IMMUNE SYSTEM

Question 1

WHAT IS IMMUNITY ?

Answer 1

Immunity is concerned with the recognition
and disposal of foreign or ‘non-self’ materials that enter the body , usually in the form of life-threatening infectious micro-organisms but sometimes, unfortunately in the shape of a life saving kidney graft.

Question 2

WHAT IS IMMUNOLOGY ?

Answer 2

Immunology is the study of the organs, cells, and molecules responsible for the recognition and disposal[immune system], how they interact, the consequences weather desirable or otherwise of their activities and ways in which they can be advantageously increased or reduced.

Question 3

WHAT IS THE IMMUNE SYSTEM ?

Answer 3

Immune system is the body’s natural defence system that helps fight infections.

Question 4

WHAT DOES ‘SELF’ REFER TO IN TERMS OF IMMUNE SYSTEM ?

Answer 4

It refers to particles, such as proteins and other molecules, that are a part, or made by one’s body. they can be found circulating in the blood or attached to different tissues. Not targeted or destroyed by the immune system.

Question 5

WHAT DOES ‘TOLERANCE’ REFER TO IN TERMS OF IMMUNE SYSTEM ?

Answer 5

the non reactivity of the immune system to self particles.

Question 6

WHAT DOES ‘NON-SELF’ REFER TO IN TERMS OF IMMUNE SYSTEM ?

Answer 6

It refers to particles that are not made by the body and are recognised as potentially harmful. These are often called foreign bodies. They can be bacteria, viruses, parasites, pollens, dust and toxic chemicals.

Question 7

WHAT DOES ‘ANTIGENS’ REFER TO IN TERMS OF IMMUNE SYSTEM ?

Answer 7

substances capable, under appropriate condition, of inducing the formation of antibodies and reacting specifically with the antibodies produced. They are divided into hetero-antigens and auto-antigens.

Question 8

WHAT ARE EPITOPES ?

Answer 8

portions of the antigen molecules which are responsible for specificity of the antigens in antigen-antibody (Ag-Ab) reactions and that combine with the antigen binding site of Ab, to which they are complementary.

Question 9

WHAT ARE PARATROPES ?

Answer 9

Sites of antigen binding on antibody molecule.

Question 10

WHAT ARE HETERO-ANTIGENS ?

Answer 10

foreign antigens originating from outside the body. examples include parts of, or substances produced by non self particles.

Question 11

WHAT ARE AUTO-ANTIGENS ?

Answer 11

antigens that originate from the body. an anomaly that occurs in persons with autoimmune disorders e.g. Addison’s disease, myasthenia gravis

Question 12

WHAT ARE ANTIBODIES ?

Answer 12

proteins produced by the immune system in response to the presence of antigen.

Question 13

WHAT IS IMMUNOLOGICAL MEMORY ?

Answer 13

It refers to the ability of the immune system to respond more rapidly and effectively to a pathogen that has been previously encountered.

Question 14

WHAT IS VACCINATION ?

Answer 14

a method of stimulating the adaptive immune response and generating memory and acquired resistance without suffering the full effect of the disease

Question 15

WHAT IS HYPERSENSITIVITY ?

Answer 15

It is a set of undesirable reactions produced by the normal immune system. occurs as a result of re-exposure to a previous stimulus. e.g. allergy

Question 16

WHAT ARE THE COMPONENTS OF THE IMMUNE SYSTEM ?

Answer 16

-The lymphatic system made up of the lymph nodes and vessels.
-The bone marrow made up of the red marrow which produces RBCs AND WBCs as well as platelets. And the yellow marrow.
-The spleen: filters the blood by removing old or damaged blood cells and platelets and helps the immune system by destroying bacteria and other foreign substances .
-The tonsils and thymus, which make the antibodies.

Question 17

WHAT IS INNATE IMMUNITY

Answer 17

It is the first line of defence
It is made up of defences against infections that can be activated immediately once a pathogen attacks.

