Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
194 Cards in this Set
- Front
- Back
|
What are the TWO BASIC functions of the lymphatic system and the lymphoid organs and tissues? |
- return fluids that have leaked from the blood vascular system back to the blood
- the organs provide the structural basis of the immune system |
|
|
What are the three parts that make up the lymphatic system?
|
- lymphatic vessels
- lymph - lymph nodes |
|
|
What are the lymphatic vessels and what purpose do they serve?
|
they are elaborate networks of drainage vessels that collect the excess protein-containing interstitial fluid and return it to the blood stream
|
|
|
Once interstitial fluid enters the lymphatic vessels, it is called...
|
lymph
|
|
|
What is housed in the lymphatic nodes?
|
phagocytic cells and lymphocytes
|
|
|
What is lymph fluid? What is found in lymph fluid?
|
it is interstitial fluid that has entered the lymphatic vessels; colorless fluid similar to blood plasma but low in protein (though, lymph draining from the small intestine is more milky, white due to the lipid absorption)
Composition varies from place to place but may contin macrophages, hormones, bacteria, viruses, cellular debris, and even small cancer cells; large number of lymphocytes |
|
|
What is the lymph system? What are the three types of lymph vessels (lymphatics)?
|
it is a one-way system that flows towards the heart, it transports fluid from tissue to blood circulation
lymphatic capillaries lymphatic collecting vessels lymphatic trunks and ducts |
|
|
Trace the flow of lymph from the tissues to the heart:
|
capillaries
collecting lymphatic vessels w/ valves lymph node lymph trunk lymph duct heart |
|
|
What the lymphatic capillaries and what are their characteristics?
|
- they are similar to blood capillaries but are extremely permeable
- take up debris, pathogens, and cancer cells - absent from bone, teeth, bone marrow, and the CNS |
|
|
To what do lymphatic capillaries owe their extreme permeability to?
|
- the endothelial cells forming their walls loosely overlap, forming easily opened, flaplike minivalves
- collagen filaments anchor the endothelial cells to surrounding structures so that any increase in interstitial fluid volume opens the minivalves, rather than causing the lymphatic capillaries to collapse |
|
|
What are lacteals?
|
special lymphatic capillaries that are present in intestinal mucosa, they absorb digested fat and delivery fatty lymph (chyle) to the blood
|
|
|
What is chyle?
|
fatty lymph that drains from the fingerlike villi of the intestinal mucosa by the use of lacteals
|
|
|
What are lymphatic collecting vessels? What are examples?
|
- similar to veins (have the same three tunics) but have thinner walls with more internal valves
- trunks and ducts |
|
|
How are lymphatic trunks formed? And what do they do?
|
lymphatic trunks are formed by the union of the largest collecting ducts
they drain the large areas of the body |
|
|
How is lymph moved up the body (lymph transport)? How is lymph propelled?
|
lacks an organ that acts as a pump - low pressure conduits
lymphatics in the skin travel along superficial veins, while the deep lymphatic vessels lymphatic vessels of the trunk and digestive viscera travel with the deep arteries lymph is propelled by: pulsations of arteries nearby and the contractions of smooth muscles in the walls of the lymphatics |
|
|
Lymph is delivered into one of two large ducts, which are? Where do they empty?
|
Right lymphatic duct: drains lymph from the right upper limb and the right side of the head and thorax
the thoracic duct: much larger then the right lymphatic duct receives lymph from the rest of the body; it arises from the cisterna chyli each empties lymph into venous circulation at the junction of the internal jugular and subclavian veins on its own side of the body, right about where the brachiocephalic veins are |
|
|
What are the lymphoid cells and what do they do? |
lymphocytes - main warriors of the immune system, arise in the red bone marrow. they mature into one of the two main varieties of lymphocytes:
- t cells: activated t cells manage the immune response and some of them directly attack and destroy infected cells - b cells: protect the body by producing plasma cells (daughter cells) that secrete antibodies into the blood (or other fluids) Macrophages: phagocytize foreign substances and help activate t cells, they are prominent in lymphatic tissue and are involved in specific immunity Dendritic cells: capture antigens and deliver them to lymph nodes, help activate t cells, look like a starfish, better at phagocytizing ("key guys") Reticular cells: "cheesecloth", skinny collagen fibers, produce stroma that supports other cells in lymphoid organs |
|
|
What is diffuse and follicle tissue?
|
lymphoid tissue
- diffuse lymphatic tissue is a loose arrangement of lymphoid cells and some reticular fibers and is found in virtually every body organ - lymphoid follicles/nodules are solid, spherical bodies consisting of tightly packed lymphoid cells and reticular fibers |
|
|
Why is lymphoid tissue an important component of the immune system?
|
- it houses and provides a proliferation site for lymphocytes
- furnishes an ideal surveillance vantage point for lymphocytes and macrophages |
|
|
What connective tissue dominates all the lymphoid organs?
|
reticular connective tissue dominates all the lymphoid organs except the thymus
|
|
|
What are the two basic functions of lymph nodes?
|
- filtration: machrophages in the nodes remove and destroy microorganisms and other debris that enter the lymph fro the loose connective tissues, preventing them from being delivered to the blood and spreading to other parts of the body
- immune system activation: lymph nodes and other lymphoid organs are strategically located sites where lymphocytes encunter antigens and are activated to mount an attack against them |
|
|
What is the structure of a lymph node?
