chapter 16 host microbe interactions

Question 1

what is a pathogen

Answer 1

Pathogens are disease-causing microbes that cause noticeable damage to the host in order to survive and also are parasites

Protozoa and helminths are parasites

Question 2

define the normal microbiota

Answer 2

It is a group of organisms that colonize the body’s surfaces but do not usually cause diseases.

Located on your body exterior surfaces such as your skin gi tract urinary/ genitalia and lungs

Question 3

define an infection

Answer 3

it is colonization by a pathogen on or within the body

Question 4

define an infectious dose

Answer 4

Number of microbes sufficient to establish an infection

Question 5

what is an infectious disease

Answer 5

An infection that prevents the body from functioning normally.

Question 6

how are diseases charaterized

Answer 6

Diseases are characterized by symptoms and signs

symptoms
Subjective effects of a disease experienced by the patient, such as pain and nausea and a fever

signs
Effects of a disease observed by examining the patient and objective

You cna have a disease without being caused by a pathogen

Question 7

explain the difference between primary and opportunistic pathogens

Answer 7

a primary pathogen is a pathogen that is a microorganism or virus that causes diseases in otherwise healthy indivisuals
Malaria, strep throat,influenza, and tuberculosis are primary pathogens

Opportunistic pathogen causes diseases when the body’s innate or adaptive defenses are compromised or when introduced into an unsual location

Question 8

virulence vs virulence factors

Answer 8

virulence -Relative ability of a pathogen to overcome body defenses and cause disease.

virulence factors are traits of a microbe that promote pathogenicity such as adhesins toxins or digestive enzymes

Question 9

what is an incubation period

Answer 9

Interval between entrance of a pathogen into a susceptible host and the onset of illness caused by that pathogen

Question 10

define interferons

Answer 10

interferons are apart of the second line of defense and limit viral spread in a host by causing cells that produce enzymes when activated induce affected cells to undergo aptosis.

Question 11

describe the microbes fungi

Answer 11

Fungi in the normal microbiota like yeast can cause disease in immunocompromised hosts

Cell wall made of chitin
Yeast infections
Fungi referred to as dermatophytes can cause superficial infections in the hair skin and nails

Dermophyctes cause disease such as ringworm and athlete’s foot

Question 12

define protozoa and helminths

Answer 12

they are eukaryptic unicellular parasites and they attach to host cells via specific receptors

Type of protozoan disease is Plasmodium falciparum and malaria

A type of helminth is a tapeworm that causes diseases in humans, flatworms, and nematodes, amd pinworms

Question 13

define a virus

Answer 13

A virus is a type of pathogen, and they are not considered life forms because they need a host to replicate and to keep the host from destroying the infected self

Viruses do not have a metabolism and they do not have both types of nucleic acids; they either have RNA or DNA.
Viruses are acellular and viral populations evolve as life forms evolve

damage to the host can occur as a direct result of an infection

Question 14

describe the adaptive (specific) defenses immunity

Passive immunity

Answer 14

Natural passive immunity is immunity that results when antibodies from a woman are transferred to her developing fetus such as an infant during breastfeeding

artificial passive immunity results when antibodies contained in the serum of the animals are injected into an individual

Question 15

define active immunity

Answer 15

Natural active immunity is immunity that results from an immune response in an individual after exposure to an infectious agent

Artificial active immunity is an immunity that results from an immune response in an individual after vaccinations

Question 16

active immunity verus passive immunity

Answer 16

immunity is immunity that results when antibodies are transferred to an individual

passive immunity is immunity that results from an immune response in an individual upon exposure to an antigen

Question 17

describe B lymphocytes and T lymphocytes

Answer 17

T lymphocytes are invovled in eliminatig the antigen by destroying infected cells and help assist other parts of the adaptive immune response

B lymphocytes produce Y shaped proteins called antibodies that bind to specific antigens and mark them as an invader to be eliminated

Question 18

describe the first line of defense

Answer 18

The first line of defense is a surface protection composed of genetic componets, chemical and physiological barriers such as the skin and the mucous membrane that keep microbes that keep microbes from penetrating sterile body compartments such as the body’s tissues

Question 19

describe the complement system

Answer 19

the complement system is apart of the first line of defense and is a series of proteins in blood that can be activated to help destroy and remove invading microbes and promote inflammation

Question 20

describe phagocytosis

Answer 20

Phagocytosis is a second line of defense when a phagocyte engulfs microbial invaders

Question 21

define an inflammatory response

Answer 21

This is a second line of defense that coordinates innate response to contain a site of damage, localizing the response, eliminating the invader, and restoring tissue function.

