6.2.3 - Non-Specific Immune Responses

Question 1

What Triggers An Immune Response?

Answer 1

Foreign antigens.

Question 2

What Are Antigens?
(2 Points)

Answer 2

~ Are molecules such as proteins or glycoproteins, located on the surface of cells.

~ They recognise other antigens on cell surfaces as being self or non-self, triggering the relevant immune response.

Question 3

What Are The 2 Types Of Immune Responses?

Answer 3

~ Non-specific.

~ Specific.

Question 4

What Is The Non-Specific Immune Response?
(3 Points)

Answer 4

~ Happens in the same way for all microorganisms, regardless of the foreign antigen they have.

~ It is not antigen-specific.

~ Attack on microorganisms happens immediately.

Question 5

What Mechanisms Does The Non-Specific Immune Response Include?
(3 Points)

Answer 5

~ Inflammation.

~ Production of interferons.

~ Phagocytosis.

Question 6

What Is Inflammation?

Answer 6

Where the site of pathogen entry (Infection) becomes red, warm, swollen and painful.

Question 7

What Cells Release Histamine?

Answer 7

Mast cells.

Question 8

What Is Histamine?

Answer 8

Chemical signalling molecule, enables cell signalling.

Question 9

What Is Vasodilation?

Answer 9

Widening of blood vessels.

Question 10

Describe The Process Of Inflammation
(5 Points)

Answer 10

~ Mast cells secrete histamine in response to tissue damage.

~ Histamine causes vasodilation around the infection site, increasing blood flow through the capillaries.

~ Capillary walls become permeable (Leaky) allowing fluid to enter the tissues creating swelling and also plasma to leave the blood.

~ Phagocytes leave the blood and enter the tissue, engulfing foreign particles.

~ Cytokines are released triggering an immune response in the infected area.

Question 11

What Are Interferons?

Answer 11

Anti-viral proteins.

Question 12

How Are Interferons Produced?

Answer 12

By cells infected by viruses.

Question 13

What Do Interferons Do?

Answer 13

Prevent viruses from spreading to uninfected cells.

Question 14

How Do Interferons Prevent Viruses From Spreading To Infected Cells?
(3 Points)

Answer 14

~ Prevent viral replication by inhibiting the production of viral proteins.

~ Activate cells involved in the specific immune response (E.g. WBC), to eliminate infected cells.

~ Activate other mechanisms of the non-specific immune response. E.g. By promoting inflammation.

Question 15

What Are Phagocytes (Macrophage)?
(4 Points)

Answer 15

~ Type of WBC that is responsible for removing dead cells and invasive microorganisms, by engulfing and digesting.

~ Found in the blood and tissues, can leave the cell by squeezing through capillary walls.

~ They are the first cells to respond to pathogen inside the body, released in large numbers in response to infection.

~ Carry out the process of phagocytosis.

Question 16

What Is Phagocytosis?

Answer 16

Process of engulfing and digesting pathogens.

Question 17

Describe The Process Of Phagocytosis
(6 Points)

Answer 17

~ Phagocytes are attracted to chemicals released by pathogens and body cells which are under attack.

~ Attracting the phagocyte to the location of the pathogen, they recognise it as being non-self.

~ Cell surface membrane of the phagocyte extends out and around the pathogen, engulfing and trapping it in a phagocytic vacuole.

~ Lysosomes fuse with the phagocytic vacuole, releasing digestive enzymes (Including lysozyme) which digest the pathogen.

~ After digestion, the phagocyte presents the pathogens antigens on its own cell surface.

~ Become an antigen presenting cell, initiating the specific immune response.