The Immune System and Its Diseases

Question 1

Diseases caused by pathogens are called [__] diseases.
 Transmissible diseases are [__] and can spread from one individual to another.
 Diseases that are not caused by pathogens are called [__] diseases.
 Nontransmissible diseases are not contagious and cannot be spread from one individual to another.

Answer 1

transmissible
contagious
nontransmissible

Question 2

Pathogens are [___] and viruses that can cause disease in living organisms.
 Physical contact (handshake), blood transfusion and sexual contact are modes of [__] transmission of pathogens while eating contaminated food and breathing airborne pathogens are modes of [__] transmission of pathogens.

Answer 2

microorganisms

direct - indirect

Question 3

The skin and nose hairs form a [__] barrier against pathogens in the human body, while [__], mucus and [__ __] form a chemical barrier against pathogens.

Answer 3

mechanical/physical - tears - stomach acid

Question 4

Damaged tissues at the site of infection or injury release [__] that cause the increase in the diameter and the [__] of blood vessels.
 Blood flow to the site of damaged tissue [__], causing the area to become red and warm.
 Some white blood cells leave blood [__] and move into the damaged tissue: [__] migrate to the damaged tissue, engulf pathogens and destroy them by phagocytosis.

Answer 4

chemicals - permeability
increases
capillaries - Phagocytes

Question 5

B lymphocytes are [__] once they encounter the particular antigen they bind to.
 Once activated, B cells change into [__ __] which secrete antibodies.
 These plasma cells make hundreds of thousands of identical copies of themselves.
 Plasma cells secrete a special type of molecule, called an [__], into body fluids
such as the blood and the [__].

Answer 5

activated
plasma cells
antibody - lymph

Question 6

When T lymphocytes encounter the particular antigen they bind to, they become [__] and start dividing, giving rise to clones of the activated T lymphocyte with identical receptors.
 T lymphocytes can [__] attack cells infected with the invading pathogen. They do not directly attack the [__].
 An activated T cell can also give rise to clones of [__] T cells, whose function is to protect the body against future infections by the [__ __].

Answer 6

activated
directly - pathogen
memory - same pathogen

Question 7

The [__ __] of the adaptive immune system are responsible for the secondary response.

Answer 7

memory cells

Question 8

Active immunity is the defense against a [__] by the production of [__] by the body’s own immune system following exposure to a pathogen.
 It is gained after a [__] or an exposure to a live pathogen when actual infection occurs.
 It results activation of the [] and [] lymphocytes and in the production of [__ __] that retain the ability to produce a specific antibody for many years. Therefore, it gives a long term immunity to a specific pathogen.

Answer 8

pathogen - antibodies
vaccination
B - T - memory cells

Question 9

Passive immunity is the defense against a pathogen by a transfer of antibodies from an [__] source into the body.
 It is gained after the transfer of [__] from an external source or via mother’s milk to an infant during breastfeeding.
 It does not result in production of [__ __], and therefore gives short-term immunity.
 Passive immunity provides the body with [__] protection against a pathogen, bypassing the delay that occurs while the body produces its own antibodies to the invading pathogen during the development of active immunity.

Answer 9

external
antibodies
memory cells
immediate

Question 10

The cells targeted by HIV are the [___], in particular the T cells.

Answer 10

lymphocytes

Question 11

HIV is a [__]. It infects [___] and therefore reduces the body’s abilities to make [___]. For this reason [___] diseases and cancer can develop more easily.

Answer 11

virus - lymphocytes - antibodies - infectious