Lymphatic and Immune Flashcards
(115 cards)
1
Q
functions of the lymphatic system
A
- drain excess interstitial fluid to maintain fluid balance
- transport dietary lipids and lipid soluble vitamins (ADEK) in GI tract
- carry out immune responses- highly specific against microbes
2
Q
lymphatic transport
A
one way system where lymph flows towards the heart
3
Q
lymphatic capillaries
A
similar to blood capillaries but:
- they are very permeable
- they have loosely joined endothelial mini valves-one way gates that do not allow lymph to escape from the capillaries
- collagen fillaments that withstand interstitial pressure and remain open
during inflammation, lymphatic capillaries can absorb cell debris, pathogens, and cancer cells because they cleanse and absorb
4
Q
lacteals
A
special type of lymphatic capillary that is present in intestinal mucosa to absorb digested fat and deliver chyle to the blood
5
Q
lymphatic collecting vessels
A
have the same 3 tunics as veins
thinner walls with more internal valves
anastomose more frequently
collecting vessels in the skin travel with superficial veins
deep vessels travel with arteries
nutrients are supplied by the branching vaso vasorum
6
Q
lymphatic trunk
A
formed by the union of the largest collecting ducts
paired lumbar, bronchomediastinal, subclavian, and jugular trunks
single intestinal trunk
7
Q
lymphatic ducts
A
receive lymph from trunks into one of 2 large ducts
- right lymphatic duct- drains upper right arm, and right side of the head and thorax
- thoracic duct-arises from cisterna chyli and drains the rest of the body
8
Q
the right lymph duct and the thoracic duct drain lymph
A
into the junction of the internal jugular and subclavian veins which returns fluid to the blood
9
Q
differences bt the blood capillaries and the lymphatic capillaries
A
similar but lymph capillaries are
- very permeable and loosely joined with endothelial mini valves- one way gates that do not allow lymph to escape
- collagen filaments that can withstand interstitial pressure and remain open
10
Q
source of lymph
A
interstitial fluid filtered out of the blood
called lymph once it has entered the lymphatic vessels
20L fluid filtered out of the blood each day
17L is returned to the blood
3L goes into the lymph vessels
11
Q
lymph transport
A
no pumping organ-one way flow to the heart via low pressure conduits
skeletal and respiratory pumps
pulsations of nearby arteries
contractions of smooth muscle in the walls of the lymphatics
12
Q
lymph nodes location
A
aggregations that occur near body surfaces in
inguinal, auxillary, and cervical regions of the body
imbedded in CT and clustered around lymph vessels
13
Q
functions of lymph nodes
A
- filtration- macrophages destroy microorganisms and debris
2. immune system activation-monitor for antigens and mount attack against them
14
Q
structure of a lymph node
A
bean shaped organ surrounded by a fibrous capsule
trabeculae exteneded inward from the capsule to divide the node into compartments
2 histologically distinct regions: cortex and medulla
15
Q
lymph node cortex
A
contains follicles with germinal centers that are heavy with dividing B cells
dendritic cells nearly encapsulate the follicles
the deep cortex houses the T cells in transit that circulate continuously among the blood, lymph nodes and lymphatic stream
16
Q
lymph node medulla
A
medullary cords extend from the cortex and contain B cells, T cells, and plasma cells
throughout the node are lymph sinuses that are crisscrossed by reticular fibers
macrophages reside on the reticular fibers and phagocytize foreign matter
17
Q
circulation of a lymph node
A
lymph enters via afferent vessels
meanders through sinuses and exits the node at the hilum via efferent vessels
18
Q
because there are more afferent vessels than efferent vessels
A
lymph stagnates somewhat in the node and takes time to pass so that it can be filtered
19
Q
other lymphoid organs
A
spleen
thymus
tonsils
20
Q
spleen
A
largest lymphoid organ
located on the left side of the abdominal cavity beneath the diaphragm. served by the splenic artery/vein
21
Q
spleen white pulp
A
contains mostly lymphocytes suspended on reticular fibers and involved in immune functions
22
Q
spleen red pulp
A
remaining splenic tissue
removes old RBC and platelets, stores platelets, removes blood borne pathogens
also in charge of hematopoiesis during fetal life
23
Q
functions of the spleen
A
site of lymphocyte proliferation
immune surveillance and response
uses macrophages in sinsues to remove debris/foreign matter from the blood
stores RBC break down products for later reuse
stores blood platelets
fetal hematopoiesis
-macrophages salvage/store iron for later use by bone marrow
24
Q
thymus
A
bilobed organ in the neck that contains an outer cortex and inner medulla
it has no follicles so there are no B cells
cortex-contains densely packed lymphocytes and scattered macrophages
medulla- contains fewer lymphocytes and has thymic (hassalls) corpuscles that are involved in the development of regulatory T cells to prevent autoimmune
25
function of the thymus
secretes hormones Thymosin and Thymopoietin that causes T lymphocytes to become immunocompetent and able to recognize specific antigens
