Introduction to Immunology

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Questions and Answers

What is the primary function of the complement system in the immune response?

To activate T cells

To produce antibodies

To recruit phagocytes to the site of infection

To recognize and bind to bacteria, marking them for destruction (correct)

What is the term for the process by which phagocytic cells engulf and digest foreign particles and microorganisms?

Phagocytosis (correct)

Pinocytosis

Endocytosis

Exocytosis

What is the main difference between innate and adaptive immunity?

Innate immunity is long-term, while adaptive immunity is short-term

Innate immunity is only found in vertebrates, while adaptive immunity is found in all animals

Innate immunity is specific to a particular pathogen, while adaptive immunity is not

Innate immunity is immediate, while adaptive immunity takes time to develop (correct)

Which of the following is NOT a type of cell involved in the innate immune response?

T cells Signup and view all the answers

What is the function of the opsonin in the complement system?

To mark pathogens for destruction by phagocytic cells Signup and view all the answers

What is the term for the process by which the immune system recognizes and responds to pathogens?

Immune response Signup and view all the answers

What is the role of C3a and C5a in the complement system?

To recruit phagocytes to the site of infection Signup and view all the answers

Which of the following is an example of a physical barrier that prevents the entry of pathogens into the body?

Skin and mucous membranes Signup and view all the answers

What is the definition of immunology?

The study of physiological mechanisms that humans and other animals use to defend their bodies from invasion by all sorts of other organisms Signup and view all the answers

What is an immunogen?

A molecule that stimulates the immune system to produce a response Signup and view all the answers

What is an epitope?

The part of the antigen that reacts with immune effector cells or soluble antibodies Signup and view all the answers

What are the 4 main types of pathogens?

Bacteria, Viruses, Fungi, Parasites Signup and view all the answers

What are the components of blood in the immune system?

Red blood cells, Plasma, White blood cells, Platelets Signup and view all the answers

What is haematopoiesis?

The process of formation of blood cells Signup and view all the answers

What are the 3 classifications of myeloid cells?

Granulocytes, Antigen presenting cells, Mast cells Signup and view all the answers

What are the 2 classifications of lymphoid cells?

Small lymphocytes, Large lymphocytes Signup and view all the answers

What are the 2 types of lymphoid organs?

Primary and Secondary Signup and view all the answers

Where do immature T cells migrate to complete their maturation?

Thymus Signup and view all the answers

Where are lymphocytes produced and matured?

Primary lymphoid tissues Signup and view all the answers

What is the function of lymph nodes?

To activate mature lymphocytes to respond to pathogens Signup and view all the answers

What happens to pathogens in lymph nodes?

They are trapped by dendritic cells and macrophages Signup and view all the answers

What happens to the lymph node during an infection?

It increases in size Signup and view all the answers

What is MALT?

A type of secondary lymphoid tissue Signup and view all the answers

Where are MALT tissues located?

In submucosal layers of various tracts Signup and view all the answers

What is the function of lymphatic vessels?

To collect and return plasma fluid to blood vessels Signup and view all the answers

Where do circulating lymphocytes move to in response to infection?

Lymph nodes Signup and view all the answers

What is the main function of phagocytosis?

Remove offending agents from the body Signup and view all the answers

What enhances the efficiency of phagocytosis?

Opsonin receptors Signup and view all the answers

What is the result of the phagosome fusing with a lysosomal granule?

Killing and degradation of the particle Signup and view all the answers

What is the function of cytokines?

Stimulate or inhibit the activity of other cells Signup and view all the answers

Which of the following is NOT a subgroup of cytokines?

Hormones Signup and view all the answers

Which cells produce cytokines in response to infectious agents?

Macrophages Signup and view all the answers

What is the function of stimulators of haematopoiesis?

Stimulate the growth and differentiation of immature leukocytes Signup and view all the answers

Which of the following is NOT a function of cytokines?

Removal of offending agents from the body Signup and view all the answers

Study Notes

Immune System Basics

Immunology is the study of physiological mechanisms used to defend the body against invasion by other organisms.
The immune system is crucial to human survival, and its absence can lead to fatal infections.
An immunogen is a molecule that stimulates the immune system to produce a response, which is then recognized by immune effector cells or soluble antibodies as an antigen.
An epitope is the part of the antigen that reacts with immune effector cells or soluble antibodies.

Pathogens

A pathogen is any organism with the potential to cause a disease.
There are four main types of pathogens: bacteria, viruses, fungi, and parasites (worms).

Immune System Components

The immune system consists of cells and tissues that work together to defend the body.
The immune system in the blood includes red blood cells, plasma, white blood cells (leukocytes), and platelets.
Haematopoiesis is the process of blood cell formation.
Myeloid cells can be classified into three categories: granulocytes (neutrophils, eosinophils, basophils), antigen-presenting cells (monocytes, macrophages, dendritic cells), and mast cells.
Lymphoid cells can be classified into two categories: small lymphocytes (B cells, T cells) and large lymphocytes (NK cells).

Lymphoid Organs

Primary lymphoid organs include bone marrow and the thymus, where lymphocytes are produced and matured.
Secondary lymphoid organs include the spleen, adenoids, tonsils, appendix, and lymph nodes, where mature lymphocytes are activated to respond to invading pathogens.

Primary Lymphoid Tissues

Bone marrow is a soft, spongy tissue that fills the internal cavity of bones, where B cells originate and mature, and T cells originate but leave at an immature stage.
The thymus is located above the heart, where immature T cells migrate to complete their maturation, progressing from the cortex to the medulla.

Secondary Lymphoid Tissues

Lymph nodes are sites where mature lymphocytes are activated to respond to invading pathogens, and where they can meet and interact with pathogens.
Lymph nodes are connected by a network of lymphatic vessels, which collect plasma fluid that leaks out from blood vessels and return it to the blood vessels via the thoracic duct.
Circulating lymphocytes can move from blood capillaries to lymph nodes, where they can encounter pathogens.

Innate Immunity

Innate immunity provides immediate, non-specific defense against infection, with a rapid response (hours) and no memory.
Cells of innate immunity include macrophages, NK cells, and dendritic cells.
Phases of the immune response include immediate innate immune response, induced innate immune response, and adaptive immunity.

Immediate Innate Immune Response

Barriers (physical and chemical) prevent entry of pathogens.
Antimicrobial peptides are produced in response to infection.
The complement system is a group of nearly 30 serum and membrane proteins that act in an orderly sequence to provide defense against infection.

Induced Innate Immune Response

Phagocytosis is the process of engulfment and removal of pathogens by cells such as neutrophils and macrophages.
Cytokines production and inflammation occur in response to infection.
Toll-like receptors are activated in response to pathogens.
NK cells are involved in the induced innate immune response.

Phagocytosis

Phagocytosis is the process of removal of offending agents through recognition and attachment, engulfment, and killing and degradation.
Opsonin receptors enhance the efficiency of phagocytosis.
Lysosomal enzymes are involved in the killing and degradation of pathogens.

Cytokines

Cytokines are low-molecular-weight proteins that stimulate or inhibit the activity, proliferation, or differentiation of other cells.
There are around 20 different cytokines, including interferons, lymphokines, interleukins, and chemokines.
Cytokines are produced by cells such as macrophages and T lymphocytes in response to infection or specific recognition of foreign antigens.

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Description

Learn the basics of immunology, including cells and tissues of the immune system and mechanisms of the innate immune system. Define what immunology is and its importance in defending the body against invasions.