|
- bean shaped, external fibrous capsule
- cortex: follicles with germinal centers, heavy with dividing B cells - medulla - medullary cords extend inward from the cortex and contain B cells, T cells, and plasma cells - lymph sinuses are present throughout the node and contain macrophages |
|
|
How does lymph circulate within a lymph node?
|
enters via afferent lymphatic vessels and exits the node at the hilus via efferent vessels
there are more afferent than efferent vessels which causes the lymph to stagnate allowing lymphocytes and macrophages time to carry out their functions |
|
|
What is the principal lymphoid organ of the body?
|
the lymph node
|
|
|
What is the largest lymphoid organ? |
spleen |
|
|
What artery and vein serve the spleen? |
the splenic artery and vein which enter and exit at the hilus |
|
|
What are the functions of the spleen? |
- site of lymphocyte proliferation and immune surveillance and response - cleanses the blood of aged cells, platelets, and debris - stores breakdown products of RBCs for reuse - stores blood platelets - site of fetal erythrocyte production - contains lymphocytes, macrophages, and huge numbers of RBCs |
|
|
What is the structure of the spleen? |
- surrounded by fibrous capsule and has trabeculae that extend inward - consists of red pulp and white pulp |
|
|
What is red pulp? |
- located in the spleen - where worn-out RBCs and bloodborne paths are destroyed, contains large number of erythrocytes and macrophages - consists of splenic cords reticular CT, and splenic sinusoids |
|
|
What is white pulp? |
- located in the spleen - where immune functions take place, mostly lymphocytes suspended on reticular fibers |
|
|
Can you survive a splenectomy? |
Yes, your immune system is just compromised, you would need antibiotics. |
|
|
What are the functions of the thymus? How does it differ from other lymphoid organs? |
- responsible for the maturity of T cells - differs from other lymphoid organs by: 1) no follicles due to no B cells, 2) doesn't directly fight antigens, 3) epithelial cells versus reticular fibers |
|
|
What is the structure of the thymus? |
- thymic lobes contain an outer cortex and inner medulla - cortex contains densely packed lymphocytes and scattered macrophages - the stroma of the thymus consists of star-shaped epithelial cells (not reticular fibers) |
|
|
What are the tonsils? |
- simplest lymphoid organs - form a ring of lymphatic tissue around the pharynx - epithelial tissue overlying tonsil masses invaginates forming tonsillar crypts, which trap and destroy bacteria and particulate matter |
|
|
What are the four types of tonsils? |
Palatine: located on either side at the posterior end of the oral cavity these are the largest and the ones most often infected
Lingual: collective term for a lumpy collection of lymphoid follicles at the base of the tongue
Pharyngeal: called "adenoids" if enlarged, posterior wall of the nasopharynx
Tubal: auditory tubes into the pharynx
ONLY THREE TYPES TRAP BACTERIA LOCATED IN ORO AND NASO PHARYNX |
|
|
What are Peyer's patches? Where are they located? What kind of lymphoid tissue are they? What do they do? |
- aggregate lymphoid nodules; large clusters of lymphoid follicles, structurally similar to the tonsils - located in the wall of the distal portion of the small intestine - diffuse tissue - keeps you from getting infection in the small intestine from bacteria traveling up from the large intestine; similar structures found in the appendix |
|
|
What function do both Peyer's Patches and the appendix perform? |
- generate "memory" lymphocytes - both in the ideal position to destroy bacteria before they can breach the intestinal wall and generate many "memory" lymphocytes for long-term immunity |
|
|
What is the appendix? What occurs there? |
- tubular offshoot of the first part of the large intestine and contains a high concentration of lymphoid follicles
- where bacteria flora is established before heading to the intestine |
|
|
What is MALT? What does it do? What does the term include? |
- general term for lymph tissue; mucosa-associated lymphatic tissue
- protects the digestive and respiratory systems from foreign matter
- includes: peyer's patches, tonsils, and the appendix (digestive tract), lymphoid nodules in the wall so the bronchi |
|
|
What is innate defense? What are its two lines of defense? |
- nonspecific - 1st line of defense - Two lines of defense: surface barriers (skin and mucus membranes) and internal defenses (antimicrobial proteins, phagocytes, natural killer cells, inflammation, and fever) |
|
|
What are surface barriers of innate defense? |
skin and mucus membranes |
|
|
What are internal defenses of innate defense? |
phagocytes natural killer cells inflammation antimicrobial proteins fever |
|
|
How does the structure of the surface barriers help with infection/disease control? |
- thickness of the skin - tight junctions between the cells in the intestine - vibrissiae (hairs in the nose) trap dust, insects, etc - cilia in the upper respiratory tract trap foreign objects |
|
|
How does the chemistry of the body help with infection/disease control? |
- acidity of the skin: secretions from sweat glands on skin are acidic, most bacteria do not like acidic environments - lipids and sebum in sebaceous glands: dermicidin pokes holes in bacteria - lysozymes: found in tears, stomach, blood poke holes in bacteria - mucin: enzyme dissolved in H2O and forms a thick mucous that traps bacteria then is swallowed - defensins: antibacterial protein prominent in mucous secretions, pokes holes in cell walls |
|
|
What cells are involved in innate/nonspecific immunity? |
Phagocytes (neutrophils and macrophages) and natural killers cells
there are also proteins and other chemicals |
|
|
What are macrophages? |
- derive from monocytes - are the chief phagocytic cells - come in free and fixed varieties |
