Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Foundations- Block 1 > Immunology > Flashcards

Immunology Flashcards

1
Q

Cells involved in innate immunity

A

Granulocytes, macrophages, dendritic cells, NK cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where are immune cells created and differentiated?

A

Bone marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Adaptive immunity cells

A

T-cells, B-cells, macrophages, dendritic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Rate of response for innate immunity and specificity

A

Fast; unspecific

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Rate of response for adaptive immunity and specificity

A

Delayed response and specific

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Lymphocytes

A

B-cell, T-cells, monocytic cells, NK cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

B-cell: location of maturation and characteristics

A

Bone marrow; Produces antibodies, B cell receptor pathogen recognition, MHC class 1 and 2 APC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Plasma cells

A

B-cells that are short lived and actively produce antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Memory cells

A

B-cells that are long living and protect against reinfection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

T-cells: location of maturation

A

thymous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Tc cell

A

Cytotoxic T cell that induces death via direct cell-cell contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

T-h cell

A

Helper T cells that release cytokines for immune modulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cytokines

A

Chemical messengers that direct the immune response

Regulatory chemical messengers that cells with surface receptors for specific cytokine types respond to

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

T-reg

A

Regulatory T cells that suppress immune response when an infection is under control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Activated T-cells

A

Effector and memory cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

NK Cell characteristics

A

Leukocyte that is part of the innate response; non-adaptive; effective in early viral infections; cytotoxic to healthy cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Perforin

A

The substance secreted by a NK cell to bore holes into another cell’s plasmalemma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Granzymes

A

Cytotoxic chemicals that enter perforins and trigger apoptosis (NK cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Phagocytic cells

A

Neutrophils and monocytic cells; eosinophils can also, but only secondary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Cytokine producers (major)

A

T-helper cells (adaptive) and macrophages (innate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Degranulation

A

Mast cells and basophils- chemical mediators

Eosinophils and neutrophilsp- cytotoxic substances

Granules released from the surface of granulocytes that trigger a response (innate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Pattern Recognition Receptors

A

Receptors used by phagocytic cells to determine what cells they will eat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Length of time a monocytic cell circulates before differentiation

A

One day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Shape of monocytic nucleus

A

C/horseshoe shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

M1 vs M2 Macrophagic functions

A

M1- cytotoxic (also to human tissue)

M2- immunosuppressant and tissue repair

Phagocytosis, antigen presentation, inflammation, and cytokine production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Plasmacytoid Dendritic Cells produce…

A

…interferons (anti-viral cytokines), and have innate functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where are conventional DCs located?

A

Peripheral tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What cell serves as the link for innate and adaptive immune response?

A

Dendritic Cells (DCs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Also known as polymorphonuclear leukocyte, this cell is the first responder in cell-mediated immunity and can use phagocytosis, degranulation, and NETs

A

Neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Horseshoe shaped nucleus with segmentation. Segmentation alterations can be indicative of deficiency of this vitamin

A

Neutrophil; Vit B12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Primary effector is degranulation, but can phagocytosis something. Parasites are usually targeted by this cell. IgE opsonizes parasites

A

Eosinophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Involved in allergic response via IgE surface receptors, granules contain histamine and herapin, and circulate in blood

A

Basophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Histamine and herapin granules, found in tissues, IgE surface receptors (high affinity), main participator in allergic response

A

Mast Cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Low WBC count can be caused by..

A

Chemotherapy, radiation therapy, lupus and lyme, HIV, steroid use

These include Monocyetes, lymphocytes, granulocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

High WBC count can be caused by..

A

Infection/chronic inflammation, and some canacers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Low lymphocyte count can be caused by..

A

(B,T,NK cells) Medications (corticosteroids), stress, intense exercise, chemo and radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

High lymphocyte count can be caused by..

A

Lymphocytosis- infections, leukemias and lymphomas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

High monocyte count…

A

Chronic inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Low monocyte count…

A

Steroids, stress, acute infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Neutrophilia/penia

A

Infection, inflammation, injury /or/ increased risk of infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the primary lymphoid organs?