Question 18

WHAT KIND OF IMMUNITY IS NON-SPECIFIC

Answer 18

INNATE IMMUNITY

Question 19

WHAT DOES THE INNATE/NATURAL IMMUNITY CONSIST OF ?

Answer 19

Physical barriers; such as skin, G.I tracts,
respiratory tract, naso-pharynx, cilia.

Defence mechanism; such as secretions, saliva, lysozyme ( found in tears and sweat), gastric acid, mucous, bile, lactic acid (found in vaginal and urinary tract).

General immune responses; such as inflammation responses, complements, nonspecific cellular responses. These inflammatory responses actively bring cells to the site of an infection by increasing blood flow to the area while complement marks pathogens for destructions by making holes in the cell membrane of the pathogen.

Question 20

WHAT ARE THE CELLS OF THE INNATE IMMUNE SYSTEM

Answer 20

Phagocytes or phagocytic cells
Macrophages
Mast cells
Eosinophils
Neutrophils
Basophils
Natural killer cells
Dendritic cells

Question 21

WHAT ARE DENDRITIC CELLS ?

Answer 21

Dendritic cells are antigen- presenting cells that are located in tissues, and can contact external environments through the skin, the inner mucosal lining of the nose, lungs, stomach, and intestines. Since dendritic cells are located in tissues that are common points for initial infection, they can identify threats and act as messengers for the rest of the immune system by antigen presentation. Dendritic cells also act as bridge between the innate immune system and the adaptive immune system.

Question 22

WHAT ARE NATURAL KILLER CELLS ?

Answer 22

They do not attack pathogens directly, rather they destroy infected host cells in order to stop the spread of an infection. Infected or compromised host cells can signal natural killer cells for destruction.

Question 23

WHAT ARE BASOPHILS ?

Answer 23

granulocytes that attack multicellular parasites.

Question 24

WHAT ARE PHAGOCYTES / PHAGOCYTIC CELLS ?

Answer 24

They circulate throughout the body, looking for potential threats like bacteria and viruses to engulf and destroy.

e.g. Macrophages, Leukocytes, lymphocytes, granulocytes, monocytes.

Question 25

WHAT ARE NEUTROPHILS ?

Answer 25

They are phagocytic cells that are also classified as granulocytes as they contain granules in their cytoplasm which are toxic to bacteria and fungi and prevent them from proliferating or die on contact

Question 26

WHAT ARE EOSINOPHILS ?

Answer 26

They are granulocytes, secrete a range of highly toxic proteins and free radicals that kill bacteria and parasites. Use of these toxic proteins and free radicals also cause tissue damage during allergic reactions, thus their activation and toxin release is highly regulated to prevent unnecessary tissue damage.

Question 27

WHAT ARE MAST CELLS ?

Answer 27

They are found in mucous membrane and connective membrane and are important. They are involved in inflammatory responses.

When activated, they release cytokines and granules that contain chemical molecules which create inflammatory cascade.

Question 28

WHAT ARE MACROPHAGES ?

Answer 28

They are efficient phagocytic cells that leave the circulatory system by moving across the walls of capillary vessels. They can also release cytokines in order to signal and recruit other cells to an area with pathogens.

Question 29

WHAT IS ADAPTIVE IMMUNITY ?

Answer 29

Uses specific antigens to strategically mount an immune response

It is based on the special properties of lymphocytes(T & B) which can respond selectively to thousands of different non-self materials, or antigens.

This leads to specific memory and a permanently altered pattern of response.
Slower to respond to threats and infections than the innate immunity.

Question 30

WHAT IMMUNITY IS SPECIFIC IN NATURE ?

Answer 30

ACQUIRED/ ADAPTIVE IMMUNITY.

Question 31

WHAT CELLS DOES ADAPTIVE IMMUNITY DEPEND ON ?

Answer 31

B CELLS AND T CELLS
Both are lymphocytes that are derived from specific types of stem cells, called multipotent hematopoietic stem cells, in the bone marrow, they need to mature and become activated.