Immunity

Question 1

Immunity

Answer 1

The state of being resistance to injury, invading pathogens and foreign substances through defensive mechanisms in the body is known as immunity

Question 2

Immune responses in animals can be divided into two types

Answer 2

• Innate immunity
• Acquired immunity (Adaptive immunity)

Question 3

Innate immunity

Answer 3

Is also known as non specific defense
Found in both vertebrates and invertebrates
2 types known as external defense and internal defense

Question 4

External/ Barrier defenses

Answer 4

Considered as the 1st line of defense preventing the entry of pathogens from outside

Question 5

3 main external defenses

Answer 5

skin
Mucous membrane
Secretions by various organs

Question 6

4 major internal defenses

Answer 6

Phagocytic cells
Natural killer cells
Antimicrobial proteins
Inflammatory responses

Question 7

2 types of antimicrobial proteins

Answer 7

Interferons and Complement proteins

Question 8

Signs and symptoms of inflammation are

Answer 8

redness, heat, swelling and pain

Question 9

Interferons and complement proteins

Answer 9

Interferons are proteins secreted by virus-infected cells which protect uninfected cells from viral infection by interfering with viral replication.

Complement proteins are a group of proteins which are normally inactive in plasma and plasma membranes. Promotes phagocytosis and inflammatory responses.

Question 10

Pus

Answer 10

It is a fluid rich in dead phagocytes, dead pathogens and cell debris from the damaged tissue

Question 11

Phagocytes

Answer 11

Phagocytes are a type of white blood cell that use phagocytosis to engulf bacteria, foreign particles, and dying cells to protect the body
Neutrophils and macrophages

Question 12

Differences between macrophages and neutrophils

Answer 12

Macrophages are larger and more potent

Question 13

Types of white blood cells

Answer 13

Types of white blood cells are granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells)

Question 14

Acquired immunity shows

Answer 14

Specificity for particular foreign molecules
Recognition of animals own molecules from non-self molecules
memory for most previously encountered pathogens

Question 15

Maturation sites of B and T lymphocytes

Answer 15

B lymphocytes are matured in the red bone marrow while T lymphocytes are matured in the thymus

Question 16

Antigen

Answer 16

An antigen is a substance that has the ability to stimulate an immune response through T and B lymphocytes and to react with the specific cells or antibodies that is resulted from the stimulate immune response

Question 17

B and T lymphocytes are produced in the

Answer 17

Red bone marrow

Question 18

Examples for antigens

Answer 18

Viral proteins, bacterial toxins, bacterial structures, structural components of incompatible blood cells and transplanted tissues and cells

Question 19

Epitope

Answer 19

An epitope is a small accessible portion of the antigen which binds to a specific antigen receptor of a T lymphocyte or B lymphocyte

Question 20

Antibodies

Answer 20

Antibodies are proteins secreted by plasma cells (differentiated B lymphocytes) in response to specific antigens; the antibody binds with that antigen to neutralize, inhibit or destroy it.
Antibody-antigen complexes can activate complement system and phagocytosis to destroy the pathogen. Antibodies are also called as immunoglobulins

Question 21

Interferons

Answer 21

Interferons are proteins secreted by virus-infected body cells that protect uninfected host cells from viral infections by interfering with the viral replication

Question 22

Signalling molecules upon inflammation

Answer 22

Histamine (secreted by mastcells) and cytokines (by macrophages)

Question 23

Phagocytes

Answer 23

Macrophages and neutrophills

Question 24

Types of adaptive immunity

Answer 24

Cell mediated immunity
Humoral (antibody mediated) immunity

Question 25

Cells involved in cell mediated immunity

Answer 25

Carried out by T cells Cytotoxic T cells Helper T cells Memory T cells

Question 26

What are effector cells and memory cells

Answer 26

Effector cells fight against the infection (cytotoxic and helper) while memory cells maintains an immunological memory about the infection (memory T cells)

Question 27

Types of B lymphocytes involved in humoral immune responses

Answer 27

Plasma cells which produce antibodies Memory B cells

Question 28

Antigen presenting cells

Answer 28

Macrophages, dendritic cells and B cells

Question 29

Steps followed during adaptive immunity

Answer 29

1. Recognition of the antigen by B and T lymphocytes resulting in the activation (sensitization) of B and T lymphocytes 2. Proliferation and differentiation into effector cells. 3. Elimination of invaders 4. Provide immunological memory

Question 30

Active immunity

Answer 30

Immunity developed within the body due to the activation of B and T lymphocytes after a natural or an artificial infection (vaccination)

Question 31

Passive immunity

Answer 31

Short term immunity developed within the body due to transfer of antibodies artificially or from mother’s blood to the fetus and through colostrum and breastmilk through breast feeding.

Question 32

Allergens

Answer 32

Antigens capable of inducing a hypersensitive reactions in some persons. Most allergens stimulate plasma cells which produce antibodies specific to the antigen. When the allergen enter the body later, it binds with the antibody and stimulates the release of histamine and other inflammatory chemicals.

Question 33

Allergies

Answer 33

Exaggerated responses of the body due to certain antigens (allergens)

Question 34

Autoimmune disease

Answer 34

Resulted due to the sensitisation of immune system against self molecules

Question 35

E.g; Autoimmune diseases

Answer 35

Type-1 Diabetes mellitus Multiple sclerosis Rheumotoid arthritis

Question 36

Methods of attacking self tissues

Answer 36

By producing antibodies By activation of cytotoxic T cells

Question 37

Type-1 Diabetes mellitus

Answer 37

Resulted due to the activation of cytotoxic T cells destroying beta cells producing insulin hormone.

Question 38

Multiple sclerosis

Answer 38

Cytotoxic T cells attack and destroy myelin sheath (Schuwann cells) around neurones affecting the transmission of nerve impulses.

Question 39

Rheumatoid arthritis

Answer 39

Antibodies are produced against tissues surrounding the joints resulting in the erosion of the joint cartilage, bones and swelling of joints.

Question 40

Immunodeficiency disease

Answer 40

Disorder in which responses of the immune system to antigens are defective or absent.

Question 41

Secretions giving acidity to the skin

Answer 41

Secretions of sweat and sebaceous glands of the skin

Question 42

Acquired immunity

Answer 42

Acquired immunity is the ability of the body to defend itself against invading foreign agents (e.g. pathogens) through specific defense responses mediated by diverse T lymphocytes and B lymphocytes.

Question 43

Places where mucous membrane can be found

Answer 43

Lining of nasal tract Digestive tract Urinary tract Reproductive tract

Question 44

Secretions involved in external defences

Answer 44

Tears, saliva, mucus, perspirations of sweat, gastric juice and sebum (oil secreted by sebaceous glands)

Question 45

Complement proteins

Answer 45

Normally inactive proteins in the blood plasma and plasma membrane. When they are activated by different substances present on the surface of microbes, a cascade of biochemical reactions occurs which lead to lysis of invaded cells. They also promote phagocytosis and inflammatory responses.

Question 46

Main types of immunodeficiency Diseases

Answer 46

Inborn immunodeficiency Acquired immunodeficiency

Question 47

Inflammatory response

Answer 47

Innate immune defence response in the body to tissue damage triggered by microbial infections or injury of the tissue

Question 48

Antigen receptors

Answer 48

Specific protein receptors which have the ability to recognise specific foreign invasions.