Sporadic disease

Disease that occurs only occasionally.

Endemic disease

Disease constantly present in a population.

Epidemic disease

Disease acquired by many people in a given area in a short time.

Pandemic disease

Worldwide epidemic.

Local infection

Pathogens are limited to a small area of the body.

Systemic infection

An infection spread throughout the body by the blood and lymph.

Focal infection

systemic infection that began as a local infection

Sepsis

Toxic inflammatory condition arising from the spread of microbes.

Bacteremia

Bacteria in the blood.

Septicemia

growth of bacteria in the blood, blood poisoning

Toxemia

toxins in the blood

Viremia

Viruses in the blood.

Primary infection

acute infection that causes initial illness

Secondary infection

opportunistic infection after a primary infection

Subclinical infection

no noticeable signs or symptoms

Incubation period

Interval between initial infection and first signs and symptoms.

Prodromal period

Short period after incubation with early, mild nonspecific symptoms.

Period of illness

When the disease is most severe.

Period of decline

When signs and symptoms subside.

Period of convalescence

When the body returns to its prediseased state.

Direct contact transmission

Requires close association between the infected and a susceptible host.

Congenital transmission

transmission from mother to fetus or newborn at birth

Indirect Contact Transmission

already to host by nonliving object

Droplet Transmission

transmission through airborne droplets less than 1 meter

Vector

An organism that transmits infectious diseases.

• anthropods

• fleas

• ticks

• mosquitoes

Mechanical transmission

anthropod carried pathogen on its feet

Biological Transmission

pathogen reproduces in the vector from bites or feces

fomite

Healthcare-Associated Infections (HAIs)

Infections acquired while receiving treatment in a health care facility.

• affects 1 in 31 patients in the US

Compromised host

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

Emerging Infectious Diseases

Diseases that are new or changing, increasing in incidence, or showing potential to increase.

Emerging infectious disease contributing factors

• genetic recombination

• evolution of existing organisms

• widespread use of antibiotics and pesticides

• inherent genetic instability

• change in weather

• war and disaster

• animal control

• public health failure

Mucous membranes

• respiratory tract

• digestive canal

• genital system

• urinalysis system

• conjunctiva

most commonly used portal of entry

respiratory tract

Pathogenicity

The ability to cause disease.

Virulence

The degree of pathogenicity.

Parenteral route

microorganisms directly deposited into tissues beneath the skin or into mucous membranes

• punctures

• injections

• bites

• cuts

• wounds

• surgery

infectious dose for 50% of a sample population

measures virulence of a microbe

lethal dose for 50% of a sample population

measures potency of a toxin

Coagulases (enzyme)

coagulate fibrinogen forming fibrin

Kinases (enzyme)

digest fibrin clots

hyaluronidase (enzyme)

digests hyaluronic acid, hold cells together

collagenase (enzyme)

breaks down collagen

IgA proteases (enzyme)

destroy IgA antibodies

siderophores

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

exotoxins

proteins produced and secreted by bacteria

• soluable in bodily fluids and destroy host cells

• some highly lethal

antitoxins

antibodies against specific exotoxins that provide immunity

toxoids

inactivated exotoxins used in vaccines

A-B toxins

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

• diphtheria toxin

gentoxins

damage DNA

• causes mutations

• disrupts cell division

• lead to cancer

membrane disrupting toxins

lyse host cells by disrupting plasma membranes

leukocidins

kill phagocytic leukocytes

hemolysins

kill erythrocytes by forming protein channels

streptolysins

hemolysins produced by streptococci

superantigens

cause an intense immune response due to release of cytokines from host cells (T cells)

• cause fever , nausea, vomiting, diarrhea, shock, and death

endotoxins

released during bacterial multiplication when gr negative bacteria die

• tumor necrosis factor

• weaken blood brain barrier

pathogenicity

the ability to cause disease

virulence

the degree of pathogenicity

Phagocytosis

The ingestion of a microorganism or other substance by a cell.

Antigen

Substances that cause the production of antibodies.

IgG

An antibody that crosses the placenta and protects the fetus.

IgA

An antibody that is common in mucous membranes, saliva, tears, and breast milk.

Cellular Immunity

A response involving T cells combatting intracellular pathogens.