A

Bone marrow, thymus, and fetal liver (not applicable for most cases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What are the secondary lymphoid organs?

A

Lymph nodes, spleen, mucosal-associated lymphoid tissue (MALT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What do the primary lymphoid organs do?

A

Site of lymphocyte production and maturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What do secondary lymphoid organs do?

A

Site of lymphocyte activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What do lymphatic vessels do?

A

Transport lymph and luekocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Where are lymphocytes all produced?

A

Bone Marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Where do B-cells, NK cells, and T-cells mature?

A

Bone marrow and thymus, respectively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

How does the thymus respond to aging?

A

Replacement of active tissue with fat; basically, it shrinks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

How can the thymus cortex be identified histologically? What does it predominantly contain?

A

Darker staining compared to medulla; T-cell rich

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

How can the Thymus medulla be visualized via staining? What leukocytes is this component rich in?

A

Lighter staining; antigen presenting cells and macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is the function of the hassall’s corpuscules?

A

Nobody really knows

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is the progenator of T-cells?

A

thymocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

About how many lymph nodes are in the body?q

A

500-700

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What lymphocytes are primarily contained in the primary lymphoid follicle of a lymph node?

A

B-cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What lymphocyte(s) is most abundant in the parafollicular cortex of a lymph node?

A

T-cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

How is lymph circulated in the body?

A

Muscular contractions and one-way valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What are swollen lymph nodes indicative of?

A

Active viral or bacterial infection; OR blockage following an infection that is benign in nature

Secondary swelling concerns: cancer, arthritis, and allergic reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What is the primary function of the spleen? What is the secondary function of the spleen?

A

1*: filter and discard/recycle red blood cells

2*: Halting circulatory pathogens while filtering blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

The red pulp of the spleen acts to…

A

…phagocytose worn out RBCs and components and antigens/microbes in the blood stream

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

The white pulp of the spleen is…

A

..areas of lymphocytes around arterioles. (There is some separation of B and T cell areas)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What does PALS stand for? What does it do?(Spleen)

A

PeriArteriolar Lymphoid Sheath; contains WBC to filter blood and stop circulatory pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What secondary lymphoid organs and tissues encounter more pathogens and thus require mucosa to deter infection?

A

GI tract, respiratory system, urogenital system, and salivary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What are the organized uncapsulated lymph nodes in the gut?

A

Peyer’s patches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What areas are lymph nodes NOT found?

A

Cartilege, CNS, cornea, epidermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

T or F: Lymphatic vessels and the blood stream are independent of one another

A

FALSE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Where do lymph vessels enter the blood stream?

A

Thoracic duct and cisterna chyli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What are the weak cell adhesion molecules present on lymphocytes?

A

Selectins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What are the strong cell adhesion molecules on lymphocytes?

A

Integrins

69
Q

What is the movement of blood cells trough an unruptured vessel wall into the surrounding tissue?

A

Extravasation

70
Q

What upregulates the production of integrins on a WBC?

A

Inflammatory mediators

71
Q

Where do lymphocytes enter the blood stream?

A

thoracic duct and lymphatics

72
Q

Where do lymphocytes re-enter lymph nodes?

A

High endothelial venules

73
Q

Where do lymphocytes enter and exit the spleen?

A

Blood vessels

74
Q

OG Definition: Any substance that could induce the generation of antibodies

Current Def: Any molecule that can bind specifically to an antibody or to antigen receptors on the cells of the immune system

A

Antigens (or self antigens in case of autoimmunity

75
Q

Antigens can be composed of…

A

Proteins, carbs, lipids, nucleic acids, or any combo of these

76
Q

What are epitopes?

A

The smallest unit of an antigen that is recognized by antibodies/antigen receptors

77
Q

What molecules are commonly have multivalent epitomes?

A

Carbohydrates with repeating monosaccharide unites

78
Q

What molecules are commonly polyvalent epitopes?

