p.9
Thymus and T-cell Maturation
What percentage of T cells survive the selection process?
Only 2% of cells survive.
p.15
Spleen: Structure and Role in Immunity
What types of cells are rich in the splenic cords?
Macrophages and lymphocytes.
p.2
Cytokines and Their Functions
Which cytokines are involved in the stimulation of inflammation and fever?
TNF-α, TGF-β, and IL-1 are involved in the stimulation of inflammation and fever.
p.5
Antigens and Antibodies
What is the function of CD8 markers?
They are found on Cytotoxic T-cells and are involved in cell-mediated immunity.
p.8
Thymus and T-cell Maturation
What is the role of antigen-presenting cells in the thymus?
They form a sheetlike structure creating a corticomedullary barrier between the cortex and medulla.
p.2
Cytokines and Their Functions
How does the immune system communicate with each other?
The immune system communicates with each other through cytokines.
p.2
Cytokines and Their Functions
What is the role of GM-CSF and M-CSF?
GM-CSF and M-CSF are growth and differentiation factors for leukocyte progenitor cells in bone marrow.
p.12
Lymph Nodes: Anatomy and Immune Response
What is the function of the subscapular sinus in the cortex?
It receives lymph fluid from afferent lymphatics.
p.15
Spleen: Structure and Role in Immunity
What is the role of stave cells in the spleen?
They filter blood and allow plasma and blood to reenter the vasculature via narrow slits into the sinusoids.
p.9
Thymus and T-cell Maturation
What is the goal of the negative selection process in T-cell maturation?
The goal is for T cells to recognize self-antigens on dendritic cells but not react with them.
p.8
Thymus and T-cell Maturation
What are Hassal corpuscles and where are they found?
Hassal corpuscles are concentrically arranged large aggregates of TECs that appear as 'onion skin' with a whirling pattern, unique to the medulla of the thymus.
p.2
Cytokines and Their Functions
What are chemokines?
Chemokines are cytokines that produce the effect of chemotaxis.
p.5
Antigens and Antibodies
What is the function of CD4 markers?
They are found on Helper T-cells and are involved in recognizing antigens presented with MHC molecules.
p.12
Lymph Nodes: Anatomy and Immune Response
What are medullary cords?
Lymphoid tissue extending from the paracortex and branching into cord-like masses.
p.4
Types of Immune Defense: Innate and Adaptive
What is the role of NK cells in the immune response?
NK cells perform non-specific killing of infected cells by secreting perforin and granzymes, which cause apoptosis.
p.1
Types of Immune Defense: Innate and Adaptive
What are the main cells involved in the innate immune response?
Leukocytes, mostly granulocytes, specifically neutrophils.
p.4
Antigens and Antibodies
Which cells produce and expose MHC Class II proteins?
Cells of the mononuclear phagocyte system and certain other cells under some conditions.
p.6
Types of Immune Defense: Innate and Adaptive
What is the primary function of Regulatory T-cells?
To suppress specific immune responses and maintain immune tolerance.
p.2
Cytokines and Their Functions
Name a function of interleukins.
Interleukins are involved in the stimulation or suppression of lymphocyte activities.
p.12
Lymph Nodes: Anatomy and Immune Response
What structures are present in the cortex of lymph nodes?
Subscapular sinus and lymphoid nodules.
p.15
Spleen: Structure and Role in Immunity
What are stave cells?
Specialized endothelial cells.
p.12
Lymph Nodes: Anatomy and Immune Response
What structures are found in the medulla of lymph nodes?
Medullary cords and medullary sinuses.
p.8
Cytokines and Their Functions
What is the function of cytokines secreted by the medulla of the thymus?
These cytokines control the activity of local dendritic cells and promote the development of regulatory T cells.
p.5
Lymph Nodes: Anatomy and Immune Response
Where do mature B-cells and T-cells go after maturation?
To the secondary lymphoid organs, such as lymph nodes.
p.2
Antigens and Antibodies
What is an antigen?
