Lab 2 immune system

Question 1

Describe the role and function of neutrophils.

Answer 1

Neutrophils are the first white blood cells recruited to sites of acute inflammation, in response to chemotactic signals. Neutrophils represent the first line of defence in response to invading microbes, by phagocytosis of pathogens

Question 2

Describe the role and function of monocytes?

Answer 2

Monocytes are phagocytes that circulate in the blood. When monocytes migrate into tissues,they develop into macrophages. They are powerful phagocytes. (Can stimulate other immune cells by presenting foreign antigen). They can send out powerful chemical signals called monokines.

Question 3

Describe the role and function of mast cells?

Answer 3

They mediate inflammatory responses. They store a number of different chemical mediators - histamine, interleukins,proteoglycans ad enzymes)- these are present in coarse granules. Upon stimulation by an allergen. the mast cells release the contents of their granules (degranulation) into surrounding tissues and produce a local response.

Question 4

Describe the role and function of eosinophils?

Answer 4

Eosinophilic functions include: movement to inflamed areas, trapping substances, killing cells, anti-parasitic and bactericidal activity, participating in immediate allergic reactions, and modulating inflammatory responses through degranulation.

Question 5

Describe the role and function of basophils?

Answer 5

In addition to fighting parasitic infections, basophils play a role in: Preventing blood clotting: Basophils contain heparin. This is a naturally occurring blood-thinning substance. Mediating allergic reactions: In allergic reactions, the immune system is exposed to an allergen. Basophils release histamine during allergic reactions. Basophils are also thought to play a role in causing the body to produce the antibody called immunoglobulin E (IgE).

Question 6

What are the following labels?

Answer 6

1-antigen binding region

2-light chain

3-heavy chain

4-Fc region

5-Fab region

Question 7

Describe the role and fucntion of natural killer cells.

Answer 7

Natural killer (NK) cells are a type
of lethal white cell/lymphocyte. NK cells are armed with
granules filled with potent chemicals e.g. perforin.
(while killer T cells look for antigen
fragments bound to self-MHC molecules),
NK cells recognize cells lacking self-MHC
molecules. Thus NK cells have the
potential to attack many types of
foreign cells including virally infected and tumour cells.

Question 8

What are lymphocytes and where are they produced?

Answer 8

Small white blood cells produced in the lymphoid organs. (paramount in immune defences).

Question 9

What are the key properties and function of bone marrow?

Answer 9

Bone marrow, the soft tissue in the hollow
center of bones, is the ultimate source of
all blood cells, including white blood cells
destined to become immune cells.

Question 10

What is the function of the thymus?

Answer 10

It’s primary function is to promote the development of cells of the immune system called T lymphocytes.

Question 11

What is the function of the lymph nodes?

Answer 11

Lymph nodes play two major roles in the body: filtration of lymph and production of immune responses.

Lymph nodes filter lymph of harmful pathogens such as bacteria and viruses as well as cellular waste, dead cells, and cancerous cells.

They are also major sites of B and T cells and other white blood cells.

Question 12

What is the function of the spleen?

Answer 12

It mainly acts as a filter for purifying the blood, removing microbes and worn out or damaged red blood cells.

It is also an important organ in the immune system, producing the white blood cells that fight infection and synthesize antibodies.

Question 13

What is the function of mucus associated lymphoid tissue?

Answer 13

Initiates immune responses to specific antigens encountered along all mucosal surfaces

Question 14

What is the function of gut-associated lymphoid tissue?

Answer 14

T-cell lymphocytes, B-cell lymphocytes, and macrophages primarily inhabit Gut-Associated Lymphoid Tissue (GALT). The role of GALT is to block normal flora bacteria (bacteria that are normally present in the gastrointestinal tract to aid digestion) from penetrating into other tissues or the BLOOD circulation.

Question 15

What are some examples of an antigen-presenting cell and what is their role?

Answer 15

An antigen-presenting cell (APC) is an immune cell that detects, engulfs, and informs the adaptive immune response about an infection (present to T cells).

Examples of antigen-presenting cells are macrophages, B-cells and dendritic cells.

Question 16

What is an antigen-presenting cell?

Answer 16

An antigen-presenting cell (APC) is a cell that displays antigen complexed with major histocompatibility complexes (MHCs) on their surfaces; this process is known as antigen presentation. It stimulates an immune response.

Question 17

What are the two types of Antigen-presenting cells?

Answer 17

Fixed and mobile.

Question 18

What do mobile antigen-presenting cells do?

Answer 18

Transport antigen from peripheral tissues to lymphoid tissue.

Question 19

What is the arrangement of the lymph nodes?

Answer 19

T cells concentrate in the paracortex

B-cells are in and around germinal centres.

Plasma cells are present in the medulla.