|
|
What are free macrophages? |
wander throughout the tissue spaces in search of cellular debris or "foreign invaders" |
|
|
What are fixed macrophages? |
like stellate macrophages in the liver (Kupffer cells), are permanent residents of particular organs |
|
|
What are neutrophils? |
- phagocyte that are not as vicious as a macrophage but are the "first responders" - they use defensins - most abundant type of WBC - become phagocytic on encountering infectious material in the tissues |
|
|
What are natural killer cells? |
- ARE NOT PHAGOCYTIC - granulated lymphocyte - target cells that lack "self" cell-surface receptors - induce apoptosis in cancer cells and virus-infected cells - secrete potent chemicals that enhance the inflammatory response |
|
|
What are the five events of phagocytosis? |
1. Phagocyte adheres to pathogens or debris 2. Phagocyte forms pseudopods that eventually engulf the particles. 3. Lysosome fuses with the phagocytic vesicle. 4. Lysosomal enzymes digest the particles. 5. Exocytosis of the vesicle removes indigestible and residual material. |
|
|
What are lysosomes? |
organelles that originate from the Golgi apparatus and contain strong digestive enzymes - active in phagocytosis |
|
|
What is a phagosome? |
- vesicle formed as a result of phagocytosis - formed when pseudopods engulf the particles/pathogens/debris |
|
|
What are opsonins? What is opsonization? |
- opsonins are complement proteins or antibodies that provide "handles" to which phagocyte receptors can bind
- opsonization: "to make tasty", greatly accelerates phagocytosis of that pathogen; occurs when a pathogen is coated with opsonins |
|
|
What is the inflammatory response? |
triggered whenever body tissues are injured by physical trauma, intense heat, irritating chemicals, or infection by viruses, fungi, or bacteria |
|
|
What are the beneficial effects of inflammation? |
- prevents the spread of damaging agents to nearby tissues - disposes of cell debris and pathogens - alerts the adaptive immune system - sets the stage for repair |
|
|
What are the cardinal signs of acute inflammation? |
redness, heat, swelling, pain, and SOMETIMES loss of function/impairment |
|
|
Basic process of inflammation: |
injury = - release of inflammatory chemicals: increases vasodilation, swelling, some of the chemicals will attract neutrophils that migrate to the region - mobilization: leukocytosis (leukocytes are present in high numbers), margination (neutrophils cling to the walls of capillaries), diapedesis of neutrophils (leap out of BVs and into tissue), chemotaxis (inflammatory chemicals act as homing devices or chemotactic agents - allows neutrophils and other WBCs to migrate to site injury) |
|
|
What are antimicrobial proteins? |
they enhance our innate defenses by attacking microorganisms directly or by hindering their ability to reproduce
include interferons and complement |
|
|
What are interferons? |
small proteins secreted by a variety of body cells that are infected, they help to protect cells that have no yet been infected
they are antibacterial |
|
|
What are the functions of interferons? |
- anti-viral - reduce inflammation - activate macrophages and mobilize NK cells |
|
|
What are genetically engineered interferons for? |
antiviral agents against hepatitis and genital warts virus and multiple sclerosis |
|
|
What are the steps of the interferon process?
|
- virus enters a cell
- interferon genes switch on - the infected cell produces interferon molecules - interferon binding stimulates the uninfected cell to turn on genes for antiviral proteins - antiviral proteins block viral reproduction |
|
|
What are complements?
|
very powerful; a pathway that leads to the destruction (lysis) of foreign bodies
major mechanism for destroying foreign substances it is a nonspecific defense but it "complements" (enhances) the effectiveness of both innate and adaptive defenses |
|
|
What are the three complement pathways?
|
classical, lectin, and alternative
|
|
|
What is the classical pathway?
|
a type of complement pathway
activated by antibodies coating target cell - opsonization |
|
|
What is opsonization?
|
antibodies coat pathogen surfaces, which enhances phagocytosis
the coating makes the antigen more attractive to macrophages |
|
|
What is the lectin pathway?
|
type of complement pathway
activated by lectins binding to specific sugars on microorganism's surface involves MAC (membrane attack complex) |
|
|
What is MAC?
|
membrane attack complex
causes cell lysis by inducing massive intake of water in cell forms and stabilizes a hole in the membrane that allows a massiv influx of water, lysing the target cell |
|
|
What is the alternative pathway?
|
a type of complement pathway
activated spontaneously; lack of inhibitors on microorganism's surface allows process to proceed enhances inflammation |
|
|
How does a complement enhance inflammation?
|
stimulates histamine release, increases blood vessel permeability, attracts phagocytes by chemotaxis, etc.
|
|
|
What is fever?
|
an abnormally high body temperature
a systemic response to invading microorganisms an adaptive response |
|
|
What are pyrogens?
|
released by leukocytes and macrophages when they are exposed to foreign substances in the body
they act on the body's thermostat raising the body's temperature above normal |
|
|
What is fever good?
|
fever causes the liver and spleen to sequester iron and zinc, making them less available to support bacterial growth
fever increases the metabolic rate of tissue cells in general, speeding up repair processes |
|
|
What is specific/adaptive immunity
|
the body's built-in defensive system that stalks and eliminates with nearly equal precision almost any type of pathogen that intrudes into the body
|
|
|
What are two important things that the activity of the adaptive immune system amplifies?
