ch21 lymphatic Flashcards
(217 cards)
1
Q
what is the immune system?
A
a cell population that inhabits all organs and defends the body from agents of disease
2
Q
What is the lymphatic system?
A
Network of organs and vein-like vessels that recover fluid
3
Q
What are the functions of the lymphatic system?
A
Fluid recovery
Immunity
Lipid absorption
4
Q
What is lymph?
A
A clear colourless fluid, similar to plasma, but low in protein.
Chemical composition varies in different locations
5
Q
Where/How does lymph originate?
A
It originates as extracellular fluid drawn into lymphatic capillaries
6
Q
what is a specific feature of lymphatic capillaries that differentiates them from other capillaries ?
A
They are non continuous (Terminal lymphatics)
7
Q
What is the lymphatic capillary wall made up of?
A
Endothelial cells overlapping eachother like roof tiles
8
Q
Lymphatic capillaries are found in most tissues, apart from?
A
CNS, cartilage, cornea, bone, and bone marrow
9
Q
How are lymphatic capillaries tethered to surrounding tissues?
A
protein filaments
10
Q
The gaps between cells in the wall of a lymphatic capillary are large enough to allow what to pass through?
A
Bacteria and cells
11
Q
What is the mechanism of fluid moving in and out of lymphatic capillaries?
A
Endothelium creates valve-like flaps that open when interstitial fluid pressure is high and close when it is low
12
Q
describe the anatomy of the larger lymphatic vessels.
A
Composed of three layers
Tunica interna
Tunica media
Tunica externa
13
Q
Other than moderating flow of fluid in and out of vessels, what is another function of lymphatic valves?
A
prevent backflow of lymph
14
Q
How many lymphatic trunks are there?
A
6
15
Q
Name the lymphatic trunks
A
Jugular
subclavian
bronchomediastinal
intercostal
intestinal (unpaired)
lumbar
16
Q
Name the 2 collecting ducts
A
Right lymphatic duct
Thoracic duct
17
Q
What is the function of the right lymphatic duct?
A
receives lymph from right arm, right side of head and thorax; empties into right subclavian vein
18
Q
What is the function of the thoracic duct?
A
receives lymph from below diaphragm, left arm, left side of head, neck, and thorax; empties into left subclavian vein
19
Q
Which of the collecting ducts is the larger?
A
Thoracic duct
20
Q
Where does the thoracic duct originate?
A
begins as a prominent sac in abdomen called the cisterna chyli
21
Q
What significantly increases lymphatic return?
A
Exercise
22
Q
Does lymph flow at low pressure low speed, or high pressure high speed?
A
Low pressure
Low speed
23
Q
What mechanisms aid the flow of lymph?
A
rhythmic contractions of lymphatic vessels
Skeletal muscle pump
Arterial pulsation
24
Q
Plasma cells are also known as
A
B cells
25
What are B cells also known as
plasma cells
26
What are natural killer (NK) cells?
Large lymphocytes that attack and destroy bacteria, transplanted tissue, host cells infected with viruses or that have turned cancerous
27
What are B lymphocytes? (B cells)
lymphocytes that when activated, become plasma cells that produce antibodies
28
What are T lymphocytes (T cells)
Lymphocytes that mature in the thymus
29
What are macrophages?
Large phagocytic cells of connective tissue
30
What cell does a macrophage develop from?
Monocytes
31
Name the functions of macrophages
Phagocytize tissue debris, dead neutrophils, bacteria and other foreign matter
Antigen presenting cell
32
What is an antigen presenting cell (APC)?
A cell that processes foreign matter and displays antigenic fragments to certain T cells alerting immune system to the presence of the enemy
33
What are dendritic cells?
Branched, mobile APCs found in epidermis, mucous membranes, and lymphatic organs
34
What is the function of a dendritic cell?
Alert immune system to pathogens that have breached the body surface
35
What is a reticular cell?
