What does the lymphatic system do?

Returned fluids that leaked from the vessels back to the blood system

What are the three parts that the lymphatic system consists of?

1. Network of lymphatic vessels

2. Lymph (fluid in the vessels)

3. Lymph organs and tissues (cleanse lymph: Lymph nodes)

The lymphatic system provides structural basis of what?

Immune system to protect against diseases

The lymph system houses what kinds of cells?

phagocytic cells and lymphocytes

What structures are included in the lymph system?

Spleen

Thymus

Tonsils

Lymph nodes

Other lymphoid tissues

What two ways does the immune system defenses work?

Specific and nonspecific

In this immune system defense, lymphocytes are the main drive, involves identification, attacking, and developing an immunity to a specific pathogen.

Specific

In this immune system defense, it blocks and defends against any pathogen and cannot distinguish one attack from another.

Nonspecific

This is a fluid similar to plasma but it doesn't have the plasma proteins.

Lymph

These carry lymph from peripheral tissues to the venous system.

Lymphatic vessels

What is the function of the lymphatic system regarding lymphocytes?

To maintain, produce, and distribute

Where are lymphocytes produced?

in lymphoid tissues

in lymphoid organs

in red bone marrow

Why are lymphocytes distributed through out the body?

to detect problems

to travel to the site of an injury or infection

This is the blockage of lymph drainage from a limb and causes severe swelling as well as interfering with the immune system function.

Lymphedema

Lymphocytes make up how much of the circulating leukocytes?

20-30%

Are most lymphocytes stored or circulating?

Stored

What are the three types of lymphocytes?

T cells

B cells

NK cells

Of the circulating lymphocytes, what kind is the most numerous?

T cells (80%)

What are the three main kinds of T cells?

Cytotoxic T cells

Helper T cells

Memory T cells

This kind of T cell attacks cells infected by viruses and produce cell-mediated immunity.

Cytotoxic T cells

This kind of T cell stimulates the function of T cells and B cells.

Helper T cell

This kind of T cell is formed in response to foreign substances and remain in the body to give immunity.

Memory T cells

What are the two less common types of T cells?

Inflammatory T cells

Suppressor/inducer T cells

B cells make up what percentage of circulating leukocytes?

10-15%

B cells differentiate or change into what kind of cells?

Plasma cells

Plasma cells produce and secrete what?

Antibodies (immunoglobulin proteins)

Define antigen.

Targets that identify any pathogen or foreign compound

The binding of a specific antibody to its specific target antigen initiates what?

antibody-mediated immunity

Give another name for Natural Killer (NK) cells.

Large granular lymphocytes

NK cells are responsible for _________ surveillance.

immunological

These cells (lymphocytes) attack foreign cells, virus-infected cells, and cancer cells.

Natural Killer (NK) Cells

Lymphocyte production is also known as what?

lymphopoiesis

In bone marrow, cells called _________ divide into two types of lymphoid stem cells.

Hemocytoblasts

These two types of lymphocytes migrate throughout the body to defend peripheral tissues and retain their ability to divide.

T and B cells

This is a connective tissue dominated by lymphocytes.

Lymphoid tissue

This is an areolar tissue with densely packaged lymphocytes and germinal center that contains dividing lymphocytes.

Lymphoid nodules

Where are lymphoid nodules distributed at?

Lymph nodes

spleen

respiratory tract (tonsils)

along digestive, urinary and reproductive tracts

This is lymphoid tissue associated with the digestive system.

Mucosa-Associated Lymphoid Tissue (MALT)

MALT is made up of what?

aggregated lymphoid nodules clustered deep into intestinal epithelial lining

This organ contains a mass of fused lymphoid nodules.

Appendix

List the 5 tonsils in the wall of the pharynx.

Left and right palatine tonsils

Pharyngeal tonsils (adenoid)

Two lingual tonsils

The lymphoid organs (lymph nodes, thymus, spleen) are separated from surrounding tissues by what?

a fibrous connective tissue capsule

Give the passage of lymph flow through a lymph node in a network of sinus.

Subscapular space

through outer cortex

through deep cortex

through the core

into hilum and efferent lymphatics

The subscapular space contains what two cells?

