Chapter 10

Question 1

Describe a pathogen

Answer 1

a disease-causing organism

Question 2

Describe a transmissible disease

Answer 2

a disease in which the pathogen can be passed from one host to another

Question 3

Describe transmission of pathogens

Answer 3

direct contact: through blood and other body fluids
indirect: contaminated surfaces, food, animals and air

Question 4

Describe the body defenses

Answer 4

skin, hairs in the nose, mucus, stomach acid and white
blood cells

Question 5

Describe active immunity

Answer 5

defence against a pathogen by antibody production in the body

Question 6

Describe antibodies

Answer 6

proteins produced by lymphocytes that bind to antigens leading to direct destruction of pathogens or marking of pathogens for destruction by phagocytes, there shape needs to be complimentary to the shape of the antigens for them to bind

Question 7

Explain active immunity

Answer 7

Some of the lymphocytes that produced the specific antibodies, as a result of infection by a pathogen, remain in the lymph nodes as memory cells for some time, and can divide rapidly to produce more antibodies to respond to further infections by the same pathogen. This creates immunity to the disease caused by the antigen.

Question 8

Describe how active immunity can be gained via vaccination

Answer 8

Vaccination: weakened form of the pathogen that has antigens, or antigens from the pathogen

The presence of the antigens triggers an immune response:
lymphocytes make specific antibodies to combat possible infection some remain in the lymph nodes as memory cells that can reproduce quickly and produce antibodies in response to any subsequent invasion of the body by the same pathogen providing long-term immunity.

Question 9

Explain the role of vaccination in controlling the
spread of diseases

Answer 9

reduces transmission – herd immunity, which helps prevent disease outbreaks

Question 10

Explain passive immunity

Answer 10

short-term (no formation of memory cells) defence against a pathogen by antibodies acquired from another individual, including across the placenta and in breast milk (antibodies provide the baby with protection against infection at a time when the baby’s immune responses are not yet fully developed)

Question 11

Describe and explain cholera

Answer 11

a disease caused by a bacterium which is transmitted in contaminated water : cholera bacterium produces a
toxin that causes secretion of chloride ions into the s.i. causing osmotic movement of water into the gut, causing diarrhoea, dehydration & loss of ions from the blood

Question 12

check 10.1.5