Lymphatic System and Body Defenses

terminal arteriole

1

What happens once the inflammatory process has begun?

1. Neutrophils, responding to a gradient of diffusing inflammatory chemicals, enter the blood from the bone marrow and roll along the blood vessel walls, following the "scent". 2. At the point where the chemical signal is the strongest, they flatten out and squeeze through the capillary walls, a process called diapedesis. 3. Still drawn by the gradient of inflammatory chemicals (positive chemotaxis), the neutrophils gather at the site of tissue injury, and within an hour, they are busily devouring any foreign material present.

Describe two sources of self-antigen that may trigger autoimmune diseases

1. New self-antigens appear- such "hidden" antigens are found in sperm cells, they're lens, and certain proteins in the thyroid gland. These may appear as a result of mutations that change the structure of self-proteins or as a result of alternations in self-protein by hapten attachment or by bacterial or viral damage 2. Foreign antigens resemble self-antigens- Antibodies produced during an infection caused by streptococcus bacteria (such as strep throat or scarlet fever) are known to cross-react with heart antigens, causing damage to both the heart muscle and its valves, as well as to the joints and kidneys. This age-old disease is called rheumatic fever.

Phagocytosis by a macrophage

1. Phagocyte adheres to pathogens 2. Phagocyte engulfs the particles, forming a phagosome. 3. Lysosome fuses with the phagocytic vesicle, forming a phagolysosome. 4. Lysosomal enzymes digest the pathogens or debris, leaving a residual body. 5. Exocytosis of the vesicle removes indigestible and residual material.

capillary bed

5

post capillary veinule

6

An individual receives a polio vaccine

Active Artificially

Immulogical memory is provided

Active Artificially or Natually

A little girl gets chicken pox

Active or Passive Naturally

Having a cornea transplant from an old Somaoan man

Allograft

Receiving a new kidney from your brother

Allograft

Tissue grafts take from a person other than an identical twin

Allografts

Macrophages capture and destroy harmful bacteria

Appendix

lymphoids are found in its wall

Appendix

tubelike offshoot of proximal large intestine (MALT- mucosa-associated lymphoid tissue)

Appendix

Describe how lymph nodes carry out their function.

As lymph is transported toward the heart, it is filtered through thousands of lymph nodes that cluster along the lymphatic vessels. Within the lymph nodes are macrophages, which engulf and destroy bacteria, viruses, and other foreign substances in the lymph before it is returned to the blood. Lymphocytes (WBC) respond to foreign substances in the lymphatic stream. Most lymph nodes are kidney-shaped and "buried" in the connective tissue that surrounds them.

Transplanting skin from your inner thigh to a burn on your face

Autograft

Tissue grafts transplanted form one site to another of the same person

Autografts

thoracic duct

B

Produces antibodies that are released into body fluids

B cell

Progeny are plasma cells

B cell

Name three potentially dangerous particles that may enter lymph capillaries. Explain how they are prevented from circulating throughout the body.

Cell debris, bacteria, and viruses enter the lymphatic capillaries easily, particularly in inflamed areas. Bacteria, viruses, and cancer cells that enter the lymphatics can then use them to travel throughout the body. This dilemma is partly resolved by the fact that white blood cells can also travel in lymph and lymph takes "detours" through the lymph nodes, where it is cleansed of debris and "examined" by cells of the immune system.

lymphatics

F

one danger of immunosuppressive drugs is hair loss

False

If transplants have not been rejected within 5 years, there is a 90% chance they will never be rejected

False 10 years

During what period of time of a human's life does immunocompetence develop?

