SIUE BIO 250 - Exam 4/ Final

symptoms

subjective characteristics of disease felt by th epatient

signs

objective manifestation s of disease observed or measured by others

syndrome

group of symptoms and signs that characterize a disease or abnormal condition

asymptomatic or sublinical

infections lack symptoms but still may have signs of infection

etiology

study of the cause of disease

kochs postulates

a sequence of experimental steps for directly relating a specific microbe to a specific disease

1st Koch's Postulate

the suspected agent (bacterium, virus, etc.) must be present in every case of disease

2nd Koch's Postulate

That agent must be isolated and grown in pure culture

3rd Koch's Postulate

the cultured agent must cause the disease when it is inoculated into a healthy susceptible experimental host

4th Koch's Postulate

The same agent should be found in the diseased experimental host

Exceptions to Koch's Postulates

some pathogens can't be cultured in the laboratory

diseases cause by a combination of pathogens and other cofactors

ethical concerns when applying to humans

pathogenicity

ability of a microorganism to cause disease

virulence

degree of pathogenicity/ability to produce disease)

extracellular enzymes

-Secreted by the pathogen

-Dissolve structural chemicals in the body

-Help pathogen maintain infection, invade, and avoid body defenses

Toxins

chemicals that harm tissues or trigger host immune responses that cause damage

Exotoxins

toxic substances that bacteria secrete into their environment

Endotoxins

released only when bacteria die and their cell walls break down

Antiphagocytic factors

factors that prevent phagocytosis by the hosts phagocytic cell

antiphagocytic factors - bacterial capsule

composed of chemicals not recognized as foreign in immune system

stages of infections disease (in order)

incubation period

prodromal period

illness

decline

convalescence

what is the incubation period

the period between exposure to an infection and the appearance of the first symptoms

what is the prodromal period

short period after incubation; early, mild symptoms

what is the illness period

most severe, sings/symptoms. typically sees doctor

what is the decline period

declining signs and symptoms

what is the convalescence period

patient/tissue completely repaired. no signs or symptoms

portals of exit

pathogens must leave host through portals of exit

types of portals of exit

contact

vehicle

vector

types of contact transmission

direct, indirect, droplet

direct contact transmission

person to person transmission

indirect contact transmission

pathogens are spread from host to host by formites

droplet contact transmission

spreading of pathogens in droplets of mucus (exhaling, couching, sneezing)

types of vehicle transmission

airborne

waterborne

foodborne

bodily fluid

airborne tranmission

pathogens travel more than 1 m via an aerosol.

can occur from sneezing, couching, AC systems, sweeping

waterborne transmission

spread by gastrointestinal. fecal -oral infection (clean water)

foodborne transmission

pathogens spread in and on food. inadequately processed, cooked, or refrigerated foods

bodily fluid transmission

when blood, urine, salvia comes in contact with skin/mucous membranes

types of vector transmission

biological and mechanical

biological transmission

pathogen reproduces in the vector; transmitted via bites or feces (arthropods)

mechanical vetors

passive transmit pathogens present on their body to new hosts

diseases can be classified in a number of ways

-taxonomic categories

-the body system they affect

-their longevity and severity

-how they spread to their host

-the effects they have on populations

acute disease

disease in which symptoms develop rapidly and that runs in course quickly

chronic disease

disease with usually mild symptoms that develop slowly and last a long time

subacute disease

disease whose time course and symptoms range between acute and chronic

asymptomatic disease

disease without symptoms

latent disease

disease that appears a long time after infection

communicable disease

disease transmitted form one host to another

contagious disease

communicable disease that is easily spread

noncommunicable disease

disease not passed from person to person

local infection

infection confined to a small region of the body

systemic infection

widespread infection in many systems of the body; often travels in the blood/lymph

focal infection

infection site that serves as a source of pathogens for infections at other sites in the body

primary infection

initial infection within a given patient

secondary infection

infections that follow a primary infection; often by opportunistic pathogens

incidence

number of new cases of a disease in a given area during a given period of time

prevalence

number of total cases of a disease in a given area during a given period of time

descriptive epidemiology

careful tabulation of data concerning a disease

analytical epidemiology

retrospective look to determine probable cause/mode of transmission/method of prevention of a specific disease

experimental epidemiology

tests a hypothesis concerning the cause of a disease (application of koch's postulates)

Healthcare-associated (nosocomial) infections (HAI)

infections gotten from being in a hospital (a pathogen HQ)

exogenous HAI

from microorganisms outside the individual

endogenous HAI

when patient's normal microbiota becomes altered

iatrogenic HAI

results from modern medical procedures

superinfections HAI

use of antimicrobial drugs inhibits some resident microbiota allowing other microbes to thrive

species reistance

the immune resistance of a particular species to various pathogens, parasites, or harmful agents

the first line of defence

composed chiefly of external physical barriers and associated chemicals and processes

the second line of defense

internal and composed of protective cells, bloodborne chemicals and processes that inactive or kill invades

together the first two lines of defense are called...

innate immunity

the third line of defense is called

adaptive immunity

skin is composed of two layers

epidermis and dermis

epidermis

multiple layers of tightly packed cells.

epidermal dendric cells phagocytize pathogens

dermis

collagen fibers help skin resist abrasions that could include microorganism

what is perspiration

sweat

perspiration contains

antimicrobial peptides and lysozymes

antimicrobial peptides

act against microorganisms

lysozyme

destroys cell wall of bacteria

what does sebum do

keeps hair and skin soft and waterproof

lower skin pH to inhibit bacteria

layers of mucous membrane

epithelium and deeper connective tissue

epithelium in the mucous membrane

-thin outer covering of mucous membranes

-tightly packed to prevent entry of many pathogens

-continual shedding of cells carriers away microorganisms

-goblet and ciliated columnar cells help remove invaders

skin: number of cell layers

many

mucous membrane: number of cell layers

one to a few

skin: cells tightly packed

yes

mucous membrane: cells tightly packed

yes

skin: cells dead or alive

outer: dead

inner: alive

mucous membrane: cells dead or alive

alive

skin: mucous present

no

mucous membrane: mucous present

yes

skin: relative water content

yes

mucous membrane: relative water content

yes

skin: lysozyme present

yes

mucous membrane: lysozyme present

with some

skin: sebum present

yes

mucous membrane: sebum present

no

skin: cilia present

no

mucous membrane: cilia present

yes, trachea, uterine tubes

skin: constant shedding and replacement of cells

yes

mucous membrane: constant shedding and replacement of cells

yes

lacrimal apparatus

-produces and drains tears

-blinking spreads tears and washes surface of eye

-lysozyme in tears destroys bacteria

microbial antagonism

microbiome competes with potential pathogens

function of saliva

washes microbes from teeth, gums, tongue. contains lysozyme

function of stomach acid

digests and/or inhibits microorganisms