An antigen is a molecule recognized by adaptive immune cells, consisting of soluble molecules or molecules of intact cells.
p.12
Lymph Nodes: Anatomy and Immune Response
What is the capsule in the lymph node?
Dense connective tissue surrounding the lymph node.
p.9
Thymus and T-cell Maturation
What determines the type of T cell a maturing T cell will become?
The CD markers that are retained in the T cell.
p.12
Lymph Nodes: Anatomy and Immune Response
What cells make up the lymphoid nodules in the cortex?
T helper cells and proliferating B cells.
p.15
Spleen: Structure and Role in Immunity
What happens to old red blood cells (RBCs) in the spleen?
They are phagocytosed by macrophages.
p.8
Thymus and T-cell Maturation
Describe the appearance of thymic epithelial cells (TECs) compared to lymphocytes.
TECs are slightly larger, almost twice the size of lymphocytes, with a centrally located nucleus and lighter stained cytoplasm. Lymphocytes have a large, rounded nucleus and scanty, purplish cytoplasm.
p.5
Antigens and Antibodies
What do the receptors on T-cells contain?
Alpha and beta chains that recognize antigens presented with MHC molecules.
p.10
Mucosa-Associated Lymphoid Tissue (MALT)
Where are lingual tonsils located?
At the base of the tongue.
p.5
Types of Immune Defense: Innate and Adaptive
What is the function of Memory T-cells?
They induce a faster response in case of subsequent exposure to the same antigen.
p.12
Lymph Nodes: Anatomy and Immune Response
What happens to lymph when it enters the subscapular sinus?
Lymphocytes process its contents.
p.10
Mucosa-Associated Lymphoid Tissue (MALT)
What is the function of M cells in Peyer's patches?
To sample antigens from the intestinal lumen and transfer them to immune cell pockets.
p.2
Cytokines and Their Functions
What are cytokines?
Cytokines are a diverse group of peptides and glycoproteins found within lymphoid organs during inflammation caused by infection or tissue injury.
p.12
Lymph Nodes: Anatomy and Immune Response
What are the three major regions of lymph nodes?
Cortex, Paracortex, and Medulla.
p.15
Spleen: Structure and Role in Immunity
Describe the process of closed circulation in the spleen.
Capillaries branching from the penicillar arterioles connect directly to the sinusoids, blood is always enclosed by endothelium, and the flow is: Trabecular artery → Central arteriole → Sinusoids → Red pulp veins → Trabecular vein.
p.2
Antigens and Antibodies
What are epitopes?
Epitopes are small molecular domains of the antigen that immune cells recognize and react to.
p.2
Clinical Significance of Lymphatic System Disorders
What was a significant challenge during the COVID-19 pandemic?
During the COVID-19 pandemic, there was a struggle between antigen and antibody testing.
p.12
Lymph Nodes: Anatomy and Immune Response
What are medullary sinuses?
Dilated spaces lined by discontinuous endothelium separating the cords.
p.4
Antigens and Antibodies
What does MHC stand for and what are its two key types?
MHC stands for Major Histocompatibility Complex, and its two key types are Class I and Class II.
p.8
Thymus and T-cell Maturation
What is the primary function of the thymus in T-cell maturation?
The thymus is the site of lymphocyte differentiation and selective removal of T cells reactive against self-antigens, inducing central self-tolerance.
p.9
Mucosa-Associated Lymphoid Tissue (MALT)
What is Mucosa-Associated Lymphoid Tissue (MALT)?
It is lymphoid tissue in the inner lining of the digestive, respiratory, or genitourinary tract that protects against pathogens.
p.15
Spleen: Structure and Role in Immunity
What are the two main components of the splenic red pulp?
Sinusoids (S) and splenic cords (C).
p.15
Spleen: Structure and Role in Immunity
What is the difference between white pulp and red pulp in the spleen?
White pulp appears as lighter areas, while red pulp is the darker area surrounding the white pulp.
p.15
Spleen: Structure and Role in Immunity
Describe the process of open circulation in the spleen.