|
the inflammatory response and most complement activation
|
|
|
What are the basic characteristics of humoral/antibody-mediated immunity?
|
- antibodies present in the body's "humors", or fluids
- antibodies circulate freely in the blood and lymph - antibodies bind to extracellular targets (bacteria, bacterial toxins, and free viruses) - antibodies inactivate temporarily and marks them for destruction by phagocytes or complement |
|
|
What are the basic characteristics of cellular/cell-mediated immunity?
|
- living cells provide the immunity
- cellular targets: virus-infected or parasite-infected tissue cells, cancer cells, and cells of foreign grafts - lymphocytes act against such targets either directly or indirectly |
|
|
What is an antigen?
|
substances that can mobilize the adaptive defenses and provoke an immune response; they are the ultimate targets of all adaptive immune responses
most are large, complex molecules (both natural and synthetic) that are not normally present in the body are perceived as intruders by our immune system |
|
|
What are the strongest antigens?
|
proteins are the strongest antigens
|
|
|
Does the whole antigen cause an immune response?
|
No, just the determinant part of the antigen
|
|
|
What are two important functional properties of complete antigens?
|
immunogenicity and reactivity
|
|
|
What is immunogenicity?
|
property of complete antigens
the ability to stimulate specific lymphocytes to proliferate (multiply) |
|
|
What is reactivity?
|
property of complete antigens
the ability to react with the activated lymphocytes and the antibodies released by immunogenic reactions |
|
|
What is a hapten?
|
small molecules--such as peptides, nucleotides, and many hormones--they're not immunogenic
|
|
|
What must a hapten do to become immunogenic?
|
they must link up with the body's own proteins and the adaptive immune system may recognize the combination as foreign and mount an attack that is harmful rather than protective
these reactions are called hypersensitivities |
|
|
What is an incomplete antigen?
|
also called a hapten, unless attached to protein carriers, haptens have reactivity but not immunogenicity
certain drugs (particularly penicillin), chemicals found in poison ivy, animal dander, detergents, cosmetics, and a number of common household and industrial products |
|
|
What are antigenic determinants?
|
certain parts of an entire antigen that are immunogenic
part of the antigen that causes an immune response antibodies and lymphocytes bind to them |
|
|
What are MHC proteins and what is their jobs?
|
protein molecules on the surface of cells (self-antigens) and are unique to an individual
job of MHC's is to tell YOU cells that YOU are YOU, DO NOT ATTACK |
|
|
What are class I MHC proteins? What antigens do they display?
|
found on the surface of virtually all body cells except RBCs; they are crucial for both activating naive CD8 cells and "informing" cytotoxic T cells that infectious microorganisms are hiding in body cells
these proteins both (1) active as antigen holders and (2) form the self part of the self-nonself complexes that cytotoxic T cells must recognize in order to kill all antigens displayed on class I MHC proteins are endogenous antigens -- fragments of proteins synthesized inside the cells |
|
|
What are class II MHC proteins? What antigens do they display?
|
typically found only on the surfaces of cells that present antigens to CD4 cells: dendritic cells, macrophages, and B cells
display antigens found outside the cells, exogenous antigens, that have been engulfed by the cell that displays them |
|
|
Where do T and B cells mature?
|
Both originate in the red bone marrow, B cells continue to mature in the red bone marrow while T cells mature in the thymus
|
|
|
What are B cells/lymphocytes?
|
oversee humoral immunity
target bacteria and viruses circulating in the blood |
|
|
If B cells are self reactive what happens?
|
they are eliminated by apoptosis (clonal deletion) or can have their receptors "edited" so they work correctly
B cells that successfully make antigen receptors are positively selected and those whose antigen receptors are self-reactive are eliminated (clonal deletion) |
|
|
What are T cells/lymphocytes?
|
non-antibody-producing lymphocytes that constitute the cell-mediated arm of adaptive immunity
targets tumors, cancer cells, and cells w/ viruses |
|
|
What is negative and positive selection of T cells?
|
Positive selection: selects T cells capable of binding to self-MHC proteins
ensures that only T cells that are able to recognize self-MHC proteins survive T cells that are unable to recognize self-MHC are eliminated by apoptosis |
|
|
What is negative selection of T cells?
|
ensures that T cells do no recognize self-antigens displayed on self-MHC, if they do they are eliminated by apoptosis
|
|
|
What is immunocompetence?
|
each lymphocyte must become able (competent) to recgnize its one specific antigen by binding to it
when B&T cells become immunocompetent, they display a unique type of receptor on their surface which enable the lymphocyte to recognize and bind a specific antigen |
|
|
What is self-tolerance?
|
each lymphocyte must be relatively unresponsive to self-antigens so that it does not attack the body's own cells
|
|
|
What are primary lymphoid organs?
|
the organs where the lymphocytes become immunocompetent (thymus and bone marrow)
|
|
|
What are secondary lymphoid organs?
|
all other lymphoid organs other than the thymus and bone marrow
|
|
|
Where do naive (unexposed) B and T cells go?
|
they are exported to the lymph nodes, spleen, and other lymphoid organs
|
|
|
What are APCs?
