What are the 3 components of the lymphatic system?

1. lymphatic vessels, which contain a fluid called lymph

2. lymphatic organs, which include the lymph nodes, tonsils, spleen, and the thymus gland

3. lymphocytes, which include B cells and T cells.

What are the 2 major functions of the lymphatic system?

1. It drains the tissues of excess interstitial fluid.

2. It participates in immunity.

If there is too much H2O in the interstitium, the excess interstitial fluid drains into a nearby ____________.

lymphatic vessel (usually a lymphatic capillary)

If excess interstitial fluid were to remain in the interstitium, what happens?

The tissues would swell (edema), which causes tissue damage.

Once inside of a lymphatic capillary, what is interstitial fluid called?

Lymph

What is lymph?

Excess interstitial fluid found within the lymphatic vessels of the body.

What eventually happens with the excess interstitial fluid?

It will make it back to the blood because lymphatic vessels ultimately merge with veins.

What will happen to any pathogens (viruses, bacteria, etc.) that happen to be in the interstitium trying to invade body cells?

They will be swept into the lymphatic capillaries as a component of lymph.

Define immunity.

Resistance to disease

What cells function in immunity?

leukocytes (white blood cells)

True or False: Because of its role in immunity, parts of the lymphatic system can also function as the immune system.

True

The lymphatic system begins with the ____________, which are the smallest lymphatic vessels.

lymphatic capillaries

What does a lymphatic capillary consists of?

endothelial cells

How does a lymphatic capillary differ from a blood capillary? What is important about this?

1. It lacks a basement membrane.

2. The endothelial cells of a lymphatic capillary overlap

- This arrangement allows for unidirectional flow of fluid into the lymphatic capillary

1. As excess interstitial fluid approaches a lymphatic capillary, the __________ spread apart, forming large spaces between each other.

2. These spaces are _______ than the pores in a regular blood capillary and allow small molecules (like H2O) and large substances (such as proteins, viruses, bacterial cells, cancer cells, and debris) to move from the interstitium into the lumen of the lymphatic capillary. 

1. endothelial cells

2. larger

True or False: A lymphatic capillary is far less permeable than a blood capillary.

False.

Lymphatic capillaries converge to form larger lymphatic vessels; a larger lymphatic vessel resembles a ____ in structure, but has a ______ wall and more valves.

- vein

- thinner

Pathway of Lymph Flow Through the Lymphatic Vessels.

1. Excess interstitial fluid (and any dissolved pathogens and debris) flows from the interstitium into the ________, forming lymph.

2. The lymph then moves into larger ___________. As these* course through the body, they give rise to ________, where lymph is filtered of any pathogens and debris.

1. lymphatic capillaries

2. lymphatic vessels; lymph nodes

Pathway of Lymph Flow Through the Lymphatic Vessels.

3. Lymph eventually flows into the largest lymphatic vessels: the ___________ and the ____________.

4. Finally, lymph moves from these* into the _______________, respectively.

3. right lymphatic duct; thoracic (left lymphatic) duct

4. right and left subclavian veins

What are the 4 lymphatic organs?

1. lymph nodes

2. tonsils

3. spleen

4. thymus gland

Small, bean-shaped masses that are located between lymphatic vessels

lymph nodes

Where are single lymph nodes found?

throughout the body

1. Lymph nodes can also exist in groups; this is especially the case with the lymph nodes located where?

2. What are these lymph node groups called?

1. the neck, armpit, and groin

2. These lymph nodes are called cervical nodes, axillary nodes, and inguinal nodes, respectively.

Within a lymph node is _______________. What does this consist of?

- reticular connective tissue

- consists of reticular fibers, macrophages, and lymphocytes

Thin collagen fibers that interact together to form a net-like association

reticular fibers

Both B cells and T cells are part of what cell family?

lymphocytes

What is the function of lymph nodes?

to filter the lymph of foreign substances (pathogens and debris, etc.).

1. ____________ bring lymph to lymph nodes.

2. As lymph travels through each lymph node, any foreign substances in the lymph are trapped by the ____________, which then allows the ________ and ________ to destroy them (like a spider that traps and then kills a fly in its web).

1. Lymphatic vessels

2. net-like reticular fibers; macrophages; lymphocytes

Located in the pharynx (throat) and the oral cavity

tonsils

What are the 3 types of tonsils?