Blood is dumped into the stroma of splenic cords, plasma and blood must reenter the vasculature via narrow slits between stave cells into the sinusoids.
p.2
Antigens and Antibodies
What is the difference between cellular and humoral immune responses?
Cellular immune response involves T lymphocytes eliminating the antigen, while humoral immune response involves antibodies primarily responsible for the response.
p.5
Antigens and Antibodies
What do T-cells require to react with antigens?
MHC molecules and either CD4 or CD8 markers.
p.8
Thymus and T-cell Maturation
How do mature T lymphocytes exit the thymus?
They pass through the walls of the venules and efferent lymphatics in the medulla region.
p.10
Mucosa-Associated Lymphoid Tissue (MALT)
What type of epithelium lines the pharyngeal tonsils?
Pseudostratified ciliated columnar epithelium.
p.4
Types of Immune Defense: Innate and Adaptive
What is the role of antigen-presenting cells (APCs) in adaptive immunity?
APCs present antigens to T helper cells, which then recruit other immune cells to fight the foreign body.
p.3
Antigens and Antibodies
Where can antibodies accumulate?
In blood plasma and interstitial fluid of tissue or transported across epithelia into the secretion of glands.
p.1
Lymphoid Organs: Structure and Function
What are the secondary lymphoid organs?
Lymph nodes, spleen, and Mucosa-Associated Lymphoid Tissue (MALT).
p.5
Overview of the Immune System
Where do all lymphocytes originate from?
Stem cells of the red bone marrow.
p.4
Cytokines and Their Functions
What is the role of Fc portions in the immune system?
Fc portions bind receptors that affect/optimize innate immunity.
p.12
Lymph Nodes: Anatomy and Immune Response
What is the role of high endothelial venules in the paracortex?
They serve as entry points for lymphocytes into lymph nodes.
p.10
Mucosa-Associated Lymphoid Tissue (MALT)
Where is the stratified squamous epithelial lining found in the lymphatic system?
In the posterior soft palate.
p.12
Lymph Nodes: Anatomy and Immune Response
What are secondary lymphoid nodules composed of?
Germinal center and mantle.
p.11
Mucosa-Associated Lymphoid Tissue (MALT)
What are the histological characteristics of the lymphoid tissues in the appendix?
Lymphoid tissues contain multiple lymphoid nodules, primary and secondary lymphoid follicles, and mantle (dark-stained) and germinal center (light-stained) are also observed.
p.10
Mucosa-Associated Lymphoid Tissue (MALT)
Describe the process of antigen recognition and response in the gut involving M cells.
Antigens are recognized by M cells and transported to intraepithelial pockets where dendritic cells process and present them to helper T cells, which then activate B lymphocytes to form antibodies.
p.3
Antigens and Antibodies
What is the variable region of an antibody?
The first 110 amino acids near the amino terminal ends of light and heavy chains that vary widely among different antibody molecules.
p.11
Lymph Nodes: Anatomy and Immune Response
What is the function of lymph nodes in the body?
Lymph nodes act as in-line filters that defend the body against the spread of microorganisms and tumor cells.
p.3
Antigens and Antibodies
What is the function of IgG antibodies?
IgG antibodies reflect a chronic or recovering response from the body and confer passive immunity against certain infections until the newborn’s adaptive immune system is acquired.
p.14
Spleen: Structure and Role in Immunity
What are the two main components of the splenic pulp?
The two main components of the splenic pulp are the white pulp and the red pulp.
p.14
Spleen: Structure and Role in Immunity
What does the white pulp consist of?
The white pulp consists of lymphoid nodules and periarteriolar lymphoid sheath (PALS).
p.6
Antigens and Antibodies
What is the result of B cell activation?
They differentiate into plasma cells producing antibodies against the antigen.
p.14
Spleen: Structure and Role in Immunity
What types of cells are found in the reticular tissue of the spleen?