|
antigen-presenting cells
they engulf antigens and then present fragments of them, like signal flags, on their own surfaces where T cells can recognize them APCs present antigens to the cells that will deal with the antigens major types of cells acting as APCs are dendritic cells, macrophages, and B cells they do not respond to specific antigens, they only know that some is foreign |
|
|
How are T cells activated?
|
naive T cells can only be activated by antigens that are presented to them on MHC proteins by APCs
|
|
|
What are dendritic cells?
|
type of APC
very efficient antigen catchers move to secondary lymphoid organs most effective antigen present known--it's their only job key links between innate and adaptive immunity they initiate adaptive immune responses tailored to the type of pathogen they have encountered |
|
|
What are macrophages
|
type of APC
widely distributed throughout the lymphoid organs and CTs can activate naive T cells but often present antigens to T cells to be activated themselves can be activated by effector T cells releasing chemicals activated macrophages are true "killers" that are insatiable phagocytes and secrete bactericidal chemicals |
|
|
What are B cells in regards to APCs?
|
are a type of APC
do not activate naive T cells, instead, they present antigens to a helper T cell in order to obtain "help" in their own activation |
|
|
The ability of the adaptive immune system to respond to threats depends on...
|
1. ability to recognize antigens by binding to them
2. ability to communicate with one another so that the whole system mounts a response specific to those antigens |
|
|
What are three important aspects of adaptive immunity?
|
it is specific
it is systemic it has "memory" |
|
|
What is humoral immunity?
|
immunity conferred by antibodies present in blood plasma and other body fluids
when a B cell encounters its antigen, that antigen provokes the humoral immune response, in which antibodies specific for the antigen are made |
|
|
When is a naive B lymphocyte activated?
|
an immunocompetent but naive B cell is activated when matching antigens bind to its surface receptors and crosslink adjacent receptors together
|
|
|
What is clonal selection?
|
process during which a B cell or T cell becomes activated by binding with an antigen
when an antigen bind to the particular lymphocyte that has a receptor for it, the antigen selects that lymphocyte for further development |
|
|
What are plasma cells?
|
the antibody-secreting effector cells of the humoral response
|
|
|
What are memory cells?
|
clone cells that did not become plasma cells
can mount an almost immediate humoral response if they encounter the same antigen again the future |
|
|
What is the primary immune response?
|
occurs on the first exposure to a particular antigen
typically has a lag period of 3 to 6 days after the antigen encounter; lag period mirrors the time required for the few B cells specific for that antigen to proliferate (about 12 generations) and for their offspring to differentiate into plasma cells |
|
|
What is secondary immune response?
|
occur if and when someone is reexposed to the same antigen, whether its the second or twenty-second time
they are faster, more prolonged, and more effective becaue the immune system has already been primed to the antigen, and sensitized memory cells are already "on alert" |
|
|
What are the two ways active humoral immunity is acquired?
|
1. naturally acquired when you get a bacterial or viral infection, during which time you may develop symptoms of the disease and suffer a little (or a lot)
2. artificially acquired when you receive vaccines |
|
|
What two benefits do vaccines provide?
|
- they spare us most of the symptoms and discomfort of the disease that would otherwise occur during the primary response
- their weakened antigens provide functional antigenic determinants that are both immunogenic and reactive |
|
|
What is active humoral immunity?
|
occurs when your B cells encounter antigens and produce antibodies against them
can either be natural or artificial |
|
|
What is passive humoral immunity?
|
occurs when ready made antibodies are introduced into your body instead of being made by your plasma cells
your B cells are not challenged by antigens, immunological memory does not occur, and the protection provided by the "borrowed" antibodies ends when they naturally degrade in the body can be natural or artificial |
|
|
What is naturally acquired active humoral immunity?
|
YOU get the antigen through normal exposure, YOU develop immunity
response to a bacterial or viral infection |
|
|
What is artificially acquired active humoral immunity?
|
vaccine through either dead or attenuated pathogens
ex. flu vaccine: shot is dead, flu mist: is attenuated (weakened but still living) |
|
|
How is passive immunity conferred naturally?
|
mother's antibodies to fetus via placenta or through breast milk
|
|
|
What is a pro and con of passive humoral immunity?
|
protection is immediate, you bypass time constraints
negative is there is no memory, antibodies are gone after a few weeks |
|
|
What is artificially acquired passive humoral immunity?
|
accomplished by administering exogenous antibodies (from outside your own body) as gamma globulin, harvested from the plasma of an immune donor
the donated antibodies provide immediate protection but their effect is short-lived (two to three weeks) ex. anti-venom for snake bite or spider bite, tetanus protection is immediate but ends when antibodies naturally degrade in the body |
|
|
What is an example of both naturally and artificially acquired passive humoral immunity?
|
Rabies
injfection of gamma globulins (preformed antibodies) when first infected (passive) to nail any parts of virus circulating in blood immediately active part of treatment is dead virus series of shots several weeks later because rabies virus can go dormant - prevents secodnary infection months later because body has produced memory cells |
|
|
What does a vaccine target in regards to lymphocytes?
|
targets only one type of helper T cell (vaccines fail to fully establish cellular immunological memory) T helper cells help B lymphocytes recognize antigen better --- facilitates introduction
|
|
|
What are antibodies?