26
the size of the thymus varies with age
infants- located in the inferior neck and extends into the mediastinum where it partially overlies the heart
childhood- increases in size and is most active
adolescence-thymus stops growing and gradually atrophies
old age- almost entirely replaced with fibrous and fatty tissue
27
the thymus differs from other lymphoid organs because
it functions strictly in T lymphocyte maturation
| the stroma consists of epithelial cells that secrete hormones
28
tonsils
the simplest of lymphoid organs
forms a ring of lymphatic tissue around the pharynx to gather and remove patho entering the pharnyx in food or air
lymphoid tissue of tonsils contains follicles with germinal centers
tonsil masses are not fully encapsulated- crypts trap and destroy bac and particulate matter
29
palatine tonsils
largest
located at either side of the posterior end of the oral cavity
below the soft palate
30
lingual tonsils
collection of lymphoid follicles at the base of the tongue
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pharyngeal tonsils
adenoids
| located in the posterior wall of the pharynx
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tubal tonsils
surround the openings of the auditory tubes into the pharynx
33
lymphoid cells
lymphocytes are the main cells involved in the immune response
T and B cells protect the body against antigen
34
antigens
```
anything the body perceives as foreign
bacteria/toxins
viruses
mismatched RBC
cancer cells
```
35
T cells
manage the immune response
| attack and destroy foreign cells
36
B cells
produce plasma cells that secrete antibodies
| antibodies then immobilize antigens
37
macrophages
phagocytize foreign substances and help activate T cells
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dendritic cells
spiny looking cells with functions similar to macrophages
39
reticular cells
fibroblast like cells that produce a stroma or network that supports other cell types in lymphoid organs
40
lymphoid tissues
MALT
mucosa associated lymphatic tissue
protects the digestive and respiratory systems from foreign matter
41
malt: peyers patches
isolated clusters of lymphoid tissue found in the ileum
| similar to tonsils in structure
42
malt: peyers patches and the appendix
destroy bacteria preventing them from breaching the intestinal wall
generate memory lymphocytes for long term immunity
43
malt: lymphoid nodules in walls of the bronchi
help protect the respiratory tract
44
what distinguishes the innate defense system from the adaptive defense system
innate- 1st and 2nd line of defense
| INFLAMMATION
45
innate first line: skin
keratin presents a physical barrier to most microorganisms and is resistant to weak acid, bases, bacterial enzymes, and toxins
acidity of 3-5 inhibits bacterial growth
sebum has chemicals toxic to bacteria
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innate first line: mucous membranes and secretions
stomach mucosae- HCl and protein digesting enzymes
saliva/lacrimal fluid-lysozyme
respiratory mucous-traps microorgs and cilia help to remove it
ears- wax to protect internal and middle ear
urine to flush out bacteria and acidity to inhibit growth
47
innate first line: bacteria
mutualistic relationship
colonization of an environment so other bacteria cannot
they produce chemicals to inhibit growth of other microbes and keep the immune system alert and ready
48
innate second line: phagocytes
macrophages are chief phagocytic cells
- free macro wander and search for cellular debris
-kupffer cells in the liver and spleen and microglia in the brain are fixed macrophages
dendrites are most important in the start of the immune system
neutrophils become phago when encountering infectious material
phagocytosis allows the processing of antigens
eosinophils phago paracytic worms
mast cells bind and ingest a wide array of bac
49
innate second line: natural killer cells
small distinct group of large granule lymphocytes that react non specifically and eliminate cancerous/virus infected cells
kill their target cell by releasing perforins and other cytolytic chemicals
secrete potent chemicals to enhance the inflammatory response
50
innate second line: inflammation
triggered whenever body tissues are injured to prevent the spread of damaging agents, dispose of cell debris/patho, and set the stage for repair
51
inflammation- leukocytosis
first step
neutrophils are released from the bone marrow in response to leukocytosis inducing factors that are released by injured cells
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inflammation- margination
second step
| neutrophils cling to the walls of capillaries in the injured area
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inflammation-diapedesis
third step
| neutrophils squeeze through capillary walls and begin phago
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inflammation-chemotaxis
last step
| inflammatory chemicals attract more neutrophils to the injury site
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innate second line: anti microbial proteins
attack microorg directly and hinder their ability to produce through interferons or complement
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anti microbial proteins