The reticular tissue of the spleen contains reticular cells and fibers, lymphocytes, other blood cells, macrophages, and antigen-presenting cells (APCs).
p.5
Antigens and Antibodies
What are CD markers?
Surface proteins that allow B and T-cells to be distinguished.
p.12
Lymph Nodes: Anatomy and Immune Response
Describe the paracortex of lymph nodes.
It is the middle area with no precise boundaries or nodules, rich in T cells, and contains high endothelial venules.
p.10
Mucosa-Associated Lymphoid Tissue (MALT)
What are tonsillar crypts densely infiltrated with?
Lymphocytes and other immune cells.
p.3
Antigens and Antibodies
What is an antigen and how is it related to COVID infection?
An antigen is more specific and can indicate COVID infection earlier since it comes directly from the pathogen.
p.1
Lymphoid Organs: Structure and Function
What is the difference between primary and secondary lymphoid organs?
Primary lymphoid organs are where lymphoid lineage cells mature and become functional, while secondary lymphoid organs are where B and T cells circulate and most lymphocyte activation and proliferation occur.
p.10
Mucosa-Associated Lymphoid Tissue (MALT)
Where are Peyer's patches found?
In the mucosa and submucosa of the ileum.
p.4
Thymus and T-cell Maturation
Where do cells of lymphoid lineage mature and become functional?
In the bone marrow for B cells and in the thymus for T cells.
p.13
Lymph Nodes: Anatomy and Immune Response
How do antigens (Ags) arrive at a lymph node?
Via the afferent lymphatics.
p.10
Mucosa-Associated Lymphoid Tissue (MALT)
What is the role of plasma cells in the immune response in the gut?
Plasma cells secrete IgA antibodies that attach to antigens in the mucosa.
p.3
Antigens and Antibodies
What makes up the antigen (Ag) binding site of an antibody?
The variable portions of one heavy chain and one light chain.
p.11
Lymph Nodes: Anatomy and Immune Response
What does the lymph node filter and add before merging with the bloodstream?
Filters lymph fluid and adds lymph node antibodies.
p.13
Lymph Nodes: Anatomy and Immune Response
What is the function of B and T memory cells?
To provide long-lived protection.
p.13
Clinical Significance of Lymphatic System Disorders
What does the infiltration of cancer cells in a lymph node indicate?
That the cancer has likely spread to other parts of the body.
p.14
Spleen: Structure and Role in Immunity
What cells are primarily found in the white pulp?
The white pulp primarily contains T cells, some macrophages, dendritic cells (DCs), and plasma cells.
p.7
Thymus and T-cell Maturation
What are the two main parts of the thymus and their staining characteristics?
The cortex (outer, darkly basophilic) and the medulla (inner, lighter staining).
p.2
Cytokines and Their Functions
What is chemotaxis?
Chemotaxis is the directed cell movements toward and cell accumulation at sites of inflammation.
p.2
Cytokines and Their Functions
What is the function of IL-12?
IL-12 stimulates the growth of T lymphocytes and NK cells.
p.4
Antigens and Antibodies
What is the result of complement activation?
Cell lysis, binding and rupturing membrane-invading cells, clumping antigen-bearing bacteria, and eliciting arrival of leukocytes.
p.1
Thymus and T-cell Maturation
What is the role of the thymus in the immune system?
The thymus is responsible for the formation and differentiation of T lymphocytes.
p.5
Cytokines and Their Functions
What is the role of Helper T-cells (Th cells)?
They produce cytokines that activate B cells and Cytotoxic T-cells (CTLs).
p.1
Cytokines and Their Functions
What is the function of interferons in the immune system?
Interferons activate Natural Killer (NK) cells to kill virus-infected cells.
p.10
Clinical Significance of Lymphatic System Disorders
What is tonsillitis?
Inflammation of the tonsils.
p.11
Clinical Significance of Lymphatic System Disorders
What is appendicitis?
Appendicitis is the inflammation of the appendix.
p.3
Antigens and Antibodies
On which cells can antibodies be found?