|
constitute the gamma globulin part of blood proteins
they are proteins secreted in response to an antigen by effector B cells called plasma cells, and the antibodies bind specifically with that antigen formed in response to an incredible number of different antigens can be grouped into one of five Ig classes |
|
|
What do the effector regions of the antibody dictate?
|
the cells and chemicals of the body the antibody can bind to
how the antibody class functions to eliminate antigens |
|
|
IgM immunoglobulin class - where are they found and how do they work?
|
they are the first immunoglobulin class secreted by plasma cells during the primary response
presence of IgM usually indicates infection readily fixes and activates complement clumps the antigens together common in blood plasma and lymphatic system virtually always attached to B cells; B cell receptor |
|
|
What are the five antibody/immunoglobulin classes?
|
IgM
IgA IgD IgG IgE |
|
|
IgA immunoglobulin class - where are they found? how do they work?
|
present in secretions like mucus, saliva, breast milk, and intestinal juices
its job is to prevent virus or bacteria from attaching to the tissue (including mucous membranes and the epidermis) seen in babies who are breastfed and receive from mother |
|
|
IgD immunoglobulin class - where are they found and how do they work?
|
found on the B cell surface
functions as a B cell antigen receptor (possibly functions in recognition) |
|
|
IgG immunoglobulin class - where are they found and how do they work?
|
most abundant antibody in plasma, produced after IgM
present late in primary response and is the first antibody present in secondary response crosses placenta to give fetus immunity if mom has infection very effective against viruses circulating in blood and bacteria readily fixes and activates complement |
|
|
IgE immunoglobulin class - where are they found and do they work?
|
releases histamine and other chemicals that mediate inflammation and an allergic reaction
parasitic worm infections and in people with allergies found in small amounts in various fluids and secretions |
|
|
What are the defensive mechanisms used by antibodies?
|
they cannot destroy antigens but they can inactivate antigens and tag them for destruction
neutralization, agglutination, precipitation, and complement fixation and activation |
|
|
What is neutralization?
|
defensive mechanism used by antibodies
simplest defensive mechanism occurs when antibodies block specific sites on viruses or bacterial exotoxins and prevent these antigens from binding to receptors on tissue cells phagocytes eventually destroy the antigen-antibody complexes |
|
|
Which antibody classes are good at neutralization?
|
IgM and IgA
they cause antigens to clump together making them more attractive to macrophages |
|
|
What is agglutination?
|
antibody defensive mechanism
occurs when antibodies bind the same determinant on more than one cell-bound antigen cross-linked antigen-antibody complexes agglutinate ex. is the clumping of mismatched blood cells |
|
|
What is precipitation?
|
antibody defensive mechanism
soluble molecules (instead of cells) are cross-linked into large complexes that settle out of solution soluble molecules are cross-linked and complexes precipitate and are subject to phagocytosis not in cells---causing molecules to come out of solution, when they are out they are very attractive to cells |
|
|
What is complement fixation and activation?
|
antibody defensive mechanism
the chief antibody defense used against cellular antigens, such as bacteria or mismatched RBCs several antibodies bind close together on the same cell, the complement-binding sites on their stem regions align which triggers complement fixation into the antigenic cell's surface followed by cell lysis this amplifies the inflammatory response, opsonization, enlists more and more defensive elements |
|
|
What are monoclonal antibodies and why are they useful?
|
commercially prepared pure antibody that are produced by hybridomas (cell hybrids - fusion of a tumor cell and a B cell) which proliferate indefinitely and have the ability to produce a single type of antibody
they are used in research, clinical testing, and cancer treatment (very effective against certain tumors) ---- ex. strep tests and eldon cards ---- immediate reaction to detect antigen |
|
|
What is cell mediated immunity?
|
involves T cells
occurs when antigens are presented to a T lymphocyte some activated T cells directly kill body cells infected by viruses or bacteria, abnormal or cancerous body cells, and cells of infused or transplanted foreign tissues --- other T cells release chemicals that regulate the immune response |
|
|
What are the two types of surface receptors of T cells?
|
- T cell antigen receptors
- cell differentiation glycoproteins (sugar proteins): CD4 & CD8 cells |
|
|
When activated CD4 and CD8 cells differentiate into what three major kinds of effector cells of cellular immunity?
|
helper T cells, cytotoxic T cells, and regulatory T cells
|
|
|
What are helper T cells?
|
usually come from CD4 cells
help activate B cells, other T cells, and macrophages, and direct the adaptive immune response help B cells differentiate and divide in humoral immunity role is more important in cell-mediated immunity |
|
|
What are cytotoxic T cells?
|
come from CD8 cells
destroy any cells in the body that harbor anything foreign comparable to natural killer cells except only destroys specific antigens |
|
|
What are regulatory T cells?
|
come from CD4 cells
moderate the immune response make sure immune response is appropriate, prevents autoimmune response |
|
|
What are the targets of cell-mediated immunity?
|
body cells infected by viruses or bacteria (Lyme disease or rocky mountain spotted fever), abnormal or cancerous cells, cells of infused or transplanted foreign tissue
|
|
|
How does antigen recognition work?
|
immunocompetent T cells are activate when their surface receptors bind to a recognized antigen (nonself)
T cells must simultaneously recognize nonself (the antigen) and self (an MHC protein of a body cell) |
|
|
What are class I MHC proteins? Where are they found?