A

Proteins

79
Q

What are conformational epitopes? Where are they found?

A

3-D structure of epitopes usually found in the native structure of the epitope (no alteration)

80
Q

What are linear epitopes? Why/How do they exist?

A

Denatured structure of conformational epitopes

81
Q

What immune structures recognize conformational epitopes?

A

Antibodies, B-cell receptors, Innate receptors

82
Q

What immune structures present and recognize linear epitopes?

A

Presented by: MHC and recognized by T-cell receptors

Subscript: can also be recognized by B cell/antibody/innate receptors

83
Q

How many antibody types can one B-cell produce?

A

ONE

84
Q

What antibody types are typically stimulatory of immune generation when they bind to an antigen?

A

Immunogens

85
Q

What antibody type cannot induce immune response without being bound to a carrier molecule first?

A

Haptens

86
Q

What antibody type can bind and induce an immune response, but this response decreases with subsequent exposure?

A

Tolerogens

87
Q

What antibody type can induce non-specific division and differentiation of leukocytes?

A

Mitogens (think MITosis)

88
Q

What is mixed with antigens to increase the immunogenicity of the bound antigen? What is this commonly used for?

A

Adjuvants; vaccine boost of immune response and memory cell increase

89
Q

What type of antigen receptors do the innate immune system use?

A

Pattern Recognition Receptors (PRRs)

90
Q

What type of antigen receptors are used primarily by the adaptive immune system?

A

Antigen specific receptors (BCR and TCR for B and T cells respectively)

91
Q

What antigen presentation can the TCR ONLY see?

A

MHC-presented antigens

92
Q

What word best describes the adaptive immune response?

A

Discriminatory

93
Q

What word best describes the innate immune response?

A

General/ Unspecific

94
Q

What do PRRs recognize on antigen cells?

A

PAMPs (pathogen-Associated Molecular Patterns)

95
Q

Unprocessed antigens are recognized by which antigen receptor and immune cell? What of the two types can this receptor recognize?

A

BCR/B-cells; Linear and conformational epitopes

96
Q

What cell and receptor recognizes processed peptides presented by MHC? What classifications is this epitope?

A

T-cell/TCR; linear epitopes

97
Q

Are cytokines stored in the cell or synthesized directly prior to release?

A

Synthesized prior to release

98
Q

Where on a cytokine response able cell is the receptor located?

A

Surface of cell

99
Q

Is a cytokine surface receptor specific to a type of cytokine or general to all cytokines?

A

General

100
Q

What are the five classes of cytokines?

A

Interferon, interleukin, chemokine, TNF-alpha, and Growth Factors

101
Q

What two immune cells excel at cytokine production

A

Macrophages and CD4+ T cells

102
Q

What immune responses are regulated by cytokines, innate or adaptive?

A

Both

103
Q

Can one cytokine produce different immune results depending on the immune cell it acts on?

A

Yes. IE: B-cells can be stimulated to produce IgE, CD4+ cells can be stimulated to enact Tm2 production, and Macrophages can be inhibited all by the same cytokine type.

104
Q

Can multiple different cytokines illicit the same response on certain immune cells?

A

Yes. IE: IL-2,4,5 can cause a B-cell to proliferate

105
Q

Can different cytokines be synergistic, both binding to one cell to increase the response strength?

A

Yes

106
Q

Can different cytokines be antagonistic?

A

Yes

107
Q

What are the most important cytokines in the acute inflammation response?

A

IL-1, IL-6, and TNF-alpha

108
Q

What is the type 1 interferon (INF) mechanism?

A

1) binds to cell surface
2) triggers RNAse
3) RNAse lyses viral RNA prior to translation
4) viral replication stopped

109
Q

What cells secrete INF-gamma?

A

T-cells and NK cells

110
Q

What does INF-gamma do?

A

1) increase microbicidal activity of macrophages
2) Increase cytotoxic activity of NK cells
3) stimulates antibody production from B-cells

111
Q

What two complementary pathways are identical after the initial step?