Question 20

What are the two types of tissue the spleen contains and what are their functions?

Answer 20

White pulp- aka peri-arteriolar lymphatic sheath(PALS) which contains the majority of the lymphoid tissue.

Red pulp- filter the blood of antigens, microorganisms, and defective or worn-out red blood cells.

Question 21

1. Which of the following lymphocyte sub-types is primarily responsible for antibody production?
   a. B-cells
   b. Cytotoxic T-cells
   c. T-helper cells
   d. Natural Killer Cells

Answer 21

B cells

Question 22

What is clonal selection ?

a. Elimination of lymphocytes lacking a functional antigen receptor
b. A mechanism by which specific pathogens propagate by evading the immune system
c. The selection and propagation of lymphocytes that react with a particular pathogen
d. The identification and elimination of self-reactive lymphocytes

Answer 22

c. The selection and propagation of lymphocytes that react with a particular pathogen

Question 23

Which of the following cells plays an important role in targeting and eliminating virally infected cells?

a. Neutrophils
b. Macrophages
c. T-cells
d. B-cells

Answer 23

c. T-cells

Question 24

Which group of cytokines are key elements in the defence against viruses?

a. Interleukins
b. Tumour necrosis factors
c. Interferons
d. Colony stimulating factors

Answer 24

c. Interferons

Question 25

Which lymphocyte sub-type secretes cytokines that activate macrophages? a. Cytotoxic T-cells b. TH1 cells c. TH2 cells d. NK cells

Answer 25

b. TH1 cells

Question 26

. Which of the following cell types expresses MHC Class II molecules on their surface? a. NK cells b. Neutrophils c. Dendritic cells d. T-cells

Answer 26

c. Dendritic cells

Question 27

Which antibody class predominates in tear fluid and plays a role in antimicrobial defence of the ocular surface? a. IgG b. IgA c. IgM d. IgD

Answer 27

b. IgA

Question 28

Which class of antibody plays a major role Type I hypersensitivity reactions? a. IgG b. IgA c. IgD d. IgE

Answer 28

d. IgE

Question 29

What is the principal defence mechanism against bacterial toxins? Select one: a. Neutralisation by specific antibodies b. Complement binding c. Phagocytosis by neutrophils d. Proteolytic cleavage by enzymes released from phagocytes

Answer 29

a. Neutralisation by specific antibodies

Question 30

Which of the following regarding autoimmunity is false? a. It is often familial b. It can be organ-specific or non-organ-specific c. It represents a breakdown of the normal mechanisms for self-tolerance d. Autoantibodies are always a feature of autoimmune disease

Answer 30

d. Autoantibodies are always a feature of autoimmune disease

Question 31

Which type of hypersensitivity reaction causes tissue damage that is mediated principally by IgG or IgM antibodies? a. Type I b. Type II c. Type III d. Type IV

Answer 31

b. Type II

Question 32

In seasonal allergic conjunctivitis, what is the principal source of inflammatory mediators that are responsible for the signs and symptoms of the condition? a. Macrophages b. T -cells c. Eosinophils d. Mast cells

Answer 32

d. Mast cells

Question 33

What are the functions of antibodies?

Answer 33

Bind to pathogens and prevent them from entering/damaging body cells. neutralises bacterial toxins. activate complement Facilitates phagocytosis by opsonisation (this tags the pathogen and makes it easier to digest).

Question 34

What is the relationship between T-cells and the thymus?

Answer 34

Pre T-cells denied from stem cells in the bone marrow mature in the thymus. The thymus eliminates self reacting T-cells.

Question 35

What systems can lymphocytes travel through and why?

Answer 35

Both the vascular system and the lymphatic system. (Both systems run closely and parallel so cells and fluids can be exchanged)

Question 36

Where do all lymphocytes originate from?

Answer 36

Stem cells in the bone marrow however where they chose to mature is how they can be differentiated i.e whether they are b-cells or T-cells.

Question 37

What are primary and secondary lymphoid tissues?

Answer 37

Primary lymphoid tissues consist at the bone marrow and thymus. Secondary lymphoid tissues are those were lymphocytes activate, proliferate and differentiate.

Question 38

Where do B-lymphocytes develop for foetuses as a pose to adults?

Answer 38

They develop in the liver for foetuses and in the bone marrow for adults.

Question 39

What are antibodies on the surface of B-lymphocytes called?

Answer 39

immunoglobulins

Question 40

What are some key properties of T helper cells?

Answer 40

They have a CD4 receptor. Secrete cytokines, which regulate leukocyte division and differentiation. TH1 activate macrophages and TH2 help antibody responses.

Question 41

What are some key properties of T-cytotoxic cells?

Answer 41

They destroy virally infected cells or tumour cells . Express CD8 cell surface receptor. Recognise antigen associated with class 1 MHC molecules.