Branched stationary cells that contribute to the stroma of a lymphatic organ
36
How does a reticular cell function?
Engulfs pathogens using receptor mediated endocytosis
37
What is lymphatic (lymphoid tissue)
aggregations of lymphocytes in the connective tissues of mucous membranes and various organs
38
What is diffuse lymphatic tissue?
Lymphocytes are scattered (not clustered)
Prevalent in body passages open to the exterior
Respiratory, digestive, urinary, and reproductive tracts
Mucosa-associated lymphatic tissue (MALT)
39
What are lymphatic nodules?
Dense masses of lymphocytes and macrophages that congregate in response to pathogens
Constant feature of the lymph nodes, tonsils, and appendix
40
What are the types of lymphatic tissue?
diffuse lymphatic tissue
lymphatic nodules
peyer patches
41
What is a peyer patch?
dense clusters of lymphocytes in the ileum, the distal portion of the small intestine
42
How are lymphatic organs anatomically defined?
By the connective tissue capsule that separates the lymphatic tissue from neighbouring organs
43
Which are the primary lymphatic organs?
Red Bone marrow and thymus
44
What happens in the primary lymphatic organs?
T and B cells become immunocompetent: able to recognize and respond to antigens
45
Which are the secondary lymphatic organs?
Lymph nodes, tonsils and spleen
46
Where do all lymphocytes originate?
Red bone marrow
47
What happens in the secondary lymphatic organs?
Immunocompetent cells populate the tissues
48
Which organ systems does the Thymus belong to?
endocrine, lymphatic and immune
49
Reticular epithelial cells seal off cortex from the medulla forming which barrier?
Blood Thymus Barrier
50
What are the functions of the Thymus in the lymphatic system?
Houses developing lymphocytes
secretes hormones, regulating their activity
51
which signalling molecules does the Thymus produce?
interleukins
Interferon
thymosin
thymopoietin
thymulin
52
How many lymph nodes does the average young adult have?
450
53
What are the functions of the lymph nodes?
Cleanse the lymph
Act as a site of T and B cell activation.
54
What occurs in the the Germinal center?
B cells multiply and differentiate into plasma cells
55
Describe the anatomy of a lymph node
Elongated, bean-shaped structure with hilum
Enclosed with fibrous capsule with trabeculae that divide interior into compartments
Stroma of reticular fibers and reticular cells
56
What is the function of afferent lymph vessels?
Bring lymph into the node along its convex surface
57
How many efferent vessels are on a lymphatic node?
1-3
58
What is the function of efferent lymphatic vessels?
Lymph leaves the node through these
59
Which lymph nodes are especially concentrated within the body?
Cervical lymph nodes
Axillary lymph nodes
Thoracic lymph nodes
Abdominal lymph nodes
Intestinal and mesenteric lymph nodes
Inguinal lymph nodes
Popliteal lymph nodes
60
Where do you find cervical lymph nodes and what is their function?
in deep and superficial groups in the neck,
monitor lymph coming from the head and neck.
61
Where do you find axillary lymph nodes and what is their function?
in the armpit (axilla)
receive lymph from the upper limb and breast.
62
Where do you find thoracic lymph nodes and what is their function?
in the thoracic cavity, mediastinum,
receive lymph from the mediastinum, lungs, and airway.
63
Where do you find Abdominal lymph nodes and what is their function?
in the posterior abdominopelvic wall
receive lymph from the urinary and reproductive systems.
64
Where do you find Intestinal and mesenteric lymph nodes and what is their function?
in the mesenteries and adjacent to the appendix and intestines;
they receive lymph from the digestive tract.
65
Where do you find Inguinal lymph nodes and what is their function?
in the groin
receive lymph from the entire lower limb.
66
Where do you find popliteal lymph nodes and what is their function?
at the back of the knee
receive lymph from the leg proper.