Fetal Life

Kidney function is effected

Glomerulonephritis

Thyroid gland activity increases

Grave's disease

Is a dimer

IgA

Secretory antibody found in mucous membranes

IgA

Bound to surface of B cell

IgD

Is a monomer

IgD IgG IgE

Binds to mast cells and mediates allergic responses

IgE

Chief antibody released during secondary immune response

IgG

Crosses the placenta

IgG

Most abundant antibody in blood plasma

IgG

First antibody released during the primary immune response

IgM

Is a pentamer

IgM

Fixes complement

IgM IgG

Getting a new knee from a clone living on an island off the coast of South Carolina

Isograft

Tissue grafts donated by a genetically identical person, the only example being an identical twin

Isografts

What determines which antigen a particular T or B cell will be able to recognize?

It's genes

Describe the path lymph flows through the node. Explain how this path helps the node carry out its function.

Lymph enters the cortex side of a lymph node through afferent lymphatic vessels. It then flows through the lymph node and finally exits from the node at its indented region, the hilum, via efferent lymphatic vessels. Because there are fewer efferent vessels draining the node than afferent vessels feeding it, the flow of lymph through the node is very slow, kind of like sand flowing through an hour glass. This allows time for the lymphocytes and macrophages to perform their protective functions.

Name a second way the lymph is pumped through the lymphatics and back toward the blood.

Lymph is transported by the same mechanisms that aid return of venous blood-milking action of skeletal muscles and pressure changes in the thorax during breathing.

State the purpose of lymph nodes.

Lymph nodes help protect the body by removing foreign material such as bacteria and tumor cells from the lymphatic stream and by producing lymphocytes that function in the immune response.

Explain how the structure of the lymphatic allows fluid to enter the capillary and flow toward the heart.

Lymphatic capillaries are so permeable that they were once thought to be open at one end like a straw. The edges of the endothelial cells forming their walls loosely overlap one another, forming flap like minivalves that act as one-way swinging doors. The flaps, anchored by fine collagen fibers to surrounding structures, gape open when the fluid pressure is higher in the interstitial space, allowing fluid to enter the lymphatic capillary. When pressure is higher inside the lymphatic vessels, the endothelial cell flaps are forced together, preventing the lymph from leaking back out and forcing it along the vessel.

Acts as a sentinel to protect the upper respiratory and digestive tracts from the constant attacks of foreign matter entering those cavities

MALT

Impairs communication between nerves and skeletal muscles

Myasthenia gravis

Anaphylactic shock

Occurs when the allergen directly enters the blood and circulates rapidly through the body, as might happen with certain bee stings, spider bites, or an injection of a foreign substance (such as horse serum, penicillin, or other drugs that act as haptens) into susceptible individuals. Flood allergies (peanut or wheat allergies) may also trigger anaphlyaxis, and can be fatal.

A snake wrangler receives an injection of antivenom after he is bitten by a rattlesnake

Passive Artificially

Borrowed immunity

Passive Artificially

Antibodies migrate across the placenta to the fetus

Passive Naturally

Macrophages capture and digest harmful bacteria

Peyer's patches

found in the wall of the distal small intestine; MALT (mucosa-associated lymphoid tissue)

Peyer's patches

resemble tonsils

Peyer's patches

Explain how regulatory T cells are involved in the immune response.

Regulatory T cells release chemicals that suppress the activity of both T and B cells. They are vital for winding down and stopping the immune response after an antigen has been successfully inactivated or destroyed. This helps prevent uncontrolled or unnecessary immune system activity. Most of the T cells enlisted to fight in a particular immune response are dead within a few days. A few members of each clones are long-lived memory cells that remain behind to provide the immunological memory for each antigen encountered and enable the body to respond quickly to subsequent invasions.

Joints destroyed

Rheumatoid arthritis (RA)

Name a third way the lymph is pumped through the lymphatics and back toward the blood.

Smooth muscle in walls of larger lymphatics contracts rhythmically, helping to "pump" the lymph along.

Systemic disease that occurs mainly in young women and particulary affects the kidneys, heart, lung, and skin

Systemic lupus erythematosus (SLE)

Bears a cell surface receptor capable of recognizing a specific antigen

T and B cell

Forms clones upon simulation

T and B cell

Progeny include memory cells

T and B cells

Accounts for most of the lymphocytes in circulation

T cell

Is responsible for the direct attack of foreign and virus infected cells

T cell

Originates from hemocytoblasts in the bone marrow

T cell

Progeny include suppressors, helpers and killers

T cell

What is the result of complement fixation?