Macrophages

dendritic cells

The outer cortex of a lymph node contains what cells in the germinal centers?

B cells

The deep cortex of a lymph node is dominated by what kind of cell?

T cells

The core or medulla of the lymph node contains what kinds of cells?

B cells and plasma cells, organized into medullary cords

When lymph is filtered, what is removed?

Debris

pathogens

99% of antigens

What happens in the first step of immune response when an antigen is presented?

Extracted antigens are "presented" to lymphocytes or attached to dendritic cells to stimulate lymphocytes

What do the lymph nodes of the gut, trachea, lungs, and thoracic duct do?

Protect against pathogens in the digestive and respiratory systems.

Lymph nodes are actually what?

Glands

Why do lymph nodes swell up?

in response to inflammation

What is the term for chronic or excessive enlargement of the lymph nodes?

Lymphadenopathy

What can lymphadenopathy indicate?

infections, endocrine disorders, or cancer

The atrophy of the thymus gland after puberty has what effect on the immune system?

diminishes the effectiveness

Body defenses provide ________ to fight infection, illness, and disease.

resistance

What are the two categories of defense?

Innate (nonspecific) defenses

Adaptive (specific) defenses

This kind of defense always works the same way, against any type of invader, and is a nonspecific resistance.

Innate

This kind of defense protects against specific pathogens, depends on activities of the lymphocytes and is a specific resistance. It usually develops after exposure to environmental hazards.

Adaptive

Give examples of innate defense.

Surface barriers - skin, mucous membranes

Internal defenses - phagocytes, NK cells, inflammation, fever, antimicrobial proteins

Give examples of adaptive defenses.

Humoral immunity - B Cells

Cellular immunity - T cells

What are the seven major categories of innate defense?

1. Physical barriers

2. Phagocytes

3. Immunological surveillance

4. Interferons

5. Complement

6. Inflammatory response

7. Fever

Immunological surveillance constantly monitors normal tissues and is carried out by what cells?

NK cells

What are interferons?

Chemical messengers that trigger production of antiviral proteins in normal cells

Antiviral proteins don't kill viruses but rather do what?

Block replication in the cell

What is the complement system?

a circulating system of proteins that assists antibodies in destruction of pathogens

What is an inflammatory response?

Localized, tissue-level response that tends to limit spread of injury or infection.

A fever does what three things?

increases body metabolism

accelerates defenses

inhibits some viruses and bacteria

What are the nonspecific physical barriers of defense?

outer layer of skin

hair

epithelial layers of internal passageways

secretions that flush away materials - sweat glands, mucus, urine

secretions that kill/inhibits microorganisms - enzymes, antibodies, stomach acid

In what ways do activated macrophages respond to pathogens?

Engulf pathogen and destroy it with lysosomal enzymes

Destroy pathogen by releasing toxic chemicals into interstitial fluid

All macrophages have what two things in common?

Move through capillary walls (emigration)

Are attracted or repelled by chemicals in surrounding fluids (chemotaxis)

Phagocytosis begins when:

phagocytes attaches to target and surrounds it with a vesicle

Activated NK Cells do what 4 things?

1. ID and attach to abnormal cells (nonselective)

2. Golgi apparatus in NK cell forms perforin vesicles

3. Vesicles release proteins called perforins

4. Perforins lyse abnormal plasma membrane

(Also attack cancer cells and cells infected with viruses)

Cancer cells contain what?

tumor-specific antigens

What is the term for when a cancer cell is able to avoid NK cells?

Immunological escape

Cells infected with viruses present __________ ______ on plasma membranes.

abnormal proteins

The abnormal proteins on the infected cells allow the NK cells to do what?

Identify and destroy them

These are proteins (cytokines) released by activated lymphocytes and macrophages.

Interferons

These are chemical messengers released by tissue cells to coordinate local activities and to act as hormones to affect the whole body.

Cytokines

Complements work together in __________.

Cascades

What are the two pathways that activate the complement system?

1. Classical pathways

2. Alternative pathways

How does the classical pathway of complement activation work?

Classical is the fast way

1.C1 binds to - antibody molecule attached to antigen

2. Bound to protein, acts as enzyme - catalyzes chain reaction

How does the alternative pathway of complement activation work?