1. pharyngeal tonsils

2. palatine tonsils

3. lingual tonsils

- unpaired

- also called the adenoid

- located in wall of the nasopharynx

pharyngeal tonsils

- paired

- located in the posterior end of the oral cavity

- these* are most susceptible to infection and may have to be removed (tonsillectomy).

palatine tonsils

- paired

- located at the base of the tongue

lingual tonsils

The tonsils consist of reticular connective tissue containing ___________, ___________, and ___________.

- reticular fibers, macrophages, and lymphocytes

What is the function of the tonsils?

They trap and destroy any pathogens that enter the pharynx and oral cavity from inhaled air or from ingested food and beverages.

Close inspection of the external structure of the tonsils reveals that the tonsils contain ___________ that form valleys called crypts.

invaginations (folds)

1. As pathogens in air, food, or liquid interact with the tonsils, the pathogens become trapped in the _______.

2. By chance, the pathogens then move deeper into the _______________ within the tonsils, where the macrophages and lymphocytes destroy them.

1. crypts

2. reticular connective tissue

- the largest lymphatic organ

- located on the left side of the body between the diaphragm and the stomach

spleen

The spleen consists of reticular connective tissue that is organized into regions called ________ and ________

white pulp and red pulp

1. In addition, the spleen is heavily vascularized: the __________  provides blood to the spleen, while the __________ drains it.

2. Since the spleen is so heavily vascularized, trauma to the spleen can cause ___________________.

3. If this happens, the spleen must be removed (________) to stop the bleeding.

1. splenic artery; splenic vein

2. severe bleeding and even death

3. splenectomy

The spleen is involved in 2 major functions. What are they?

1. Filters the blood of pathogens

2. Destroys worn out blood cells

The spleen filtering blood out of pathogens.

1. The _________ brings blood to the spleen.

2. From this*, blood eventually moves into the ____________ that forms the white pulp and the red pulp.

1. splenic artery

2. reticular connective tissue

The spleen filtering blood out of pathogens.

3. As blood moves through the white pulp and red pulp, _____________________ remove and destroy any pathogens that get caught in the reticular fibers.

4. The blood then moves from the white pulp and red pulp into the _________, which takes the filtered blood away from the spleen.

3. lymphocytes and macrophages

4. splenic vein

–Hence, the filtering function of the spleen is similar to that of the lymph nodes; the only difference is that the spleen filters blood, while the lymph nodes filter lymph.

As blood is filtered in the spleen, the __________ can remove and destroy any worn out blood cells via __________.

- macrophages

- phagocytosis

- bi-lobed gland that partially covers the superior portion of the heart

thymus gland

- The size of the thymus gland changes with age: it is largest during infancy and childhood and gradually gets smaller as we age.

- promotes the maturation of T cells

- contains T lymphocytes (T cells)

thymus

Function of thymus gland.

1. __________ cells are initially produced in the red bone marrow.

2. Afterwards, these* are released into the blood and then migrate to the __________.

1. Immature T

2. thymus gland

Function of thymus gland.

3. The thymus gland produces hormones called _________ that mature the T cells.

4. The mature T cells then migrate back into the blood. Some T cells patrol the blood for pathogens, while others move into ______________ to fight pathogens there.

3. thymosins

4. lymphatic organs (like the lymph nodes)

Note that B cells are produced and matured in the __________ and, therefore, do not have to migrate to the thymus gland.

red bone marrow

What are the two major types of immunity?

1. nonspecific

2. specific

The ability to protect the body from any foreign substance in a general way

nonspecific immunity

Recall that there are several types of white blood cells that are involved in nonspecific immunity. What are they? (4 total)

1. neutrophils

2. monocytes/macrophages

3. eosinophils

4. basophils

The ability to protect the body from any foreign substance in a way that involves specificity and memory

specific immunity

How is specific immunity achieved?

Through the activities of B lymphocytes and T lymphocytes (also called B cells and T cells, respectively).

What is it when specific immunity targets a specific pathogen?

specificity (example: E. coli vs. the influenza virus).

- The more specific the immune response is, the easier it is to kill the invading pathogen

____________ is more general and, therefore, can target any type of pathogen (any type of bacterium or virus, etc.).

Nonspecific immunity

- A major disadvantage to this generalized approach is that it is harder to kill a pathogen without being able to specifically target it

1. Specific immune responses involve _______, while this* is not associated with nonspecific immunity.

2. A person often becomes ill upon the _____ exposure to a particular pathogen.

1. memory

2. first (This is because it usually takes time for nonspecific immunity and for specific immunity to become effective.)

An antigen is any substance that the body recognizes as being __________ and is therefore __________ (promotes a specific immune response).