Question 22

describe a fever

Answer 22

A fever is an innate response and an innate defense and it interferes with the growth of some pathogens and causes a higher than normal body temperature

Question 23

define inflammation

Answer 23

Set of signs and symptoms (swelling, heat, redness, and pain) that characterizes an innate immune response to infection or injury and is an innate defense

Question 25

Nonspecific white blood cells

Answer 25

A nonspecific white blood cells are neutrophils major type of phagocytic cell are microbe destroying machines that help destroy invading pathogens and microbial invaders as part of the phagocytic process. , lymphocytes are involved in adaptive immunity such as B and T cells. monocytes which eventually become macrophages Type of phagocytic cell that resides in tissues and has multiple roles, including scavenging debris and producing pro-inflammatory cytokines, eosinophils are involved in fighting off allergic reactions, and basophils contain histamine that help induce an inflammation response .

Question 26

what is the difference between localized and systematic infections

Answer 26

Localized infections the infection is limited to one site or in the body. An example is a boil caused by Staphylococcus aureus.

Systemic infections Infection in which the infectious agent spreads throughout the body. An example is lyme disease and measles

Question 27

what is the difference between acute, chronic, and latent infections

Answer 27

Acute infection is an infection characterized by symptoms that develop fairly quickly and last a relatively short time.An example of an acute infection is strep throat AND pneumonia

Chronic infection is an infection that generally develops slowly and lasts for months or years. An example is tuberculosis and leprosy

Latent infection is an infection in which the infectious agent is present but not causing symptoms. Latent infections are never completely eliminated; the microbes continue to exist in the host tissues, held in check by the immune system without causing any symptoms latent tuberculosis

Question 28

define symbiosis

Answer 28

Symbiosis is the living together of two dissimilar organisms or symbionts

Question 29

define mutulaism

Answer 29

Mutualism is when a symbiotic association in which both partners benefit.

For example some bacteria in the large intestine synthesize vitamin K that are then available for our body to asorb

Question 30

define commensalism

Answer 30

Commensalism is a Relationship between two organisms in which one partner benefits and the other is unaffected. Example many microbes living on the skin are neither harmful or helpful to the host but they obtain food from the host

Question 31

define parasitism

Answer 31

Parasitism is an association when one organism benefits the parasite at the expense of the other. All pathogens are parasites

Question 32

what is the difference between hypersensitivity and immunodeficiency

Answer 32

Immunodeficiency is when the immune system does not provide an adequate response leaving a person vulnerable to an infection

Hypersensitivity is an exaggerated immune response that damages tissues

Question 33

what is the typical course of an infectious disease from a host perspective

Answer 33

incubation period
prodromal phase
period of illness
convalescence period

Question 34

define the incubation period

Answer 34

Incubation Period is the interval between the entrance of a pathogen into susceptible host and the onset of of illness caused by that pathogen

Question 35

define the prodromal phase

Answer 35

Prodrome is the period of early, vague symptoms indicating the onset of a disease

Question 36

define the period of illness

Answer 36

Period of illness is the period of time in which symptoms and signs of disease can occur .

Question 37

define the convalescence phase

Answer 37

convalescence is the period of recuperation and recovery from an illness

Question 38

what are carriers (asymptomatic)

Answer 38

hosts that harbor and spread infectious agent for long periods of time in absence of signs or symptoms

Question 39

what are the virulence factors do pathogens have to aid in colonization ?

Answer 39

MAC binding protiens
C5a peptidase
IgA proteases

Question 40

what does C5a peptidase do

Answer 40

C5a Peptidases this an enzyme that degrades the complement system, component C5a a chemoattractant that recruits phagocytic cells

Question 41

what is the hygiene hypothesis

Answer 41

The hygeine hypothesis is the proposal that insufficient exposure to microbes during childhood can lead to allergies and autoimmune diseases

Question 42

what is a secondary infection

Answer 42

an infection that occurs along with or immediately following another infection, usually as a result of the primary infection

Question 43

what are superinfections

Answer 43

Superinfections caused by a treatment of some kind for an infectious disease. An example is a yeast infection

Question 44

what are subclinical asymptomatic infections

Answer 44

Subclinical ( asymptomatic) infections is an infection by a pathogen that causes few or no symptoms of infection in the host

Question 45

what is alloimmunity

Answer 45

alloimmunity is damaging reaction of the immune system against self antigens

Question 46

what is autoimminity

Answer 46

When the immune system attacks its own healthy cells. It can’t distinguish between self vs non-sel