ch 16 micro test 4

pathology is the study of?

disease (causes, mechanisms, and effects)

what is a disease?

a disruption in normal body function

what is a disease caused by?

infection, genetic defect, environmental stressors, etc

communicable disease

caused by a pathogen that can be transmitted from one person to another

contagious disease

type of communicable disease; spreads easily/rapidly from person to person

noncommunicable disease

not spread from person to person (often caused by genetics, lifestyle, or environment)

etiology is the study of?

finding causation/origins (of idease in medical context)

what is an infection?

invasion and multiplication of pathogen

Kolch’s postulate steps

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

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

3. The cultured pathogen must cause the same disease when introduced into a healthy, susceptible host.

4. The pathogen must then be re-isolated from the newly infected host and shown to be identical to the original organism.

what is symbiosis?

close relationship between two organisms

what is commensalism

type of symbiosis where one organism benefits and other is neither helped or harmed

what is mutualism

type of symbiosis when both organisms benefit

what is parasitism

type of symbiosis where one organism benefits and other is harmed

what is transient flora

microbes that temporarily live on or in the body

example of transient flora

the skin

what is microbial antagonism

when normal microbiota inhibit growth of harmful microbes (through completion)

what is a primary infection

intitial infection cause by a pathogen

what is a secondary infection

infection that occurs during or after a primary infection (due to already weakened immune system)

what is an inapparent/subclinical infection

infection that produces no noticeable symptoms; pathogen still present and potentially transmissible

what is immunocomprised by congenital

present at birth

what is immunocompromised by acquired

from illness like HIV/AIDS, cancer, or diabetes

what is immunocompromised by induced

from treatments like chemotherapy, immunosuppressive drugs, radiation

what is incubation

time between initial infection and the appearance of the signs or symptoms

what is prodromal period

early stage of illness - mild symptoms appear (fatigue, aches)

what is period of illness

stage when symptoms are most severe (peak disease)

what is period of decline

phase when symptoms begin to subside - patient starts to recover- vulnerable to secondary infections

what is convalescence

final stage of recovery - return to normal function and strength

hygiene hypothesis

early exposure to microbes is essential for developing a balanced immune system

example of hygiene hypothesis

when children grow up in overly clean environments, their immune systems may not learn to tolerate harmless substances → increases risk or allergies, asthma, and autoimmune disease

what is a cytokine storm

dangerous immune overreaction where body releases too many pro-inflammatiry cytokines in a short period of time

what is cause of cytokine storm

can be result of infection, autoimmune disease, cancer therapies, or transplant communications

consequences of cytokine storm

• fever, fatigue, and rash

• organ failure and shock

• high motrality risk if untreated

what is cross reactive antibodies

antibodies that bind to more than one antigen due to structural similarity between those antigens

what is a rheumatic fever

triggered by poorly treated strep throat (Group A Streptococcus) add to from slide 30!!!

what is virulence

the strength of a microbe to cause a disease

what is an injectisome

needle-like protein structure used by certain Gram-negative bacteria to inject toxins or effector proteins directly into host cells

what is C5a

an inflammatory molecule produced by the complement system to recruits phagocytes to site of infection

what is a C5a peptidase

an enzyme produced by certain pathogenic bacteria which inactivates C5a → helps them evade the immune system

what is M protein

surface virulence factor that helps bacteria avoid the host immune system by 3 ways

how does M protein avoid the host immune system?

1. blocking complement proteins

2. binding host proteins → bacterium now appears like part of the host

3. being highly variable → makes developing vaccines difficult

what is capsules

thick, gelatinous layer that surrounds the cell wall of some bacteria

what do capsules prevent?

prevents phagocytosis and helps to adhere to host tissue

what do cell wall proteins and waxes do?

aid attachment and protect from phagocytosis + resist drying out and disinfectants

what are leukocidins

toxins that destroy WBCs

what are hemolysins

enzymes/toxins that destroy cells by lysing their cell membranes

what are coagulases

enzymes produced by certain bacteria that cause blood plasma to clot

what is the function of kinases

break down clots → allows bacteria to escape and spread through tissues

what is the purpose of hyaluronic acid and collagen

they are connective tissue components

what is the function of hyaluronidase and collagenase

breaks down hyaluronic acid and collagen → bacteria spreads deeper into host tissue

what are necrotizing factors

toxins or enzymes which destory host tissue cells (causing necrosis)

why does necrotizing factors have an easier invasion?

because of the necrosis, there is less of a tissue barrier

what are hypothermic factors

microbial products that reduce host’s body temperature

how can hypothermic factors occur

can occur in severe infections or septic shock

what is function of DNase and Streptodornase

breaks down DNA in pus (liquifying it) so that bacteria can spread more easily

streptodornase is DNase specifically produced by what?

streptococcus bacteria

what are proteases

enzymes that break down proteins

example of proteases

structural proteins like collagen (microbe penetrates tissues more easily)

destroying antibodies

what is adherence

ability of microbe to attach to a host surface

what are adhesios/ligands

protein molecules that bind to objects and help them attach

what are cytotoxins

toxins that damage or kill host cells by disrupting vital cellular functions

diphtheria toxin is an example of what

a cytotoxin

what is diphtheria toxin produced by

corynebacterium diptheriae

cytotoxin which inhibits protein synthesis (in eukaryotes) →

leads to cell death

what are neurotoxins

toxins that specifically target the nervous system

what do neurotoxins affect

nerve cells’ (neurons) ability to send signals

what produces botulinum toxin

clostridium botulinum

what is the most potent neurotoxins to humans

botulinum toxin

steps of botulinum toxin

toxin blocks nerve signals → leads to muscle weakness → progresses to paralysis → and in extreme cases, respiratory failure and death

tetanus toxin is produced by?

clostridium tetani

tetanus toxin is found where

soil, dust, and animal feces

neurotoxin causes spastic (rigid) paralysis which is…

sustained, uncontrolled contractions

symptoms of spastic (rigid) paralysis

muscle stiffness + spasms → lockjaw → arching of back → difficulty swalling or breathing

if spastic rigid paralysis is left untreated?

it can be fatal

what are enterotoxins

toxins that specifically affect the intestines

what do enterotoxins disrupt

normal fluid balance

enteroxins disruption leads to

diarrhea, vomiting, abdominal cramps

an example of an enterotoxin is

choleragen toxin

choleragen toxin is produced by

vibrio cholerae (causes cholera)

where/what is choleragen toxin specific to?

the intestinal lining

symptoms of choleragen toxin

massive, watery diarrhea → severe dehydration

what can untreated choleragenn toxin result in

shock and death

erythrogenic toxin is produced by

strains of streptococcus pyogens

example of erythrogenic toxin

scarlet fever

erythrogenic toxin does what

stimulates massive immune response → damages blood vessels → characteristic red rash

what is staphylococcal exfoliatins

targets proteins in outer layer of skin - causes skin to peel

what are exotoxins

proteins secreted (outside the cell) by bacteria during growth

what are endotoxins

componenents within the cell membrane of G- bacteria: released upon cell death (membrane breakdown)