The formation of membrane attack complexes (MAC) that produce holes, or pores, in the foreign cell's surface. These pores allow water to rush into the cell, causing it to burst, or lyse.

What happens when cells are damaged?

The inflammatory response process begins with a chemical "alarm". When cells are damaged, they release inflammatory chemicals, including histamine and kinins that (1) cause blood vessels in the area to dilate, (2) make capillaries leaky, and (3) attract phagocytes and white blood cells to the area. (This third phenomenon is called positive chemotaxis because the cells are moving toward a high concentration of signaling molecules.)

Name one way the lymph is pumped through the lymphatics and back toward the blood.

The lymphatic vessels are thin walled, and larger ones have valves. The lymphatic system is a low-pressure pumpless system.

Acute hypersensitivity

This starts with the release of a flood of histamine when IgE antibodies bind to mast cells. Histamine causes small blood vessels in the area to become dilated and leaky and is largely to blame for the best-recognized symptoms of allergy: runny nose, watery eyes, and itchy reddened skin (hives)

Cell membrane antigens must be at least a 75% match for grafts to be attempted

True

It is important that he blood types of donor and recipient match

True

Pancreas cells attacked

Type 1 diabetes mellitus

Getting a heart valve from a pig

Xenograft

Tissue grafts harvested from a different animal species, such as a porcine (pig) heart valve transplanted into a human

Xenografts

When your B cells encounter antigens and produce antibodies against them

active immunity

Dangers (invaders): bacteria, viruses, transplanted organs or grafts, and cancer

adaptive defense mechanisms

Specificity: specific defense system

adaptive defense mechanisms

Speed of response: slower than innate

adaptive defense mechanisms

lymphocytes, antibodies, and macrophages

adaptive defense mechanisms

Lymph enters the convex side of a lymph node through _____________ _______________ ____________.

afferent lymphatic vessels

Antibodies can inactivate antigens in various ways depending on the nature of the ____________. ________________ is the chief ammunition used against cellular antigens such as bacteria and miss matched red blood cells. The binding of antibodies to sites on bacterial exotoxins or viruses that can cause cell injury called ____________________. The cross linking of cellular antigens into large lattices by antibodies is called ___________________. Ig__, with 10 antigen binding sites, is particularly efficient in this mechanism. When molecules are cross-linked into lattices by antibodies, the mechanism is more properly called _________________. In virtually all these cases, the protective mechanism mounted by the antibodies serves to disarm/immobilize the antigen until they can be disposed of by ________________.

antigen; Complement; neutralization; agglutination; M; precipitation; phagycytes

Immunity is the resistance to disease resulting from the presence of foreign substances or ____________ in the body. When this resistance is provided by antibodies released to body fluids, the immunity is called _____________ _____________. When living cells provided the protection, the immunity is referred to as ________________ __________________. The major actors in the immune response are two populations of lymphocytes: __ ______ and __ _______. Phagocytotic cells that act as accessory cells in the immune response are the ___________________. Because pathogens are likely to use both __________ and _________ as a means of getting around the body, __________ ___________ and other lymphatic tissues (which house the immune cells) are in an excellent position to detect their presence.

antigens; humoral immunity; cellular immunity; B cells; T cells; macrophages; blood; lymph; lymph nodes

defensive proteins that assist the innate defenses by attacking microbes directly or by preventing their reproduction

antimicrobial proteins

What signifies that a lymphocyte has become immunocompetent?