A

Lectin and Classical

112
Q

What complement proteins trigger inflammatory response?

A

C3a and C5a (also C4a)

113
Q

What triggers the alternate complement pathway?

A

Random encountering of C3b to microbes

114
Q

What triggers the classical complement pathway?

A

Attachment of IgG to a microbe, then binding of C1 to Fc on IgG

115
Q

What initiates the lectin complement pathway?

A

Binding of mannose-binding lectin to a microbe

116
Q

What does Factor D do in the complement pathway?

A

Cleaves Factor B to Ba and Bb

117
Q

What activates C4 and C2 in the classical/lectin pathways?

A

C1r/s

118
Q

What are the components of the MAC?

A

C5b, C6-9

119
Q

What microbes are susceptible to MAC?

A

Those with thinner cellular membranes or no glycocalyx

120
Q

What molecule of the complement pathway is an opsonin? What does this do?

A

C3b; CR-1 expressed on phagocytes recognizes this and induces phagocytosis

121
Q

What complement proteins are chemotaxic for neutrophils? What else do they do?

A

C3a and C5a; also induces inflammation; also stimulates movement of plasma proteins and leukocytes into the tissue

122
Q

What does a C3 deficiency lead to?

A

Increased susceptibility to bacterial infections, lower complement action

123
Q

What does C2&4 deficiency result in?

A

No consequence, increased infection susceptibility, or induce lupus incidence (unsure)

124
Q

What inhibitors regulate the complement pathway?

A

C1 INH, DAF (Decay Accelerating Factor), Cofactors Factor H and I

125
Q

What does a deficiency of C1INH cause?

A

Buildup of inflammation, increased complement activity, fluid leakage into ISF (edema)

126
Q

What does a deficiency of DAF induce?

A

Unchecked complement activity and RBC lysis

127
Q

What does a deficiency of Factor I and H do?

A

Increased complement activity, but lower C3 levels due to less C3b

128
Q

What cells produce immunoglobulins?

A

B-cell

129
Q

What are the two major functions of antibodies?

A

1) Specifically bind to a pathogen

2) Recruitment of cells and molecules to destroy pathogen

130
Q

What are the two basic structural components of antibodies?

A

Heavy and Light chain (both contribute to binding site)

131
Q

What is Fab and Fc on an antibody?

A 
Fab= fragment antigen binding
Fc= Fragment crystallizable (Fc effector binds to various cell receptors and complement)
132
Q

What kind of bond do antibodies form to conformational epitopes?

A

Non-covalent

133
Q

What is an epitope?

A

The part of an antigen that is recognized by the immune system

134
Q

What types of antigens can be bound to by antibodies and illicit an immune response?

A

Immunogen, Haspten, and Autoantigen

135
Q

What is combinatorial diversity of antibodies?

A

Generating a large number of combinations of the VDJ segments to create antibodies that can bind to pathogens without encountering first

136
Q

What is the valence of a monomer immunoglobulin?

A

2

137
Q

What creates junctional diversity in antibodies?

A

Addns, deletions at nucleotide junctions during recombination

138
Q

What is the antibody affinity and avidity?

A

Affinity=binding strength at a single site

Avidity= summative binding str of all sites

139
Q

What is Omenn Syndrome? What cells are affected?

A

It is Auto Recess mutation of RAG enzymes; B/Tcells low counts

Characterized by failure to thrive, erythroderma, diarrhea, immunodefic.

140
Q

What is SCID? How is this different than Omenn Syndrome?

A

NO RAG activity or B/T cells; auto-recessive null mutations in RAG gene

Signs: Interstitial lung disease, diarrhea, severe infections, fail to thrive

141
Q

What determines the antibody class (isotope) and antibody function (broad scale)?

A

Heavy chains: mu, gamma, sigma, alpha, and epsilon

142
Q

Do changes in light chains result in different functions? What is the normal kappa:lambda ratio of light chains? What can variations of this ratio indicate?