Alternative activation is the slow way

Exposed to antigen

Factor P, B, D

Interact in plasma

Both the alternative and classical pathways of complement end with what?

Conversion of inactive complement protein C3 to active form C3b

What are the effects of complement activation?

Pore formation - Destruction of target plasma membranes

Enhancement of phagocytosis by opsonization - complements working with antibodies (opsonins)

Histamine release - increases the degree of local inflammation and blood flow

What triggers inflammation?

any stimulus that kills cells or injures tissue

What are the cardinal signs and symptoms of inflammation?

Swelling

Redness

Heat

Pain

What are the products of inflammation?

Necrosis - local tissue destruction in area of injury

Pus - mixture of debris and necrotic tissue

Abscess - pus accumulated in an enclosed space

This is any material that causes the hypothalamus to raise the body temperature.

Pyrogens

This is a special pyrogen that is released by active macrophages.

Endogenous pyrogens or interleukin-1 (IL-1)

In specific defense the T cells do what?

Provide cell-mediated immunity

Defend against abnormal cells and pathogens inside cells

In specific defense the B cells do what?

Provide antibody-mediated immunity

Defend against antigens and pathogens in body fluids

What are the 4 forms of immunity?

Innate

Adaptive

Active

Passive

This form of immunity is present at birth.

Innate

This form of immunity is acquired after birth.

Adaptive

This form of immunity has antibodies that develop after exposure to antigens.

Active

This form of immunity has antibodies that are transferred from another source.

Passive

This kind of active immunity is acquired through environmental exposure to pathogens.

Naturally acquired Active immunity

This kind of active immunity is acquired through vaccines containing pathogens.

Artificially induced active immunity

This kind of passive immunity contains antibodies acquired from the mother.

Naturally acquired passive immunity

This kind of passive immunity is acquired by an injection of antibodies.

Artificially induced passive immunity

What are the 4 properties of immunity?

1. Specificity

2. Versatility

3. Memory

4. Tolerance

In this property of immunity, each T or B cell responds only to a specific antigen and ignores all others.

Specificity

In this property of immunity, the body produces many types of lymphocytes. Each fights a different type of antigen and active lymphocytes clone themselves to fight specific antigen.

Versatility

In this property of immunity, some active lymphocytes stay in circulation and provide immunity against new exposure.

Memory

In this property of immunity, the immune system ignores "normal" antigens.

Tolerance

There are two main divisions of in the immune response, those of the T cells and those of the B cells. what are they?

Cell-mediated immunity (T cells)

Antibody-mediated immunity (B cells)

What are the 4 major types of T cells?

1. Cytotoxic (T8) cells

2. Memory T cells

3. Helper T cells (T4)

4. Suppressor T cells

This kind of T cell attacks cells infected by viruses and is responsible for cell-mediated immunity.

Cytotoxic T cells

This kind of T cell clones themselves in response to "remembered" antigen.

Memory T cells

This kind of T cell stimulates the function of T cells and B cells.

Helper T cells

This kind of T cells inhibit function of T cells and B cells.

Suppressor T cells

T cells only recognize antigens that are bound to ______________ in plasma membranes.

glycoproteins

These are the membrane glycoproteins that bind to antigens and are genetically coded. They differ among individuals.

MCH Proteins

There are two classes of MHC Proteins, Class I and Class II. Which class is found in the membranes of all nucleated cells?

Class I

There are two classes of MHC Proteins, Class I and Class II. Which class is found in the membranes of antigen-presenting cells (APCs) and lymphocytes?

Class II

This class of proteins pick up small peptides in cells and carry them to the surface.

Class I MHC Proteins

Class I MHC Proteins: T cells ignore what?

Normal peptides

Abnormal peptides or viral proteins activate ___ _______ to destroy cells.

T cells

In Class II MHC Proteins, antigenic fragments come from what?

Antigenic processing of pathogens

Antigenic fragments bind to what?

Class II proteins

Antigenic fragments are inserted into plasma membranes to stimulate what?

T cells

Antigen-presenting cells are responsible for what?

Activating T cells against foreign cells and proteins

What are the three kinds of phagocytic APC's and where are they found?