|
they bind with fragment of a protein synthesized in the cell (endogenous antigen) and are recognized by CD8
inform cytotoxic T cells of the presence of microorganisms hiding in cells are crucial for both activating naive CD8 cells and "informing" cytotoxic T cells that infectious microorganisms are hiding in body cells act as antigen holders and form the self part of the self-nonself complexes that cytotoxic T cells must recognize in order to kill are found on the surface of virtually all body cells except RBCs |
|
|
What are class II MHC proteins? Where are they located?
|
typically found only on the surfaces of cells that present antigens to CD4 cells (dendritic cells, macrophages, and B cells)
bind with fragments of exogenous antigens (antigens from outside the cells) that have been engulfed and broken down in a phagolysosome and are recognized by helper T cells (CD4) |
|
|
How are T cells activated?
|
APCs (most often a dendritic cells) migrate to lymph nodes and other lymphoid tissues to present their antigens to T cells
T cell activation is a two-step process: antigen binding and co-stimulation both steps usually occur on the surface of the same APC and both steps are required for clonal selection the two-signal sequence acts as a safeguard to prevent the immune system from destroying healthy cells---without this safeguard cytotoxic T cells could become activated leading to widespread damage of healthy cells |
|
|
What is antigen binding?
|
First step of T cell activation
T cell antigen receptors bind to an antigen-MHC complex on the surface of an APC TCRs must perform double recognition: they must recognize both MHC (self-antigen) and the foreign antigen it displays CD4 and CD8 proteins that distinguish the two major T cell groups are adhesion molecules that help bind cells together during antigen recognition |
|
|
What is co-stimulation?
|
second step of antigen recognition
requires T cell binding to other surface receptors on an APC co-stimulatory signals are molecules that appear on the surfaces of APCs in tissues that are damaged or invaded by pathogens |
|
|
What is anergy?
|
occurs if a T cell bind to an antigen without receiving the co-stimulatory signal
the T cell becomes tolerant to that antigen and is unable to divide or secrete cytokines it is a state of unresponsiveness to an antigen |
|
|
What are cytokines? What do they do?
|
chemical messengers involved in cellular immunity
a general term for mediators that influence cell development, differentiation, and responses in the immune system include interferons and interleukins all activated T cells secrete one or more other cytokines that help amlify and regulate a variety of adaptive and innate immune responses ---- others enhance the killing power of macrophages; and still others are inflammatory chemicals |
|
|
What are interleukins? What are their roles?
|
promote T cell proliferation
interleukin 1, released by macrophages, stimulates T cells to liberate interleukin 2 and to synthesize more IL-2 receptors. IL-2 is a key growth factor - it sets up a positive feedback cycle that encourages activated T cells to divide even more rapidly |
|
|
What are the roles of helper T cells?
|
play central role in adaptive immunity --- mobilize both its humoral and cellular arms
help activate B and T cells and induce B and T cells to proliferate without them there is no adaptive immune response their cytokines furnish the chemical help needed to recruit other immune cells |
|
|
What do cytotoxic T cells do and where do they circulate? What are their main targets?
|
they directly attack and kill other cells; they do not have to enter or engulf a cell to kill it
they roam the body, circulating in and out of the blood and lymph and through lymphoid organs in search of body cells displaying antigens that the cytotoxic T cells recognize their main targets are virus-infected cells but they also attack tissue cells infected by certain intracellular bacteria or parasites, cancer cells, and foreign cells introduced into the body by blood transfusions or organ transplants |
|
|
What are the two main mechanisms that cytotoxic T cells use to destroy antigens?
|
1. involves perforins (create pores through which granzymes enter the target cell) and granzymes (stimulates apoptosis)
2. binds to a specific membrane receptor on the target cell that stimulates the target cell to undergo apoptosis (Fas receptor on target cell and stimulates apoptosis) |
|
|
How do Natural Killer cells work in regards to their mechanisms to kill their target cell?
|
similar to cytotoxic T cells however they do not look for foreign antigen displayed on class I MHC proteins
they search for other signs of abnormality, including the lack of class I MHC or the presence of antibodies coating the target cell NK cells stalk abnormal or foreign cells in the body that cytotoxic T cells can't "see" |
|
|
What is immune surveillance?
|
NK cells and cytotoxic T cells roam the body adhering to and crawling over the surfaces of other cells, examining them for markers they might recognize
NK cells check to make sure each cell has "identity flags" whereas cytotoxic T cells check the "identity flags" to see if they look the way they are supposed to |
|
|
What to T regulatory cells do?
|
dampen (moderate) the immune response by direct contact or by inhibitory cytokins
important in preventing autoimmune reactions because they suppress self-reactive lymphocytes outside the lymphoid organs researchers hope to use them to induce tolerance to transplanted tissue and to lessen the severity of autoimmune diseases |
|
|
What is AIDS?
|
virus attacks the T helper cells
transmitted via secretions (blood, semen, vaginal secretions) only infectious disease which actually attacks immune cells caused by HIV effects cell-mediated more than humoral 10% of all people are resistant to HIV - has to do with receptors on the body's cell considered chronic now |
|
|
What are autoimmune diseases? What are some examples?
|
occur when the body loses ability to distinguish self from foreign body; the body produces antibodies against itself and T cytotoxic cells can attack tissue
MS - attack myelin sheath of nerve cells Type I Juvenile diabetes - breast feeding is thought to reduce risk of SLE RA - attacks joints issues with CD4 and T helper cells |
|
|
What are lymphomas? What are the two types?