67
What is Lymphadenitis?
swollen, painful node responding to foreign antigen
68
What is Lymphadenopathy?
collective term for all lymph node diseases
69
what is a Metastasis of cancer?
cancerous cells break free from original tumor, travel to other sites in the body, and establish new tumors
70
What is the typical path of metastasized cancer cells through the lymph nodes?
Metastasizing cells easily enter lymphatic vessels
Tend to lodge in the first lymph node they encounter
Multiply there and eventually destroy the node
Tend to spread to the next node downstream
71
What are tonsils?
patches of lymphatic tissue located at the entrance to the pharynx
Covered with epithelium
Have deep pits: tonsillar crypts lined with lymphatic nodules
72
What is the main function of tonsils?
Guard against ingested or inhaled pathogens
73
What is Tonsillitis?
Acute Inflammation due to Strep infection
74
What is a Tonsillectomy?
Surgical removal of the tonsils
75
Name the three sets of tonsils
Palatine tonsils
Lingual tonsils
Pharyngeal tonsils (adenoids)
76
Where are the Palatine tonsils located?
At posterior margin of oral cavity
77
Where are the Lingual tonsils located?
at root of tongue
78
Where are the Pharyngeal tonsils (adenoids) located?
Single tonsil on wall of nasopharynx
79
What is the largest lymphatic organ?
The spleen
80
What are the two types of parenchyma of the spleen?
```
Red pulp (erythrocytes)
White pulp (lymphocytes, macrophages)
```
81
What are the functions of the spleen?
Healthy RBCs come and go
RBC graveyard
Blood cell production in fetus
White pulp monitors blood for foreign Ags and keeps an army of monocytes for release when needed
Stabilizes blood volume through plasma transfers to lymphatic system
82
What are the two types of immune response?
Non-specific (innate)
Specific (immune system)
83
What are the bodies' 3 lines of defenses against pathogens?
1: skin and mucous membranes
2: several nonspecific defense mechanisms
3: the immune system
(Defeats a pathogen, and leaves the body with a “memory” of it so it can defeat it faster in the future)
84
What is the function of Nonspecific defenses?
guard equally against a broad range of pathogens
They lack capacity to remember pathogens
85
What are the 3 kinds of nonspecific defenses?
Protective proteins
Protective cells
Protective processes
86
What is Specific or adaptive immunity?
body must develop separate immunity (memory) to each pathogen
Body adapts to a pathogen and wards it off more easily upon future exposure
87
Name the external barriers of the non-specific immune system
skin
acid mantle
peptides in skin
mucus membranes
lysosymes
88
what is the acid mantle?
thin film of lactic and fatty acids from sweat and sebum that inhibits bacterial growth
89
Name the peptides in the skin that kill microbes
Dermicidin, defensins, and cathelicidins
90
Where are the mucus membranes located?
Digestive, respiratory, urinary, and reproductive tracts
91
What are the 5 types of leukocytes?
Neutrophils
Eosinophils
Basophils
Monocytes
Lymphocytes
92
What are phagocytes?
cells that engulf foreign matter
93
What is the function of neutrophils?
Wander in connective tissue killing bacteria
Can kill using phagocytosis and digestion
94
What is the function of eosinophils?
Found especially in mucous membranes
Guard against parasites, allergens
95
What are mast cells?
Type of connective tissue cell very similar to basophils
96
What is the function of basophils?
Secrete chemicals that aid mobility and action of other leukocytes
Leukotrienes
Histamine
Heparin
97
What are the three categories of lymphocytes?
T cells, B cells, NK cells
98
What is the function of Monocytes?
emigrate from blood in to connective tissue and transform in to macrophages.
99
What are the two types of Macrophages?
Wandering macrophages: actively seek pathogens
Fixed macrophages: phagocytize only pathogens that come to them:
100
Where do you find microglia?
in CNS
101
Where do you find alveolar macrophages?
in lungs
102
Where do you find hepatic microphages?
in liver
103
What are antimicrobial proteins?