On the surface of B-cells and leukocytes.
p.9
Mucosa-Associated Lymphoid Tissue (MALT)
What type of cells predominate in the tonsils, ileum, and appendix?
B cells predominate over T cells, specifically CD4+ helper T cells.
p.13
Lymph Nodes: Anatomy and Immune Response
What triggers the activation of lymphocytes in the lymph node?
Recognition of antigens (Ags) by their receptors.
p.14
Spleen: Structure and Role in Immunity
What is the main function of the spleen in the immune system?
The spleen is involved in blood filtration, making it an important organ in defense against blood-borne pathogens.
p.7
Lymph Nodes: Anatomy and Immune Response
What distinguishes a secondary lymphoid follicle from a primary lymphoid follicle?
A secondary lymphoid follicle has a germinal center and a mantle zone.
p.11
Lymph Nodes: Anatomy and Immune Response
What is the function of the concave depression or 'hilum' of a lymph node?
The concave depression has efferent lymphatics where lymph fluid will leave, and it also contains the vein, artery, and nerve.
p.7
Thymus and T-cell Maturation
What is the primary function of the thymus?
Producing T-cells and its subtypes.
p.7
Thymus and T-cell Maturation
What is the role of the thymus in preventing autoimmunity?
Induction of central tolerance.
p.6
Lymphoid Organs: Structure and Function
What do germinal centers make up?
The secondary lymphoid follicle.
p.4
Antigens and Antibodies
Describe the process of opsonization.
Opsonization is the binding of antibodies to a foreign body, making it more visible to immune cells and increasing phagocytosis.
p.1
Types of Immune Defense: Innate and Adaptive
Describe the function of Natural Killer (NK) cells.
NK cells destroy various unhealthy host cells, including those infected with viruses or bacteria and potentially tumorigenic cells.
p.5
Types of Immune Defense: Innate and Adaptive
What is the role of Cytotoxic T-cells (CTL)?
They are 'killer T-cells' that play a role in cell-mediated immunity.
p.12
Lymph Nodes: Anatomy and Immune Response
What is found in the medullary sinus?
Immune cells such as lymphocytes and antigen-presenting cells.
p.1
Types of Immune Defense: Innate and Adaptive
What are the components of the adaptive immune response?
B and T lymphocytes, antigen-presenting cells (APCs), and memory lymphocytes.
p.9
Mucosa-Associated Lymphoid Tissue (MALT)
What types of cells are found in MALT?
IgA secreting plasma cells, APCs, and lymphoid nodules.
p.6
Types of Immune Defense: Innate and Adaptive
Describe the first stimulation step in the activation of Helper T Lymphocytes.
CD4 binds with MHC class II molecule of APC, and TCR interacts with the antigen within the MHC Class II molecule.
p.9
Mucosa-Associated Lymphoid Tissue (MALT)
What are tonsils?
Large, irregular masses of lymphoid tissue in the mucosa of the posterior oral cavity and nasopharynx.
p.7
Lymph Nodes: Anatomy and Immune Response
What happens to naïve B-cells when activated B-cells grow rapidly?
Naïve B-cells are pushed to the side, producing the mantle.
p.1
Mucosa-Associated Lymphoid Tissue (MALT)
What is Mucosa-Associated Lymphoid Tissue (MALT) and where is it located?
MALT is immune cells located diffusely in digestive, respiratory, or urogenital mucosa.
p.6
Antigens and Antibodies
What is the role of B Lymphocytes in the immune response?
They are responsible for the humoral response.
p.14
Spleen: Structure and Role in Immunity
What percentage of the spleen does the white pulp constitute?
The white pulp constitutes 20% of the spleen.
p.11
Lymph Nodes: Anatomy and Immune Response
What specific type of cells are present within the lymphoid nodules of lymph nodes?
Follicular dendritic cells.
p.6
Lymphoid Organs: Structure and Function
What are germinal centers filled with?