1. Free and fixed - in connective tissue

2. Kupffer Cells - in the liver

3. Microglia - in the CNS

What are the two kinds of non-phagocytic APCs and where are they found?

1. Langerhans - in the skin

2. Dendritic - lymph nodes and spleen

What cell does antigen recognition recognizes?

T cells

These are known as cluster of differentiation markers.

CD markers

CD markers are located where?

In T cell membranes

CD3 receptor complexs are found where?

in all T cells

What are two important CD markers?

1. CD8 - found on cytotoxic T cells and suppressor T cells

2. CD4 - found on helper T cells

CD8 and CD4 bind to what receptor complex?

CD3

For T cell to be activated, it must be costimulated. What does this mean?

Binding to stimulating cell at second site which confirms the first signal

What three steps does a cytotoxic T cell go through?

1. Release perforin

2. secrete poisonous lymphotoxin

3. Activate genes in target cell

This kind of T cell secretes suppression factors, inhibits responses of T and B cells, act after initial immune response, and limit immune reaction to a single stimulus.

Suppressor T cells

What are the 4 functious of Cytokines?

1. Stimulate T cell divisions

2. Attract and stimulate macrophages

3. Attract and stimulate activity of cytotoxic T cells

4. Promote activation of B cells

These cells are responsible for antibody-mediated immunity,and attack antigens by producing specific antibodies.

B cells

During B cell sensitization, the antigens are:

Taken into the B cell

Processed

Reappear on surface, bound to class II MHC protein

Sensitized B cells are prepared for activation but needs _____ ____ cell activated by the same antigen.

T cell

Activated B cell divides into:

Plasma cells

Memory B cells

These cells synthesize and secrete antibodies into interstitial fluid.

Plasma Cells

These cells, like memory T cells, remain in reserve to respond to the next infection.

Memory B cells

An antibody structure is made of two parallel pairs of polypeptide chains. what is the difference between the two chains?

One is heavy and one is light

An antibody structure is made of two parallel pairs of polypeptide chains. what is the similarity between the two chains?

each chain contains constant segments and variable segments

What are the 5 heavy-chain constant segments?

1. IgG

2. IgE

3. IgD

4. IgM

5. IgA

The variable segments of light and heavy chains determine __________ of antibody molecule.

Specificty

A complete antigen has two _________ _________ sites.

Antigenic determinate sites

These must attach to a carrier molecule to act as a complete antigen.

Hapten

What are the dangers of haptens?

antibodies produced will attack both hapten and carrier molecule

if carrier is "normal": antibody attacks normal cells

What are the seven functions of antigen-antibody complexes?

1. neutralization of antigen binding sites

2. precipitation and agglutination

3. activation of complement

4. attraction of phagocytes

5. opsonization increasing phagocyte efficiency

6. stimulation of inflammation

7. prevention of bacterial and viral adhesion

Primary and secondary responses to antigen exposure occur in both _____________ and ________ immunity.

cell-mediated

antibody-mediated

The first exposure to an antigen produces initial what?

primary response

The second exposure triggers what?

secondary response that is more extensive and prolonged and the memory cells are already primed

What are 4 characteristics of the primary response?

takes time to develop

antigens activated B cells

plasma cells differentiate

Antibody titer level slowly rises

Is the primary or secondary response the peak response?

Primary

How long will the primary response take to develop?

up to two weeks

What is produced faster that IgG but is less effective?

IgM

The secondary response activates what kind of cells?

Memory B cells

What are the effects of memory B cell activation on IgG?

rises very high and quickly

can remain elevated for extend time

What are the effects of memory B cell activation on IgM?

Production is also quicker

slightly extended

What is the combined response to bacterial infection?

1. Neutrophils and NK cells begin killing bacteria

2. Cytokines draw phagocytes to area

3. Antigen presentation activates: helper T cells, Cytotoxic T cells

4. B cells activate and differentiate

5. Plasma cells increase antibody levels

What is the difference in a viral response vs. a bacterial response?

Cytotoxic T cells and NK cells are activated by contact with the virus-infected cells

Before birth, what antibody passes to the fetus through the placenta?

IgG

A mothers milk provides what kind of antibodies?

IgA