Proteins that inhibit microbial reproduction and provide short-term, nonspecific resistance to pathogenic bacteria and viruses
104
What are the two types of antimicrobial proteins?
Interferons
Complement system
105
What is the function of interferons?
Alert neighboring cells and protect them from becoming infected
Bind to surface receptors on neighboring cells
Activate 2nd-messenger systems within
The alerted cell synthesizes various proteins that defend it from infection
Also activates NK cells and macrophages
106
What is the complement system?
a group of 30 or more globular proteins that make powerful contributions to both nonspecific resistance and adaptive immunity
107
What are the four methods of pathogen destrtuction in a complement system?
Inflammation
Immune clearance
Phagocytosis
Cytolysis
108
what are the 3 routes of complement activation?
Classical pathway
Alternative pathway
Lectin pathway
109
Which complement pathway is antibody dependant?
Classical pathway
110
Which complement pathways are not antibody dependant?
Alternative pathway
Lectin pathway
111
Where do all complement pathways merge?
The point at which C3 is activated
112
Which mechanism results from the C3a path?
inflammation
113
Which mechanisms result from the C3b path?
Immune clearance
Phagocytosis
Cytolysis
114
What is the membrane attack complex?
Complement proteins form ring in plasma membrane of target cell causing cytolysis
115
How does the membrane attack complex destroy a cell?
The complex forms a hole in the target cell
electrolytes leak out, water flows rapidly in, and the cell ruptures.
(Cytolysis)
116
Are NK cells stationary or mobile cells?
Mobile. they continually patrol body looking for pathogens and diseased host cells
117
How do NK cells kill pathogenic cells?
Recognize enemy cell and bind to it
Release proteins called perforins
Secrete a group of protein-degrading enzymes—granzymes
Enter through pore and degrade cellular enzymes and induce apoptosis (programmed cell death)
118
What are antipyretics?
fever-reducing medications (aspirin)
119
How does fever aid the adaptive immune response?
Promotes interferon activity
Elevates metabolic rate and accelerates tissue repair
Inhibits reproduction of bacteria and viruses
120
What are the stages of fever?
onset
stadium
effervescence
121
what is apoptosis?
programmed cell death
122
What is inflammation?
local defense response to a tissue injury caused by trauma or infection
123
What is the function of inflammation?
Limits spread of pathogens, then destroys them
Removes debris from damaged tissue
Initiates tissue repair
124
What are the 4 signs of inflammation?
redness
swelling
heat
pain
125
Name the 5 steps of an inflammatory reaction
1. release of inflammatory chemicals
2. margination
3. diapedesis
4. chemotaxis
5. phagocytosis
126
Which inflammatory chemical is released in an inflammatory reaction?
Histamine
127
What are the three sources of inflammatory chemicals?
Basophils
mast cells
blood plasma
128
What is leukocyte margination?
adhesion of a leukocyte to the capillary wall
129
What is diapedesis?
Process of a leukocyte crawling through the wall of a capillary
130
What is chemotaxis?
movement of a leukocyte towards inflammatory chemicals
131
What are the two distinguishing characteristics of the adaptive immune system?
Specificity
Memory
132
What do we mean by specificity in the immune system?
immunity directed against a particular pathogen
133
What do we mean by memory in the immune system?
when re-exposed to the same pathogen, the body reacts so quickly there is no noticeable illness
134
What are the two types of adaptive immunity?
Cellular, cell mediated
Humoral, antibody mediated
135
How does cellular immunity work?
Lymphocytes directly attack and destroy foreign cells or diseased host cells
Rids the body of pathogens
Kills cells that harbor them
136
How does Humoral immunity work?
Mediated by antibodies (Abs) that tag pathogens for destruction
Many Abs are dissolved in body fluids (“humors”)
Can only work against the extracellular stages of infections by microorganisms
137
What is Natural active immunity?
Production of one’s own Abs or T cells as a result of infection or natural exposure to antigen (Ag)
138
What is Artificial active immunity?
Production of one’s own Abs or T cells as a result of vaccination against disease
139
What is Natural passive immunity ?
Temporary immunity that results from Abs produced by another person (Fetus acquires Abs from mother through placenta, milk)
140
What is Artificial passive immunity?
Temporary immunity that results from the injection of immune serum (Abs) from another person or animal
Treatment for snakebite, botulism, rabies, tetanus, and other diseases
141
What is an antigen?
any molecule that triggers an immune response
142
What are epitopes?
certain regions of an Ag-molecule that stimulate immune responses
143
What are haptens?
Are too small to be an antigen, but can trigger an immune response by combining with a host macromolecule and creating a complex that the body recognizes as foreign
144
Name the major cells of the immune system
Lymphocytes
macrophages
dendritic cells
145
Which cells within the thymus stimulate maturation of a T Lymphocyte?
Reticular epithelial cells (RE)
146
What do T lymphocytes have to develop to be considered mature?
surface Ag receptors (TCRs)
147
once a T lymphocyte is mature, what does it become?
immunocompetent
148
T-cells that fail the self antigen test are eliminated by what type of selection?
Negative selection
149
How can a T cell fail the self antigen test?
Failure to recognize the self antigen
reacting to the self antigen
150
What are the removal processes of negative selection?
Clonal deletion
Anergy
151
What happens to T-cells that survive negative selection in the thymus?
They undergo positive selection
152
What is the naive lymphocyte pool
immunocompetent T cells that have not yet encountered foreign antigens
153
What is lymphocyte deployment ?
Naive T cells leave thymus and colonize lymphatic tissues and organs everywhere in the body
154
Where do B Cells mature?
bone marrow
155
What are the processes of elimination for B-cells that react to self antigens?
anergy
clonal deletion
156
What is the function of self tolerant B cells?
synthesize antigen surface receptors (BCRs)
divide rapidly
produce immunocompetent clones
157
Which cells function as Antigen Presenting Cells?
Dendritic cells
macrophages
reticular cells
B cells function
158
Function of an APC depends on which protein?
major histocompatibility (MHC) complex proteins
159
What are the 6 steps of Antigen processing and presenting?
1. Phagocytosis of antigen
2. Lysosome fuses with phagosome
3. Antigen and enzyme mix in phagolysosome
4. Antigen is degraded
5. Exocytosis
6. Epitope displayed
160
What are the four types of T-cells?
Cytotoxic
Helper
Regulatory
Memory
161
What is the function of Tc (Cytotoxic T-cells)
Effectors, carry out the attack on pathogens
162
What is the function of TH (Helper T-cells)
Promote T and B cell action/ non specific resistance
163
What is the function of TR (Regulatory T-cells)
inhibit multiplication and cytokine secretion by other T cells. Limit immune response
164
What is the function of Tm (Memory T-cells)
Responsible for memory in cellular immunity
165
What are the three R's of Cellular and Humoral immunity?
Recognize
React
Remember
166
what are the steps of antigen recognition in cellular immunity?
APC encounters and processes an Ag
Migrates to nearest lymph node
Displays it to the T cells
When T cells encounter displayed antigen on the MHC protein, and initiate the immune response
167
What are the two classes of MHC proteins?
MHC I
MHC II
168
Where are MHC I proteins found?
on all nucleated cells
169
Where are MHC II proteins found?
only on APC's and displayed on foreign antigens
170
Which T-cells react to MHC I?
Tc (cytotoxic) cells
171
Which T-cells react to MHC II?
TH (helper) cells
172
What is happening at number 1?
Antigen recognition
173
What is happening at number 2?
Costimulation
174
What is happening at point 3?
clonal selection
175
What is happening at point 4 for the MHC I protein path?
T-Cells attack
176
What is happening at point 4 for the MHC II path?
Interleukin secretion
177
What is the result of the MHC I path shown in the green box?