|
cancer of the lymphocytes; there is a tumor that consists of all lymphocytes
often originates in lymph nodes 1. Hodgkins - abnormal B lymphocytes (fever, night sweats, weight loss, fatique, 85-90% cure rate with chemo and radiation) 2. Non Hodgkins - abnormal B or T lymphocytes (70% cure rate) |
|
|
What is the staging process for lymphoma?
|
1. cancer is only in lymph node
2. two or more infected lymph nodes 3. both sides of the diaphragm (upper and lower body halves) 4. tissue is outside the lymph nodes |
|
|
What is cancer? Why does it spread? Diagnosis? Treatments? New Treatments?
|
- abnormal cell growth with ability to spred
- travels via lymphatic system, can cross blood brain barrier - diagnosed using blood, urine, PET, x-rays, U/S, genetics - treatments include chemo, radiation, surgery - new biological treatments involve injecting interleukin 2s (reduce T-reg role in the immune response = increased T cytotoxic activity); possibility of injecting cytotoxic T cells, still being researched |
|
|
What is the major function of the respiratory system?
|
to supply the body with oxygen and dispose of carbon dioxide
|
|
|
What are the four processes that the respiratory system uses to accomplish its main goal?
|
pulmonary ventilation - air movement into and out of the lungs
external respiration - gas exchange between alveoli and blood transport of respiratory gases - between lungs and tissues internal respiration - gas exchange between blood and tissues |
|
|
What are the two divisions of the respiratory system?
|
the respiratory zone and the conducting zone
|
|
|
What is the respiratory zone?
|
the actual site of gas exchange
composed of the respiratory bronchioles, alveolar ducts, and alveoli, all microscopic structures |
|
|
What is the conducting zone?
|
includes all other respiratory passageways
conduits of gas exchange sites conducting zone organs cleanse, humidify, and warm incoming air |
|
|
Nose - description and function
|
jutting external portion is supported by bone and cartilage, internal nasal cavity is divided by midline nasal septum and lined with mucosa
produces mucus; filters, warms, and moistens incoming air; resonance chamber for speech |
|
|
paranasal sinuses - desription and function
|
mucosa-lined, air filled cavities in cranial bones surrounding nasal cavity
same as for nasal cavity except no receptors for smell; also lighten skull |
|
|
Pharynx - description and function
|
passageway connecting nasal cavity to larynx and oral cavity to esophagus. Three subdivisions: naso, oro, and laryngo
passageway for air and food |
|
|
Larynx - description and function
|
connects pharynx to trachea; has framework of cartilage and dense CT; opening (glottis) can be closed by epiglottis or vocal folds
air passageway; prevents food from entering lower respiratory tract |
|
|
Trachea - description and function
|
flexible tube running from larynx and dividing inferiorly into two main bronchi; walls contain C-shaped cartilages that are incomplete posteriorly where connected by trachealis
air passageway; cleans, warms, and moistens incoming air |
|
|
Bronchial tree - description and function
|
consists of right and left main bronchi, which subdivide within the lungs to form lobar and segmental bronchi and bronchioles; bronchiolar walls lack cartilage but contain complete layer of smooth muscle; constriction of this muscle impedes expiration
air passageways connecting trachea with alveoli; cleans, warms, and moistens incoming air |
|
|
Alveoli - description and function
|
microscopic chambers at termini of bronchial tree; walls of simple squamous epithelium overlie thin basement membrane; external surfaces are intimately associated with pulmonary capillaries; special alveolar cells produce surfactant
main sites of gas exchange; reduces surface tension; helps prevent lung collapse |
|
|
Lungs - description and function
|
paired composite organs that flank mediastinum in thorax; composed primarily of alveoli and respiratory passageways; stroma is fibrous elastic CT, allowing lungs to recoil passively during expiration
house respiratory passages smaller than the main bronchi |
|
|
Pleurae - description and function
|
serous membranes; parietal pleura lines thoracic cavity; visceral pleura covers external lung surfaces
produce lubricating fluid and compartmentalize lungs |
|
|
What divides the nasal cavity and what kind of tissue is it?
|
the septum divides the nasal cavity and is hyaline cartilage
|
|
|
What tissue comprises the respiratory mucosae?
|
pseudostratified ciliated columnar epithelium
|
|
|
What tissue is located in the nasopharynx?
|
pseudostratified cilliated columnar epithelia
|
|
|
What epithelial tissue is in the oropharynx?
|
epithelial tissue changes from pseudostratified to stratified squamous
|
|
|
What tissue is present in the laryngopharynx?
|
stratified squamous epithelium
|
|
|
What tissue surrounds the trachea?
|
cartilagenous rings of hyaline cartilage
|
|
|
What kind of tissue is present in the bronchioles and onward to the terminal bronchioles?
|
simple cuboidal epithelium
|
|
|
What tissue increases in amount as bronchi become smaller?
|
smooth muscle
|
|
|
In the alveoli what two cells types are present?
|
type I cells - simple squamous epithelium
type II cells - simple cuboidal epithelium |
|
|
What kind of fibers surround alveoli?
|
elastic collagen fibers
|
|
|
What are the three functions of the pleura?
|
lubricate, air pressure, and separation of the lungs from the heart
|
