Immune System Flashcards

Questions and Answers

Which of the following is NOT a characteristic of Natural Killer (NK) cells?

NK cells recognize abnormal or cancer cells by a specific antigen on their cell membrane. (correct)

NK cells attack infected or cancerous cells.

NK cells attack transplanted organs.

NK cells induce the target cell to undergo 'apoptosis' (cell suicide).

Which of the following innate internal defenses work by interfering with viral replication?

Phagocytes

T lymphocytes

Interferons (correct)

Complement proteins

How do phagocytes recognize foreign cells or bacteria?

All the foreign cells or bacteria are marked with opsonins that the phagocytes recognize.

Phagocytes recognize a specific antigen on the cell surface.

The phagocytes look for the absence of 'self' proteins.

The phagocytes recognize molecules on pathogens not normally found on body cells. (correct)

Which of the innate defense mechanisms can lyse bacteria and mark cells for phagocytosis?

Complement proteins Signup and view all the answers

Which of the following can act as opsonins on bacteria, thus enhancing phagocytosis?

Antibodies and complement proteins Signup and view all the answers

What constitutes the body's first line of defense against disease?

Intact skin and mucous membranes Signup and view all the answers

How do interferons protect against infection in healthy cells?

Interferons block viral reproduction in healthy cells through the production of antiviral proteins. Signup and view all the answers

What is the specific target of interferons?

Nearby healthy cells Signup and view all the answers

Which of the following is an effect of complement activation?

Opsonization Signup and view all the answers

What types of antigen are recognized by T cells?

Processed fragments of protein antigens displayed on surfaces of body cells Signup and view all the answers

Which of the following is not characteristic of the adaptive immune system?

It is specific for a given organ. Signup and view all the answers

How does a lymphocyte become immunocompetent?

Lymphocytes must be able to recognize their one specific antigen by binding to it. Signup and view all the answers

Which of the following statements does NOT describe the adaptive immune response?

It occurs immediately after the body is challenged by foreign material. Signup and view all the answers

Which of the following exemplifies passive immunity?

Antitoxin Signup and view all the answers

Which of the following best illustrates artificially acquired active humoral immunity?

Vaccines Signup and view all the answers

Select the correct statement about the function of antibodies.

Complement fixation is the main mechanism by which antibodies provide protection. Signup and view all the answers

Study Notes

Natural Killer (NK) Cells

NK cells do not recognize abnormal or cancer cells by specific antigens on their membranes; instead, they utilize broad recognition mechanisms.
Primary functions include attacking infected or cancerous cells and inducing apoptosis in target cells.

Innate Internal Defenses

Interferons inhibit viral replication and act specifically on healthy cells to block infections.

Phagocytes

Recognition of foreign cells by phagocytes is based on identifying unique molecules not present on normal body cells.

Complement Proteins

Complement proteins can lyse bacteria and assist in marking cells for phagocytosis, enhancing immune response.

Opsonins

Antibodies and complement proteins act as opsonins to enhance the phagocytosis process of bacteria.

First Line of Defense

The body’s primary defense against disease consists of intact skin and mucous membranes, acting as barriers to pathogens.

Interferon Functionality

Interferons protect healthy cells by producing antiviral proteins that block viral replication.

Targeting of Interferons

Interferons specifically target nearby healthy cells to provide protection against viral infections.

Effects of Complement Activation

One major effect of complement system activation is opsonization, which helps mark pathogens for destruction.

T Cell Antigen Recognition

T cells recognize processed fragments of protein antigens displayed on the surfaces of body cells rather than free-floating antigens.

Characteristics of the Adaptive Immune System

The adaptive immune system is antigen-specific, possesses memory, and operates systemically; it is not specific for a given organ.

Immunocompetence of Lymphocytes

For a lymphocyte to become immunocompetent, it must specifically recognize its corresponding antigen through binding.

Adaptive Immune Response

The adaptive immune response is not immediate; it takes time to develop after the body encounters foreign material.

Passive Immunity

Passive immunity is exemplified by the use of antitoxins, which provide immediate protection without the host's immune response being activated.

Artificially Acquired Active Immunity

The best example of artificially acquired active humoral immunity is through vaccines, which stimulate the immune system to produce its own antibodies.

Function of Antibodies

Complement fixation is a key protective mechanism employed by antibodies against pathogens, allowing for efficient immune response.

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Description

Test your knowledge on the characteristics of Natural Killer (NK) cells with these flashcards. Learn what distinguishes NK cells and their functions in attacking infected or cancerous cells. Perfect for mastering concepts in anatomy and physiology.