Large lymphoblasts (immature B cells).
p.4
Antigens and Antibodies
What is the function of MHC Class I molecules?
MHC Class I molecules present 'self antigens' on the surface of all nucleated cells, signaling T cells to ignore those cells.
p.8
Thymus and T-cell Maturation
What is the significance of the two-stage selection process in the thymus?
It ensures that mature T cells have functional T cell receptors (TCRs) and begins in the cortex, ending in the medulla over a period of two weeks.
p.12
Lymph Nodes: Anatomy and Immune Response
Where is the subscapular sinus located in the cortex?
Between the capsule and the lymphoid nodules.
p.10
Mucosa-Associated Lymphoid Tissue (MALT)
What type of epithelium lines Peyer's patches?
Simple columnar epithelium.
p.1
Types of Immune Defense: Innate and Adaptive
What are the two main types of lymphocytes involved in adaptive immunity?
T-lymphocytes and B-lymphocytes.
p.13
Lymph Nodes: Anatomy and Immune Response
Where do B cells proliferate rapidly in the lymph node?
In the germinal centers (GC).
p.14
Spleen: Structure and Role in Immunity
Where is the spleen located in the body?
The spleen is found in the left upper quadrant of the abdomen.
p.14
Spleen: Structure and Role in Immunity
What type of tissue surrounds the spleen and penetrates its pulp?
The spleen is surrounded by a capsule from which trabeculae emerge to penetrate the splenic pulp.
p.11
Lymph Nodes: Anatomy and Immune Response
What surrounds a lymph node?
A capsule made of dense connective tissue.
p.6
Cytokines and Their Functions
What do helper T cells secrete to stimulate B cells?
IL-4 and other cytokines.
p.14
Spleen: Structure and Role in Immunity
What does the red pulp of the spleen consist of?
The red pulp consists of blood-filled sinusoids and splenic cords.
p.3
Antigens and Antibodies
What is an antibody?
A glycoprotein of the immunoglobulin family that interacts with epitopes (antigenic determinants) they recognize.
p.8
Thymus and T-cell Maturation
What happens during the positive selection stage of T-cell maturation?
Pre-T cells that can bind to MHC class 1 or class 2 molecules survive and advance to the medulla. Those that cannot bind die via apoptosis.
p.1
Types of Immune Defense: Innate and Adaptive
What is the role of memory lymphocytes in adaptive immunity?
Memory lymphocytes ensure that a similar immune response can be mounted rapidly if the invading pathogen appears again.
p.4
Lymphoid Organs: Structure and Function
What is the composition of lymphoid tissue?
Lymphoid tissue is made up of reticular connective tissue with a large number of lymphocytes, either diffuse within areas of connective tissue or surrounded by a capsule.
p.3
Antigens and Antibodies
What is the Fc region of an antibody?
The isolated carboxyl terminal portion of the heavy chain.
p.6
Types of Immune Defense: Innate and Adaptive
What is the role of IL-2 in the activation of Cytotoxic T Lymphocytes?
IL-2 released from activated helper T lymphocytes stimulates the cytotoxic T lymphocytes.
p.3
Antigens and Antibodies
How many antigen-binding sites does each antibody have?
Each antibody has 2 antigen-binding sites, both for the same antigen.
p.6
Types of Immune Defense: Innate and Adaptive
Where is the nucleus found in B Lymphocytes?
Peripherally, pushed to the side by the Golgi apparatus.
p.3
Antigens and Antibodies
Where are IgA antibodies commonly found?
In secretions such as saliva and tears.
p.3
Antigens and Antibodies
What is the role of IgE antibodies?
IgE antibodies are active in allergies and parasitic infections.
p.7
Thymus and T-cell Maturation
Describe the structure of the thymus.
It is a bilobed structure in the mediastinum with a capsulated, incomplete separate lobules.
p.6
Lymphoid Organs: Structure and Function
What happens in secondary lymphoid tissues with B cells?
