Slide Set: 8: Immune System Flashcards Preview

*Mammalian Physiology > Slide Set: 8: Immune System > Flashcards

Flashcards in Slide Set: 8: Immune System Deck (162)
Loading flashcards...
1

The immune system serves three major functions:

1. It tries to recognize and remove abnormal “self” cells created when normal cell growth and development go wrong.
2. It removes dead or damaged cells, as well as old red blood cells.
3. It protects the body from disease-causing invaders known as pathogens.
4. attempts to recognize and remove abnormal cells

2

Substances that trigger the body’s immune response are called _________

immunogens

3

Immunogens that react with products of the response are known as ___________.

antigens

4

Pathologies of the immune system generally fall into one of three categories:

incorrect responses,
overactive responses,
lack of response.

5

Incorrect responses

Autoimmune diseases

If mechanisms for distinguishing self from non-self fail and the immune system attacks the body’s normal cells, an autoimmune disease results.

Type 1 diabetes mellitus, in which proteins made by immune cells destroy pancreatic beta cells, is an example of an autoimmune disease in humans.

6

Overactive responses

Allergies

are conditions in which the immune system creates a response that is out of proportion to the threat posed by the antigen. In extreme cases, the systemic effects of allergic responses can be life threatening.

7

Lack of immune response

Immunodeficiency diseases
arise when some component of the immune system fails to work properly.

Primary immunodeficiency is a family of genetically inherited disorders that range from mild to severe.

Acquired immunodeficiencies may occur as a result of infection, such as acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV). Acquired immunodeficiencies may also arise as a side effect of drug or radiation therapy, such as those used to treat cancer.

8

Primary immunodeficiency

is a family of genetically inherited disorders that range from mild to severe.

9

Acquired immunodeficiency

Acquired immunodeficiencies may occur as a result of infection, such as acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV). Acquired immunodeficiencies may also arise as a side effect of drug or radiation therapy, such as those used to treat cancer.

10

What are the differences between bacteria and viruses?

1. Structure
- Bacteria are cells, with a cell membrane that is usually surrounded by a cell wall. Some encapsulated bacteria also produce an additional protective outer layer known as a capsule.
- Viruses are not cells. They consist of nucleic acid (DNA or RNA) enclosed in a coat of viral proteins called a capsid. Some viruses add an envelope of phospholipid and protein made from the host’s cell membrane and incorporate viral proteins into the envelope

2. Living conditions and reproduction.
- Most bacteria can survive and reproduce outside a host if they have the required nutrients, temperature, pH, and so on.
-Viruses must use the intracellular machinery of a host cell to replicate. The location of pathogens in both major compartments of the body requires different defense mechanisms for each compartment.

3. Susceptibility to drugs
- Most bacteria can be killed by the drugs we call antibiotics. These drugs act directly on bacteria and destroy them or inhibit their growth.
- Viruses cannot be killed by antibiotics. A few viral infections can be treated with antiviral drugs, which target specific stages of viral replication.

11

Viruses are not cells. They consist of nucleic acid (DNA or RNA) enclosed in a coat of viral proteins called a ____

capsid.

12

Some encapsulated bacteria also produce an additional protective outer layer known as a ____.

capsule

13

Viruses can be released from host cells in one of two ways:

(1) The virus causes the host cell to rupture, releasing virus particles into the ECF, or

(2) virus particles surround themselves with a layer of host cell membrane and then bud o from the surface of the host cell.

14

The body has two lines of defense:

physical and chemical barriers, such as skin, mucus, and stomach acid, first try to keep pathogens out of the body’s internal environment

If this first line of defense fails, then the internal immune response takes over.

15

The internal immune response has four basic steps:

(1) detection and identification of the foreign substance,
(2) communication with other immune cells to rally an organized response,
(3) recruitment of assistance and coordination of the response among all participants, and
(4) destruction or suppression of the invader.

16

The immune response is distinguished by its extensive use of chemical signaling. Detection, identification, communication, recruitment, coordination, and the attack on the invader all depend on signal molecules such as _________

cytokines and antibodies.

17

What are cytokines?

Cytokines are protein messengers released by one cell that affect the growth or activity of another cell

18

What are antibodies?

Antibodies, proteins secreted by certain immune cells, bind antigens and make them more visible to the immune system.

19

The human immune response is generally divided into two categories:

nonspecific innate immunity and speci c acquired im- munity.

20

Innate immunity

Innate immunity is present from birth {innatus, inborn} and is the body’s nonspecific immune response to invasion.

The membrane receptors that mediate innate immunity have broad specificity and allow some immune cells to respond to molecular signals that are both unique and common to pathogenic microorganisms.
An example of a common pathogen-specific signal would be certain components of the bacterial cell wall. Because the nonspecific innate response does not target a particular pathogen, it begins within minutes to hours.

21

What is inflammation?

apparent on the skin as a red, warm, swollen area, is a hallmark reaction of cytokine-mediated innate immunity.

22

Acquired immunity

Acquired immunity (also called adaptive immunity) is directed at specific invaders and for this reason is the body’s speci c immune response. e membrane receptors that medi- ate acquired immunity are highly speci c and can distinguish between different pathogens. One characteristic of acquired immunity is that a specific immune response following rst ex- posure to a pathogen may take days. With repeated exposures, however, the immune system “remembers” prior exposure to the pathogen and reacts more rapidly.

23

Acquired immunity can be divided into

cell-mediated immunity and humoral immunity.

24

Cell-mediated immunity

uses contact-dependent signaling in which an immune cell binds through receptors to its target cell.

25

Humoral immunity

also known as antibody-mediated immunity, uses the secreted pro- teins known as antibodies to carry out the immune response. Antibodies combine with foreign substances to make them more visible to the cells of the immune system.

26

The immune system has two anatomical components:

lymphoid tissues and the cells responsible for the immune response.

27

Lymphoid tissues

are found all over the body. The two primary lymphoid tissues are the thymus gland and the bone marrow, both sites where cells involved in the immune response form and mature. Some types of mature immune cells do not specialize until their first exposure to the pathogen they will fight. These mature but unspecialized immune cells are said to be naïve cells

28

secondary lymphoid tissues

mature immune cells interact with pathogens and initiate a response.

29

secondary tissues are divided into

encapsulated tissues and unencapsulated diffuse lymphoid tissues.

30

encapsulated lymphoid tissues

The encapsulated lymphoid tissues are the spleen and the lymph nodes. Both spleen and lymph nodes have an outer wall formed from fibrous collagenous capsules.