| interferon
induced at an early stage in viral infection to hinder replication
activate macrophages and mobilize NK
57
type of interferon secreted by lymphocytes T cells and NK
gamma interferon
58
alpha interfereon
secreted by most other WBC
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beta interferon
secreted by fibroblasts and epithelial cells
60
how interferons work
1. genes that synth IFN are activated when a virus invades a host cell
2. interferon molc leave the infected cell and enter neighboring cells
3. interferon stimulates the neighboring cells to activate genes for PKR an antiviral protein
4. PKR non specifically blocks viral reproduction in the neighboring cell
61
antiviral proteins: complement
20 or so proteins that circulate the body in inactive form
amplifies all aspects of the inflammatory response
kills bacteria and other certain cell types
also can be used in the 3rd line of defense
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how complement is activated
| classical pathway
depends on the binding of antibodies to invading organisms
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how complement is activated
| alternative pathway
triggered by interaction with molc present on microorganisms
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how complement pathways work
both pathways converge on C3 which cleaves into C3a and C3b to cause
opsonization, inflammation, and formation of the membrane attack complex MAC which inserts into the membrane of a cell and allows ions, water and other small molecules to pass freely through the pore resulting in lysis
65
innate second line
| fever
abnormally high body temperature in response to invading microorg
66
fever can be dangerous because
if it is to high it can denature enzymes
67
moderate fever is beneficial because
it causes the liver and spleen to sequester iron/zinc needed by miccroorg
increases metabolic rate to speed up tissue repair
causes immune cells to become more agressive in phagocytosis and can also inhibit bacteria growth
68
cardinal signs of inflammation
redness, heat, swelling, pain
| caused by damage to the body tissues
69
toll like receptors
located in macrophages and cells lining the GI/respiratory tract
recognizes specific components conserved among microorg
activated TLR trigger the release of cytokines that promote inflammation
they are pattern recognition receptors that do not alter so they are directed against key pathogen assoc molcule which are evolutionarly conserved
70
toll like receptors protect you from
evolved pathogens
71
adaptive 3rd line of defense
| antigens
substances that can mobilize the immune system and provoke an immune response
72
complete antigens
ultimate targets of all immune responses
mostly large complex molecules not normally found in the body such as protein, nucleic acids, some lipids and large polysaccarides
only certain parts of the entire antigen are immunogenic
73
haptens, incomplete antigens
small molc such as peptides, nucleotides and many hormones that are not immunogenic but are reactive when attached to protein carriers
if they link up with the bodies proteins, the adaptive immune system may recognize them as foreign and mount a harmful allergy attack
no allergy resp unless bound w other molc
74
types of self antigens MHC proteins
```
class I- found on all body cells except the RBC because they have ABO markers ( these provide the means for signaling to T cytotoxic cells that infectious microorg are hiding in body cells)
class II-found on certain cells of the immune response, only when pathogens are in the area
```
75
cells of the adaptive immune response
lymphocytes
| antigen presenting cells MHC II
76
cells of the adaptive immune response
| lymphocytes
immature lymphocytes released from bone marrow are essentially identical
whether a lymphocyte becomes a B/T cell depends on where in the body it becomes immunocompetent
B cells mature in the bone marrow and oversee humoral immunity
T cells mature in the thymus- they are non antibody producing cells that constitute the cell mediated immunity
77
event signaling that B/T cells are immunocompetent
display a unique type of receptor that responds to a distinct antigen
they become immunocompetent before they encounter antigens they may later attack
immunocompetence starts developing during fetal life, during this development the ability to tolerate self occurs
once immunocompetent they are transfered to a secondary lymphoid tissue where antigen encounters occur
78
it is the ________not the antigens that determine which foreign substances our immune system will recognize and resist
genes
79
cells of the adaptive immune system
| antigen presenting cells
MHC II
| engulf foreign particles and present fragments of antigens on their own surface to be recognized by T cells
80
types of APC
| dendritic cells
most important
initiator of adaptive immunity
usually in CT and epidermis, migrates to the lymph nodes and 2nd lymphoid organs and presents antigens to B/T cells
81
types of APC
| macrophages
stay at the site of infection
| similar to dendritic cells but can also secrete soluble proteins that activate T cells and B cells?
