Ch 15 Host Microbe Relationships

Question 1

immunity

Answer 1

exposure to disease agent at another time may protect from contracting the disease later

Question 2

pathogen

Answer 2

parasite capable of causing disease to the host

Question 3

symbiosis

Answer 3

host harbors another organism, living together, includes mutualism, commensalism, and parasitism

Question 4

mutualism

Answer 4

*both members live together & benefit from the relationship

Question 5

parasitism

Answer 5

parasite benefits and host is harmed

Question 6

commensalism

Answer 6

two species live together and one benefits but the other neither benefits nor is harmed

Question 7

kinds of disease

Answer 7

communicable, non-communicable

Question 8

communicable disease

Answer 8

*infectious disease that can be spread from one host to another.
*contagious diseases

Question 9

noncommunicable disease

Answer 9

*infectious diseases that are not spread from one host to another
*non contagious diseases
1) infection from normal microflora
2) ingestion of performed toxins (e.g. food poisoning)
3) infection caused by certain organisms found in environment

Question 10

disease process

Answer 10

*actions microbes take like gaining access to the host, adhering to and colonizing cell surfaces, invade tissue, produce toxins & other metabolic products.

Question 11

how bacteria cause a disease

Answer 11

*bacteria have special structures or physiological characteristics that improve chances of infection called virulence factors
*bacteria enter body by penetrating skin or mucous membranes, by sexual transmission, by ingestion or inhaled, by transmission on fomite.
*attach or adhere to cell surfaces, then colonize the cells surfaces or penetrate it. (degree of invasiveness) is its ability to invade and grow in host tissue.

Question 12

virulence factor

Answer 12

*structural or physical characteristics that help organisms cause infection and disease.
*pili- cell and tissue adhesion- difficult for phagocytes to engulf bacteria that have capsules or attachment pili.
*enzymes- help evade hosts defenses or protect organism from the host
*toxins- can directly cause disease

Question 13

hyaluronidase

Answer 13

enzyme that digests hyaluronic acid, the glue like substance that holds cells of certain tissue together.

Question 14

coagulase

Answer 14

*enzyme that accelerates the coagulation (clotting) of blood
*can prevent the bodies immune defenses from getting to bacteria.

Question 15

streptokinase

Answer 15

*enzyme that dissolves blood clots
*

Question 16

bacterial toxins

Answer 16

*substance that is poisonous to other organisms
*exotoxins
*endotoxins

Question 17

exotoxins

Answer 17

*soluble substances secreted in host tissues
*more powerful toxins produced by several gram-positive and a few gram-negative
*some exotoxins target or are attracted to particular tissues (neurotoxins)

Question 18

endotoxins

Answer 18

*part of cell wall and are released into host tissue
*usually gram negative bacteria, released when bacteria dies or divides

Question 19

toxemia

Answer 19

*the spread of exotoxins by blood from the site of infection

Question 20

toxoid

Answer 20

altered toxin that has lost its ability to cause harm but retains antigenicity