A

No; 60:40; B-cell cancer

143
Q

What are expressed as BCR? What do naive, mature B cells express? Memory B-cell expression?

A

Immunoglobulins; IgD and IgM; any isotype as BCR

144
Q

What triggers B-cell activation? Clonal expansion? Antibody production?

A

BCR binding to an antigen; all create variable antibodies; plasma cells create antigen-specific antibodies based on what the BCR is bound to

145
Q

What structural component in Ig determines free form or membrane bound?

A

Transmembrane anchor on the heavy chain

146
Q

What are the five functions of antibodies?

A

Neutralization, complement activation, opsonization, antibody-dependent cell-mediated cytotoxicity (ADCC), mast cell degranulation

147
Q

What function does secreted IgG (subtypes in blood/tissues) and dimeric IgA perform?

A

Neutralization

148
Q

What Ig can trigger the complement pathway?

A

IgM (pentamer) or 2 IgG

149
Q

Fc receptors on what molecules recognize antibodies on pathogens to induce phagocytosis? What antibody is recognized? What is this antibody function called?

A

Phagocytes; IgG; opsonization

150
Q

What immune cell is activated via ADCC? How do antibodies recognize virally infected cells? What receptors on the effector cell (first Q) recognize these antibodies?

A

NK cells; they bind to viral proteins on the surface of virally infected cells; Fc receptors (specifically CDD16 or Fc-gamma-RIIIA)

151
Q

What antibody is recognized by mast cells via the Fc-epsilon-R receptor to induce allergic response?>

A

IgE

152
Q

What antibody opsonizes parasites? What does an IgE-coated parasite stimulate eosinophils to do?

A

IgE; degranulate then phagocyte the resulting parasitic debris

153
Q

What granules are released from eosinophils?

A

Major basic protein (MBP); Eosinophil cationic protein (ECP), and eosinophil peroxidase (EPO)

154
Q

What isoform is IgM secreted as? Membrane-bound as? What can this antibody do?

A

Pentamer; monomer; activate complement pathway (classical)

155
Q

What is the general valence of IgM? What causes the IgM to be transported across epithelium?

A

Valence=10; J-chain

156
Q

What syndrome is associated with elevated IgM levels, decreased presence of other isotypes, and presents in children via recurrent resp infections?

A

X-linked Hyper IgM syndrome

157
Q

What is the function of IgD? Where can they be mostly found?

A

Unknown; upper respiratory tract

158
Q

What antibody is 80% of the serum’s antibody?

A

IgG

159
Q

What antibody notably crosses the placenta?

A

IgG

160
Q

What are the four main functions of IgG?

A

Neutralization, Opsonization, Complement activation, and ADCC

161
Q

What immunoglobulin is secreted as a monomer, less than 1% of serum Ab, and has a major role in allergic and parasitic response?

A

IgE

162
Q

What is the antibiotic that has a common allergy response? What Ig is responsible? What is the biochemical structure that reacts with the antibody?

A

Penicillin; IgE; beta-lactim rings (PCN, cephalosporins, carbapenems)

163
Q

What Ig is a monomer in blood and a dimer in secretions/mucous?

A

IgA

164
Q

What antibody is the primary class in secretory/mucosal?

A

IgA (breast milk, tears, saliva)

165
Q

IgA binds to polymeric-Ig receptor to pass through what?

A

Epithelial cells

166
Q

Antibody deficiencies result in which characteristic infections?

A

Recurrent pyogenic infections, encapsulated bact infections, repiratory infections, and enteritis

167
Q

What are some ways pathogens can bypass antibodies?

A

Antigenic variation (modification of surface antigens/epitopes to prevent binding)

Encapsulation (hyaluronic acid capsules act as “slippery” to antibodies, difficulty binding)

168
Q

What are the three main antigen presenting cells (APC)? What do they do?

A

Dendritic cells, macrophages, B-cells; present antigens to T-cells

Foundations- Block 1 (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions