30 Questions
What is the primary function of Antigen-Presenting Cells (APCs)?
To engulf and digest antigens, and display a piece on their surface
Which of the following antibody classes is responsible for providing protection to the fetus?
IgG
What is the term for the specific region on an antigen's surface that immune components bind to?
Antigenic determinant
Which type of immunity involves the transfer of antibodies from one individual to another?
Passive immunity
What is the first antibody class released in response to an antigenic stimulus?
IgM
What is the primary function of the spleen in the lymphatic system?
Filtering and destroying bacteria in the blood
What is the main difference between the thymus and other lymphoid organs?
It functions strictly in T lymphocyte maturation
What is the primary function of MALT (Mucosa-associated lymphatic tissue)?
To destroy bacteria and prevent them from breaching the intestinal wall
What is the difference between innate and adaptive defenses?
Innate defenses are nonspecific, while adaptive defenses are specific
What is the primary function of macrophages in the lymph nodes?
To destroy microorganisms and debris
What is the primary function of the membrane attack complex (MAC) in complement activation?
Causing cell lysis
What is the benefit of fever in the context of immune response?
Sequestering iron and zinc in the liver and spleen
What is a characteristic of the adaptive immune response?
It has memory and is specific
What is the role of C3b in complement activation?
Opsonization and initiating the formation of the membrane attack complex
What is the function of pyrogens in the context of fever?
Secreted by macrophages and leukocytes to cause fever
What is the primary function of antigen-presenting cells?
To engulf and display antigens on their surface for recognition by immune components
Which class of antibodies is responsible for providing protection to the fetus?
IgG
What is the primary function of IgM antibodies?
To protect against bacteria, viruses, and toxins
What is the term for the specific region on an antigen's surface that immune components bind to?
Antigenic determinant
What is the primary difference between active and passive immunity?
Active immunity involves the production of antibodies, while passive immunity involves the transfer of antibodies
Which component of the complement system is responsible for initiating the formation of a membrane attack complex?
C3b
What is the primary mechanism by which fever restricts the growth of microorganisms?
By sequestering iron and zinc in the liver and spleen.
Which of the following is a characteristic of the humoral immune response?
It is specific to a particular pathogen.
What is the primary role of opsonization in the complement system?
To enhance phagocytosis.
Which of the following is a benefit of the adaptive immune response?
It amplifies the inflammatory response.
What is the primary function of Peyer's patches and the appendix in the lymphatic system?
To generate 'memory' lymphocytes and destroy bacteria
Which of the following is NOT a characteristic of the innate defense system?
Specific to particular pathogens
What is the primary function of macrophages in the lymph nodes?
To destroy microorganisms and debris
Which of the following is an example of a MALT?
Tonsils
What is the main difference between the first and second line of defense?
The first line of defense includes physical barriers, while the second line includes internal defenses
Study Notes
Cellular (Cell-Mediated) Immunity
- Antigens are substances that can mobilize adaptive defenses and provoke an immune response
- Antigens are large, complex molecules not normally found in the body (non-self)
- Antigenic determinants are multiple sites on an antigen's surface that immune components bind to
- Antigen processing and presentation involves antigen-presenting cells (APCs) engulfing, digesting, and displaying antigen fragments on their surface
Cells of the Adaptive Immunity
- All cells of the adaptive immunity are formed in red bone marrow
- Immunocompetent lymphocytes recognize specific antigens by binding to them
- B cells (lymphocytes) mature in red bone marrow, while T cells mature in the thymus
- Antigen-presenting cells (APCs) include dendritic cells and macrophages
Structure of Antibodies
- Five classes of antibodies/immunoglobulins: IgM, IgA, IgD, IgG, and IgE
- IgM: first antibody released, potent agglutinating agent
- IgA: in saliva, sweat, intestinal juices, and milk, stops pathogens from attaching to epithelial surfaces
- IgD: attached on B cells' surface, functions as a B cell receptor
- IgG: 75-85% of antibodies in plasma, protects against bacteria, viruses, and toxins, passed from pregnant mother to fetus
- IgE: active in some allergies and parasitic infections, causes mast cells and basophils to release histamine
Antibody Formation and Immunity
- Active versus passive immunity
- Adaptive immune response: specific, systemic, and has memory
- Two separate overlapping arms: humoral (antibody-mediated) immunity and cellular (cell-mediated) immunity
Lymph Nodes and Spleen
- Lymph nodes filter lymph and trap microorganisms and debris
- Circulation in lymph nodes: lymph enters via afferent lymphatic vessels, travels through subcapsular sinus and smaller sinuses, and exits via efferent vessels
- Spleen: site of lymphocyte proliferation and immune surveillance, cleanses blood of aged cells and platelets, stores breakdown products of RBCs, and contains lymphocytes, macrophages, and erythrocytes
Thymus and Tonsils
- Thymus: matures T lymphocytes, provides environment for T lymphocytes to become immunocompetent
- Tonsils: simplest lymphoid organs, trap and destroy bacteria and particulate matter, form a ring of lymphatic tissue around the pharynx
MALT and Immunity
- Mucosa-associated lymphatic tissue (MALT): Peyer's patches, tonsils, and appendix (digestive tract), lymphoid nodules in bronchi walls (respiratory tract)
- Protects digestive and respiratory systems from foreign matter
Immunity and Innate Defenses
- Immunity: resistance to disease
- Innate defenses: surface barriers (skin, mucous membranes), internal defenses (antimicrobial proteins, fever, inflammation, NK cells, phagocytes)
- Adaptive defenses: humoral immunity (B cells), cellular immunity (T cells), cooperation between the two defenses
Test your knowledge on cellular immunity, including antigens, antigenic determinants, and antigen processing and presentation. Learn about the different immune components and their functions in the adaptive immune response.
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