- foreign (nonself)

- immunogenic

True or False: Most antigens are foreign proteins.

True

What are the 2 different components of pathogens?

1. the capsid (protein coat) or glycoproteins of a virus

2. the proteins in the cell wall and flagellum of a bacterial cell

What are some examples of antigens?

- pollen (plant sperm)

- certain food proteins (peanuts are immunogenic in many people)

- foreign human cells (A or B antigens in the cell membranes of RBC)

Promotes a specific immune response.

immunogenic

The _______ of lipids, nucleic acids, carbohydrates, and proteins are the same from person to person and, consequently, are ____________ to other people.

- majority

- not immunogenic

There is a group of proteins called the _______________ that is unique from individual to individual and, consequently, causes an immune response when introduced into another person

major histocompatibility complex (MHC

- a special group of proteins found in the plasma membrane of nucleated cells

- unique from individual to individual (Exception: identical twins)

- serve as cellular “identity tags” or self-antigens

major histocompatibility complex (MHC)

True or False: Self-antigens are proteins that can belong to more than one person.

False

- Self-antigens are proteins that belong in one person and nobody else

This is the basis of tissue rejections during tissue or organ transplantation.

major histocompatibility complex

The MHC antigens in the cells of one of your close relatives are __________ to your own MHC antigens; therefore, a close relative ____ donate an organ to you without there being a severe immunogenic response in your body.

- very similar

- can 

RBCs are non-nucleated cells; consequently, they lack __________.

MHC proteins

- Nevertheless, RBCs do contain their own self-antigens: the antigens of the ABO blood group and those of the Rh blood group.

Production of B and T cells.

1. B cells and T cells are produced in ___________ from ____________ via the process of hematopoiesis.

- red bone marrow

- hemocytoblasts

Production of B and T cells.

2. Once they are produced, the B cells remain in the red bone marrow for a while to undergo maturation. T cells, however, do not mature in red bone marrow. Once they are produced, T cells migrate via the blood to the ______ gland to undergo maturation there with the help of thymosins (thymic hormones). During the maturation process, the B cells and the T cells become __________, which is the process by which B cells and T cells develop specific antigen-binding receptors in their plasma membranes. 

- thymus 

- immunocompetent

Production of B and T cells.

3. Once the maturation process has been completed, the immunocompetent B cells and T cells leave the red bone marrow and thymus gland, respectively, and migrate into the blood and into the _________________________. These lymphocytes continuously travel between the blood and lymphatic organs as they patrol these areas for antigens.

reticular connective tissue of lymphatic organs

There are millions of different types of B cells and millions of different types of T cells in the body; each of these cells contains a specific ______________ in its plasma membrane.

antigen-binding receptor

1. There are ______ copies of each of these different types of B cells and T cells before the initial exposure to antigens.

2. Such a small army consisting of only a few copies of each of these lymphocytes is not enough to fight a massive invasion of pathogens. As a solution to this problem, when a B cell or T cell binds to an antigen, it undergoes ____________.

1. only a few

2. clonal selection

- The process by which a B cell or T cell divides into a clone of cells that can bind to the same antigen

- Results in the production of more B cells or T cells (often thousands of them) that can be used to destroy an antigen

clonal selection

- In addition, the cells of the clone become differentiated.

- Although the differentiated cells of the clone bind to the same antigen, they function differently in the specific immune response that is about to occur

Formation of B Cell Clones.

1. An ______ invades the body.

2. The _______ on the appropriate B cell binds to this*.

1. antigen

2. receptor

Formation of B Cell Clones.

3. The B cell is then activated by _______ released from a helper T cell.

4. The B cell subsequently undergoes _________, resulting in the production of many plasma cells and memory B cells. Both of these cell types bind to the same antigen as the original B cell.

3. cytokines

4. clonal selection

Secrete antibodies into the blood or other body fluids

plasma cells

- also called an immunoglobulin (Ig) 

- a protein that binds to and subsequently destroys an antigen

antibody

- The antibodies secreted by the plasma cell are specific for the antigen that was recognized by the original B cell.

- Antibodies are found in many types of body fluids (blood , saliva, lymph, tears, mucus, breast milk, etc.)

- cells that remember the antigen that caused the original B cell to undergo clonal selection

- Should the same antigen invade the body again, these* immediately produce more plasma cells and more memory B cells that possess the same antigen specificity.

memory B cells

- Consequently, there is a rapid production of antibodies produced by the plasma cells, which results in the quick destruction of the pathogen.

- This response is so fast that the person typically does not exhibit any signs of being ill.

How long do memory B cells stay around in the body?

Decades!

There are four ways to acquire specific immunity. What are they?

1. active natural immunity

2. active artificial immunity

3. passive natural immunity

4. passive artificial immunity

- specific immunity (i.e. proliferation of B cells/antibodies or T cells) that a person develops due to natural exposure to an antigen (i.e. by chance)

- The person will typically develop signs of illness since there has not been a previous encounter with the antigen.

active natural immunity

- specific immunity that a person develops due to deliberate exposure to an antigen by a process called vaccination

-- In this process, a person receives a vaccine, which consists of an attenuated (weakened) pathogen.

active artificial immunity

- Since the pathogen is attenuated, it does not cause harm to the body but it is still immunogenic and will result in the production of either B cells/antibodies or T cells.

- Years after the vaccine has been administered, the person may need a booster shot to stimulate the number of memory cells in that person’s body just in case some of the previous memory cells that developed after the first vaccination.have dwindled in number.

- specific immunity that develops when antibodies are passed from mother to fetus through the placenta or from mother to infant via breast milk

passive natural immunity

- Neither a fetus nor an infant has a well-developed immune system and, therefore, both are susceptible to frequent pathogenic invasions.

- Passive natural immunity assures that the fetus and the infant are not totally helpless.

- These antibodies do not last forever; they are eventually broken down and the infant will have to rely on his or her own developing immune system to provide protection.

- specific immunity that a person develops by receiving serum

passive artificial immunity

Steps of Passive Artificial Immunity.

1. ________ an animal (like a horse or rabbit)

2. The animal’s immune system will respond to the vaccination by making __________ in its blood.

1. Vaccinate 

2. antibodies 

Steps of Passive Artificial Immunity.

3. Remove the ______ from the animal and then extract the ______, which contains the antibodies.

4. Inject the antibodies into the person that needs immunity to provide ____________.

3. blood; serum

4. immediate protection

_________________ is the preferred type of acquired immunity when there is an epidemic and, consequently, there is not enough time for a person to develop his or her own specific immune response.

Passive artificial immunity

the spread of a disease from one part of the body to another, can occur via lymphatic vessels

metastasis through lymphatic vessels

Occurs when there is trauma or damage to the abdomen -- severe blows to the inferior left chest or superior abdomen can fracture the protecting ribs. Such crushing injury may result in this*.

ruptured spleen

An infection or inflammation of the tonsils. Most often, it is caused by a virus, but it may also be caused the same bacteria that cause strep throat

tonsillitis

If pus cannot drain out of an inflamed region, the result is an _______ -- an excessive accumulation of pus in a confined space.

When superficial inflamed tissue sloughs off the surface of an organ or tissue, the resulting open sore is called an ______.

abscesses and ulcers

Usually, the immune system recognizes the proteins in the transplanted organ as foreign and mounts both cell-mediated and antibody-mediated immune responses against them. This is known as _____________.

_________ is done before any organ transplant.

graft rejection and tissue typing

Hybridomas are long-term sources of large quantities of pure, identical antibodies, called ___________ because they come from a single clone of identical cells.

monoclonal antibodies

The study of ways to use immune responses for detecting, monitoring, and treating cancer.

cancer immunology

A condition in which a person experiences a telltale assortment of infections due to the progressive destruction of immune system cells by the human immunodeficiency virus.

AIDS

1. The antigens that induce an allergic reaction

2. The most common and occur within a few minutes after a person sensitized to an allergen is re-exposed to it

3. May occur in a susceptible individual who has just received a triggering drug. Life-threatening emergency treated by injecting epinephrine

1. allergens

2. type I (anaphylactic) reactions

3. anaphylactic shock

- The immune system fails to display self-tolerance and attacks the person's own tissues. - Usually arise in early adulthood.

- Females suffer from this twice as often as males.

autoimmune diseases

- contagious disease caused by the Epstein-Barr virus (EBV)

- known as the "kissing disease"

infectious mononucleosis

- cancers of the lymphatic organs, especially the lymph nodes

- most have no known cause

lymphomas

- a chronic autoimmune, inflammatory disease that affects multiple body systems

- characterized by periods of active disease and remission

systemic lupus erythematosus

a transplant between genetically distinct individuals of the same species

allograft

a transplant in which one's own tissue is grafted to another part of the body

autograft

accumulation of lymph in lymphatic vessels, causing painless swelling of a limb

lymphedema

enlarged spleen

splenomegaly

a transplant between animals of different species (porcine or bovine to human)

xenograft