appearance of antigen-specific receptors on membrane of lymphocytes

Active immunity is _____________ ______________ when we receive vaccines

artificially acquired

propel debris-laden mucus away from lower respiratory passages

cilia

group of at least 20 plasma proteins that lyses microorganisms, enhances phagocytosis by opsonization, and intensifies inflammatory response

complement

Occurs when complement proteins bind to certain sugars or proteins (such as antibodies) on the foreign cell's surface

complement fixation

The outer part of the node, its __________, contains collections of lymphocytes called _______________, many of which have dark-staining centers called __________________ ____________.

cortex; follicles; germinal centers

Immunodeficiency

disease resulting from the deficient production or function of immune cells or certain molecules required for normal immunity

An abnormal accumulation of fluid in body parts or tissues; causes swelling

edema

Whole animal grafts like baboon hears are common in children

false

Allografts are most often taken from living donors

false (dead)

Most grafts need minimal blood supply to be successful

false (only cornea)

systemic response triggered by pyrogens; high body temperature inhibits multiplication of bacteria and enhances body repair processes; body temperature is regulated by hypothalamus, referred to as the "body's thermostat"

fever

contains concentrated hydrochloric acid and protein-digesting enzymes that destroy pathogens in stomach

gastric juice

Circle the term that does not belong with the others. Protein complete antigen nucleic acid hapten

hapten

Lymph exits from the node at its indented region, the ____________, via ________________ _______________ ______________.

hilum; efferent lymphatic vessels

Antigens are substances capable of mobilizing the _______________ _________________. Of all the foreign molecules that act as complete antigens, _______________ are the most potent. Tissues in our bodies are recognized as belonging to our body by ________________________ on their surface. They do not trigger an ________________ _________________ in our body but may do so in others. Small molecules are not usually antigenic, but when they bind to self-cell surface proteins they may act as ______________, and then the complex is recognized as foreign or _______________.

immune system; proteins; self-antigens; immune response; haptens; nonself

Adaptive defense- It is systemic

immunity is not restricted to the initial infection site

prevents spread of injurious agents to adjacent tissues, disposes of pathogens and dead tissue cells, and promotes tissue repair; releases chemical mediators that attract phagocytes (and immune cells) to the area

inflammatory response

1st line of defense: skin, mucous membranes, and secretion of skin and mucous membranes

innate defense mechanisms

2nd line of defense: phagocytic cells, natural killer cells, antimicrobial proteins, inflammatory response, fever

innate defense mechanisms

Dangerous (invaders): foreign substances

innate defense mechanisms

immune system you are born with

innate defense mechanisms

specificity: nonspecific defense system

innate defense mechanisms

speed of response: immediate

innate defense mechanisms

The ___________ and __________________ ________________ _____________________ make up the immune system.

innate; adaptive defense mechanisms

AIDS (acquired immunodeficiency syndrome)

interferes with the activity of helper T cells. It is characterized by severe weight loss, night sweats, swollen lymph nodes, and increasingly frequent infections. It is caused by a virus transmitted in blood, breast milk, semen, and vaginal secretion.

proteins released by virus-infected cells that protect uninfected tissue cells from viral takeover; mobilize immune system

interferons

Adaptive defense- It is antigen specific

it recognizes and acts against particular pathogens or foreign substances

Adaptive defense- It has "memory"

it recognizes and mounts even stronger attacks on previously encountered pathogens

provides resistance against acids, alkalis, and bacterial enzymes

keratin

Circle the term that does not belong with the others. Lymph nodes liver spleen thymus bone marrow

liver

The microscopic _________ ______________________ weave between the tissue cells and blood capillaries in the loose connective tissues of the body and absorb the leaked fluid.

lymph capillaries

Lymph is transported from the lymph capillaries through successively larger lymphatic vessels, referred to as _______________ _______________ ______________, until it is finally returned to the venous system through two large ducts in the thoracic region.

lymphatic collecting vessels

The function of the _____________ _______________ is to form an elaborate drainage system that picks up this excess interstitial fluid, now called _________, and returns it to the blood.

lymphatic vessels; lymph

The two independent parts of the lymphatic system are _______________ and _____________________.

lymphatic vessels; lymphoid tissues and organs

The lymphatic vessels, also called ___________, form a one-way system, and lymph flows only toward the heart.

lymphatics

Collections of ___________________ are also strategically located in the lymph nodes and respond to foreign substances in the lymphatic stream.

lymphocytes

Circle the term that does not belong with the others. Antibodies gamma globulin lymphokines immunoglobins

lymphokines

Within the lymph nodes are _____________________, which engulf and destroy bacteria, viruses, and other foreign substances in the lymph before it is returned to the blood.

macrophages

Delayed hypersensitivity

mediated mainly by a special subgroup of helper T cells, cytotoxic T cells, and macrophages, take much longer to appear (1 to 3 days) than any of the acute reaction produced by antibodies. The chemicals mediating these reactions are cytokines released by the activated T cells. Antihistamine drugs are not helpful against the delayed types of allergies. Costicosteroid drugs are used to provide relief.

Phagocytic macrophages are located in the central _____________ of the lymph node

medulla

B cell clone members that do not become plasm cells become long-lived ______________ _______ capable of responding to the same antigen if they "see" it again. Memory cells are responsible for the _________________ __________. These later immune responses, called ________________ _____________ ______________, are produced much faster, are more prolonged, and are more effective than the events of the primary response because all the preparations for this attack have been made.

memory cells; immunological memory; secondary humoral responses

traps microorganism in respiratory and digestive tracts

mucus

Myelin sheaths degenerate

multiple sclerosis (MS)

promote cell lysis by direct cell attack against virus-infected or cancerous body cells; do not depend on specific antigen recognition

natural killer cells

Active immunity is ______________ _______________ during bacterial and viral infections, during which we may develop the signs and symptoms of the disease and suffer a little (or a lot)

naturally acquired

Antibodies are obtained from the serum of an immune human or animal donor

passive immunity

engulf and destroy pathogens that breach surface membrane barriers

phagocytes

mixture of dead or dying neutrophils, broken-down tissue cells, and living and dead pathogens

pus

The ________ _______________ _______ drains lymph from the right arm and the right side of the head and thorax.

right lymphatic duct

During development of immunocompetence, the ability to tolerate ___________________________ must also occur if the immune system is to function normally.

self-tolerance

Located on the left side of the abdominal cavity; beneath the diaphragm, that curls around the anterolateral aspect of the stomach; around the left side of the stomach

spleen

soft organ

spleen

stores platelets and acts as a blood reservoir; filters and cleanses blood of bacteria, viruses, and other debris; provides a site for lymphocyte proliferation and immune surveillance; destroys worn-out red blood cells and returns some of their break down products to the liver

spleen

What triggers the process of clonal selection in a T or B cell?

the binding to the antigen

SCID (severe combined immunodeficiency)

the most devastating congenital condition in which there is a marked deficit of both B and T cells. Because T cells are absolutely required for normal operations of both arms of the adaptive response, afflicted children have essentially no protection against pathogens of any type. Minor infections easily shrugged off by most children are lethal to those with SCID. Bone marrow transplants and umbilical cord blood, which provide normal lymphocyte stem cells, have helped some SCID victims. Without treatment, the only hope for survival is living behind protective barriers (plastic "bubble") that keeps out all infectious agents

The large _________ _______ receives lymph from the rest of the body.

thoracic duct

anterior mediastinum overlying the heart; upper thorax, posterior to sternum

thymus

fibrous connective tissue; most active during youth

thymus

produces thymosin and others that appear to be essential for normal development of a special group of WBCs (T lymphocytes) and the immune response

thymus

pharyngeal region; part of MALT (mucosa-associated lymphoid tissue)

tonsils

small masses of lymphoid tissue deep to the mucosa surrounding the pharynx (throat)

tonsils

trap and remove bacteria or other foreign pathogens entering the throat, sometimes they become congested with bacteria and become red, swollen, and sore, a condition called tonsillitis

tonsils

autoimmune disease

when a person's own immune system produces a disorder