Destruction of the enemy cell
178
What is the result of the MHC II protein path as shown in the pink box?
Activation of NK T or B cells
Inflammation and other non specific defenses
Development of memory T cells
179
which types of immunity do TH (Helper T cells) activate?
Non-specific
Humoral
Cellular
(All)
180
How do TC (Cytotoxic )cells kill foeriegn cells?
Same as NK cells
Docks to HC I protein
secretes perforin and granzymes into cell
Apoptisis occurs
181
What is the function of interferons?
inhibit viral replication
Recruit and activate macrophages
182
What is the function of Tumor Necrosis factor?
aids in macrophage activation and kills cancer cells
183
What is the functional difference between the Cellular and Humoral immune responses?
Humoral uses B cells to tag foreign cells for destruction by T cells, Cellular immunity attacks the cells directly
184
What is happening at point 1
Antigen recognition
185
What is happening at point 2
Antigen presentation
186
What is happening at point 3
Clonal selection
187
What is happning at point 4?
Differentiation
188
What is happening at point 5?
Attack
189
What is the structure labelled A?
Disulfide bonds
190
What is the structure labelled B?
Antigen binding site
191
What is the structure labelled C?
Light chain
192
What is the structure labelled D?
hinge region
193
What is the structure labelled E?
Complement binding site
194
What is the structure labelled F?
Heavy chain
195
What is the structure labelled G?
Constant regions
196
What is the structure labelled H?
Variable regions
197
What are the five classes of antibodies?
IgA
IgD
IgE
IgG
IgM
198
What are the two mechnisms by which the variety of proteins are accomplished?
Somatic recombination
Somatic hypermutation
199
What are the Antibodies 4 mechanisms of attack againts Ags?
Neutralization
Complement fixation
Agglutination
Precipitation
200
What are the two types of adaptive immune response?
Primary immune response
Secondary immune response
201
When does the primary immune response occur?
On first exposure to a pathogen
202
when does the secondary immune response occur?
when re-exposed to the same antigen
203
What are the characteristics of a primary Immune response?
Takes 3-5 days for antibodies to activate
IgM appears first and peaks after 10 days
IgG comes after
Leaves immune system with memory of the Ag
204
What are the characteristics of a Secondary immune response?
Plasma Abs form within hours not days
IgG rises sharply and peaks in a few days
Lower levels of IgM secreted and quickly decline
No illness occurs
205
What type of response does this graph show?
Primary response
206
What type of response does the graph show?
Secondary response
207
What is hypersensitivity?
an excessive immune reaction against Ags that most people tolerate
208
What is type 1 hypersensitivity?
Food allergies and Asthma
209
What is type II Hypersensitivity?
Blood transfusion reaction and Drugs
210
What is type III Hypersensitivity?
Autoimmune diseases
211
What is type IV sensitivity?
TB skin test reaction and Type I Diabetes mellitus
212
What is anaphylaxis?
–Immediate, severe type I immune reaction
213
What is an autoimmune disease?
failure of immune system to distinguish self-antigens from foreign ones. (Self tolerance)
214
What are the reasons for failure of self-tolerance?
–Cross-reactivity
–Abnormal exposure of self-Ags in the blood
–Changes in structure of self-Ags
–Not all are eliminated in thymus and are normally kept in check by regulatory T (TR) cells
215
What is an immunodeficiency Disease?
Immune system fails to react vigorously enough
216
What is the most common immunodeficiency Disease?
Severe Combined Immunodeficiency Disease (SCID)
217
What is Acquired immunodeficiency syndrome (AIDS)
– Nonhereditary disease
– severely depresses the immune response
–caused by infection with the human immunodeficiency virus (HIV)
–Invades helper T cells, macrophages, and dendritic cells
* strikes at the central coordinating agent of nonspecific defense, humoral immunity, and cellular immunity
* Incubation period several months to 12-15 years