82
types of APC
| activated B cells
produce antibodies
83
first step of humoral immunity
| antigen challenge
first encounter bt antigen and naive immunocompetent cell
B cells have class II MHC proteins (also found in T cells and APC)
class II MHC proteins bind to antigens that are later engulfed, they then migrate to the cell membrane and display the antigenic peptide for recognition by CD4 T helper cells
usually takes place in spleen or other lymphoid organ
84
second step of humoral immunity
| clonal selection
a naive immunocompetent B cell is activated when antigens bind to its surface receptors and T cell interactions occur
the B cells are stimulated and quickly multiply resulting in an army of all alike cells bearing the same antigen specific receptors
the antigen selects a cell by choosing a lymphocyte with complimentary receptors
85
fate of the clones
most clone cells become antibody secreting plasma cells that secrete at 2000 molc/sec
others become memory cells that can mount immediate response to subsequent exposures of the same antigens
86
third step of humoral immunity
| production of antibodies
antibodies= the most important ammunition of humoral immunity
secreted antibodies/immunoglobulins are capable of binding specifically with the antigen
87
5 classes of antibodies
IgA, IgD, IgE, IgG, IgM
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IgD
monomer attached to the surface of B cells
| important in B cell activation
89
IgM
pentamer released by plasma cells during the primary immune response
can bind 10 antigens
90
IgG
monomer that is the most abundant and diverse antibody in primary and secondary response loc in the blood
91
IgA
dimer that helps prevent attachment of pathogens to epithelial cell surfaces
predominant in fluids-mucus, saliva, tears
92
IgE
monomer that binds to mast cells and basophils causing release of histamine when activated to mediate allergic responses
93
active humoral immunity
YOU make antibodies-memory from immune response- B cells encounter antigens and produce antibodies against them
natural-memory response from being sick of bacterial/virus
artificial-memory from response to a vaccine of dead/attenuated pathogens
94
passive humoral immunity
you are given antibodies; B cells are not challenged by antigens, there is no immunological memory
natural- mother to the fetus via placenta
artificial- injection of a serum like gamma globulin
95
how do vaccines protect against common childhood illnesses
they introduces dead/attenuated pathogens so that the B cells encounter the antigens and produce antibodies against them to form memory immunity to protect the child when that pathogen is encountered again
96
max is bitten by a rattle snake what would he be given
an injection of antivenom
| which is an artificially acquired passive humoral immunity from the injection of a serum
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mechanism of antibody diversity
genes produce the variability
98
antibody targets
antibodies themselves do not destroy antigens; they inactivate and tag them form destruction by the killer parts of the immune system
99
defensive mechanisms used by antibodies are
precipiation
lysis by complement fixation
aggultination
neutralization
100
most abundant antibody in the blood
IgG
101
secreted first in the primary immune response
IgM
102
most abundant in fluid like secretions
IgA
103
immunological memory- primary immune response
cellular differentiation and proliferation, which occurs on the first exposure to a specific antigen
lag period of 3-6 days after the antigen challenge
peak levels of plasma antibody achieved in 10 days and then antibody levels decline
104
immunological memory- secondary response
re-exposure to the same antigen
sensitized memory cells respond within hours
antibody levels peak in 2 to 3 days at much higher levels than in the primary response
105
cell mediated immune response
needed because antibodies are useless against intracellular antigens
used T cells to target cells infected with virus, bacteria, intracellular parasites, abnormal/cancerous, and cells of infused/transplanted foreign tissue
106
major cells types in cell mediated immunity
CD4- t4 cells that are primarily T helper cells
CD8- t8 cells that are T cytotoxic cells that destroy cells harboring foreign antigens
regulatory T cells or T suppressor cells that close down the immune response after invading microorg are destroyed
memory T cells confer immediate protection as well as the capacity to mount a more rapid/effective secondary immune response
107
job of T cells is to simultaneously recognize the self and the non self
nonself= antigen
self- an MHC protein of a body cells- Class 1
-always recognized by CD8 T cells/ Tcytotoxic cells
-can tell if infectious microorg is hiding in the body
108
step one of T cell activation
antigen binding
T cell antigen receptors TCRs bind to antigen MHC protein complex
MHC 1 binding activates the cell immune response
MHC 2 binding activates the humoral response
109
step 2 of T cell activation
co stimulation
before a T cell can undergo clonal expansion, it must recognize or or more co stimulatory signals such as cytokines that stimulate proliferation of other immune cells
T cells that are activated enlarge proliferate and form clones, they differentiate and perform functions according to their T cell class
110
when T cells are bound in absence of Co stimulators
they become tolerant to the antigen, are unable to divide, and do not secrete cytokines
111
type of T cell that is most important during cell mediated and humoral immunity
T helper cell
regulatory cells that play a central role in the immune response
once primed by APC they chemically or directly stimulate proliferation of other T cytotoxic cells and stimulate B cells that have already become bound to the antigen
without T helper cells there is no immune response
112
cytotoxic T cell
Tc cells or killer T cells are the only T cells that can directly attack and kill other cells
they circulate through the body in search of body cells that can directly attack and kill other cells
they target
virus infected, cells w intracellular bac/parasites, cancer, and foreign cells from transplants
113
how Cytotoxic T cells work
release perforin into the membrane causing cell lysis by creating transmembrane pores
secrete lyphotoxin to fragment target cell DNA
secrete gamma interferon to stimulate phagocytosis by macrophages
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T cell that recognizes antigens on class II MHC
T helper
115
cells that display MHC II proteins
dendritic, macrophages, activated B cells
