Biology

Human Immunity and Blood

2,096 Questions

Human immunity and blood questions cover the physiological mechanisms protecting the body against diseases and the components of blood. Topics include blood groups, cell mediated immunity, monoclonal antibodies, and blood coagulation. These biology topics frequently appear in general science sections of competitive exams.

Blood groupsCell mediated immunityMonoclonal antibodiesBlood coagulationCancer immunology

Human Immunity and Blood Questions

Multiple choice biology simple nutrients into cells blood and its components components of blood composition of blood

Which of the following helps to maintain the fluidity of the blood?

  1. Plasma

  2. RBC

  3. WBC

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

One half of blood is composed of red blood cells, white blood cells and platelets which are considered as solid part of blood and another half is composed of water, salts and proteins which is the fluid part of blood. The fluid part of blood is known as plasma. As the plasma consists of water it helps to maintain the fluidity of the blood.

So, the correct answer is 'Plasma'.

Multiple choice

What is the most common type of hypersensitivity reaction?

  1. Type I

  2. Type II

  3. Type III

  4. Type IV
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Type I hypersensitivity reactions, also known as immediate hypersensitivity reactions, are the most common type. They are mediated by IgE antibodies and mast cells, and can cause symptoms such as sneezing, runny nose, itchy eyes, and difficulty breathing.

Multiple choice

Which type of hypersensitivity reaction is caused by the binding of antibodies to cell surface antigens, leading to complement activation and cell lysis?

  1. Type I

  2. Type II

  3. Type III

  4. Type IV
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Type II hypersensitivity reactions, also known as cytotoxic hypersensitivity reactions, are caused by the binding of antibodies to cell surface antigens, leading to complement activation and cell lysis. This can occur in blood transfusions, when the recipient's antibodies attack the donor's red blood cells.

Multiple choice

What type of hypersensitivity reaction is characterized by the formation of immune complexes that deposit in tissues, leading to inflammation and tissue damage?

  1. Type I

  2. Type II

  3. Type III

  4. Type IV
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Type III hypersensitivity reactions, also known as immune complex hypersensitivity reactions, are characterized by the formation of immune complexes that deposit in tissues, leading to inflammation and tissue damage. This can occur in diseases such as lupus and rheumatoid arthritis.

Multiple choice

Which type of hypersensitivity reaction is mediated by T cells and involves a delayed response, typically taking several days to develop?

  1. Type I

  2. Type II

  3. Type III

  4. Type IV
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Type IV hypersensitivity reactions, also known as cell-mediated hypersensitivity reactions, are mediated by T cells and involve a delayed response, typically taking several days to develop. This type of reaction is involved in contact dermatitis and tuberculin skin tests.

Multiple choice

What is the role of mast cells in Type I hypersensitivity reactions?

  1. They release histamine and other inflammatory mediators.

  2. They produce antibodies.

  3. They activate complement.

  4. They phagocytose antigens.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mast cells play a crucial role in Type I hypersensitivity reactions by releasing histamine and other inflammatory mediators, such as leukotrienes and prostaglandins, upon activation by allergens.

Multiple choice

Which immunoglobulin is primarily involved in Type II hypersensitivity reactions?

  1. IgA

  2. IgD

  3. IgG

  4. IgM
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

IgG is the primary immunoglobulin involved in Type II hypersensitivity reactions, where antibodies bind to cell surface antigens and activate complement, leading to cell lysis.

Multiple choice

What is the complement system's role in Type III hypersensitivity reactions?

  1. It activates mast cells.

  2. It opsonizes pathogens for phagocytosis.

  3. It forms immune complexes with antigens.

  4. It directly lyses cells.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In Type III hypersensitivity reactions, the complement system plays a role in forming immune complexes with antigens, which can then deposit in tissues and cause inflammation.

Multiple choice

Which type of T cell is primarily involved in Type IV hypersensitivity reactions?

  1. Th1 cells

  2. Th2 cells

  3. Th17 cells

  4. Treg cells
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Th1 cells are the primary T cell subset involved in Type IV hypersensitivity reactions, where they release cytokines that activate macrophages and other immune cells to mediate delayed-type hypersensitivity responses.

Multiple choice

What is the mechanism of action of antihistamines in treating Type I hypersensitivity reactions?

  1. They inhibit the release of histamine from mast cells.

  2. They block the binding of IgE to mast cells.

  3. They activate the complement system.

  4. They suppress T cell responses.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Antihistamines work by inhibiting the release of histamine from mast cells, thereby reducing the inflammatory response associated with Type I hypersensitivity reactions.

Multiple choice

Which type of hypersensitivity reaction is characterized by the formation of granulomas?

  1. Type I

  2. Type II

  3. Type III

  4. Type IV
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Type IV hypersensitivity reactions, particularly delayed-type hypersensitivity reactions, are characterized by the formation of granulomas, which are collections of immune cells that surround and attempt to contain foreign substances or pathogens.

Multiple choice

What is the role of T regulatory cells (Tregs) in hypersensitivity reactions?

  1. They activate mast cells.

  2. They promote inflammation.

  3. They suppress immune responses.

  4. They directly kill pathogens.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

T regulatory cells (Tregs) play a crucial role in regulating immune responses and preventing excessive inflammation. In hypersensitivity reactions, Tregs can suppress immune responses and help maintain immune tolerance.

Multiple choice

Which type of hypersensitivity reaction is associated with contact dermatitis?

  1. Type I

  2. Type II

  3. Type III

  4. Type IV
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Type IV hypersensitivity reactions, specifically allergic contact dermatitis, are associated with contact dermatitis. This occurs when an individual comes into contact with an allergen, leading to a delayed-type hypersensitivity response characterized by skin inflammation and redness.

Multiple choice

What is the primary mechanism of desensitization in Type I hypersensitivity reactions?

  1. Blocking antibodies

  2. T cell suppression

  3. Mast cell degranulation

  4. Complement activation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Desensitization in Type I hypersensitivity reactions primarily involves the administration of blocking antibodies, which bind to allergens and prevent their interaction with IgE antibodies on mast cells, thereby reducing the release of inflammatory mediators.

Multiple choice

What is the term for the idea that our immune system can be overactive and attack our own tissues?

  1. Autoimmunity

  2. Allergy

  3. Asthma

  4. Eczema
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Autoimmunity is the idea that our immune system can be overactive and attack our own tissues, leading to a variety of health problems.