They interact with Follicular Dendritic Cells (FDCs) and aggregate into primary lymphoid follicles.
p.6
Types of Immune Defense: Innate and Adaptive
What is the function of Gamma and Delta T Lymphocytes?
Their function is similar to innate immunity.
p.1
Types of Immune Defense: Innate and Adaptive
What is the function of lysozyme in the immune system?
Lysozyme hydrolyzes bacterial cell wall components, killing the cells.
p.6
Types of Immune Defense: Innate and Adaptive
Describe the first stimulation step in the activation of Cytotoxic T Lymphocytes.
CD8 binds with MHC Class I molecule of various cells, and TCR interacts with the abnormal antigen within the MHC Class I molecule.
p.7
Lymph Nodes: Anatomy and Immune Response
What is found in the germinal center of a secondary lymphoid follicle?
Lymphoblasts (e.g., immature B cells).
p.3
Antigens and Antibodies
What is known about IgD antibodies?
IgD antibodies are the least abundant, not much is known about their function, and they are found on the surface of B lymphocytes.
p.6
Antigens and Antibodies
What happens to the antigen bound to B cell receptors (BCRs)?
It is endocytosed, processed, and presented on MHC class II proteins to helper T cells.
p.3
Antigens and Antibodies
What happens during the precipitation process involving antibodies?
Precipitation occurs when a soluble antigen binds with a soluble antibody.
p.9
Mucosa-Associated Lymphoid Tissue (MALT)
Where are most immune cells in MALT dispersed?
In the connective tissue or in aggregates forming large structures like tonsils, ileum, and appendix.
p.6
Types of Immune Defense: Innate and Adaptive
What happens during the second stimulation of Helper T Lymphocytes?
Helper T lymphocytes release IL-2, which stimulates the Helper T lymphocytes.
p.1
Types of Immune Defense: Innate and Adaptive
What is the function of defensins in the immune system?
Defensins are cationic polypeptides that disrupt bacterial cell walls.
p.11
Lymph Nodes: Anatomy and Immune Response
What is the function of the convex surface of a lymph node?
The convex surface has afferent lymphatics where lymph fluid will enter.
p.13
Lymph Nodes: Anatomy and Immune Response
What cells recirculate in the efferent lymph with antibodies?
Specific Th cells, CTLs, and T regs.
p.13
Clinical Significance of Lymphatic System Disorders
What is the clinical significance of lymph nodes infiltrated by Tuberculosis?
They are enlarged and exhibit caseating necrosis, indicating tissue death and pus.
p.13
Clinical Significance of Lymphatic System Disorders
What is a common feature of lymph nodes infiltrated with melanoma cancer cells?
Their texture is similar to the features of melanoma.
p.13
Clinical Significance of Lymphatic System Disorders
What microorganism is associated with caseous necrotic tissue in lymph nodes?
Mycobacterium tuberculosis.
p.7
Thymus and T-cell Maturation
What is the function of squamous TECs in the thymus?
Forming a blood-thymic barrier to prevent unregulated exposure to antigens.
p.11
Clinical Significance of Lymphatic System Disorders
What is observed in the mucosa of an inflamed appendix under a microscope?
The mucosa is infiltrated with numerous leukocytes.
p.3
Antigens and Antibodies
Describe the basic structure of an antibody.
An antibody consists of 2 identical light chains and 2 identical heavy chains bound by disulfide bonds.
p.11
Lymph Nodes: Anatomy and Immune Response
Where are lymph nodes located?
Throughout the body along the lymphatic vessels.
p.1
Antigens and Antibodies
What is the role of antigen-presenting cells (APCs) in the immune system?
APCs present antigens to T-lymphocytes to initiate an adaptive immune response.
p.3
Antigens and Antibodies
What is the function of IgM antibodies?
IgM antibodies are the largest antibodies and are involved in the initial response to an antigen (infection). They may indicate that the patient still has an active infection.
p.3
Antigens and Antibodies
Describe the process of neutralization by antibodies.
Neutralization is when an antibody counteracts the effect of an antigen.
p.13
Clinical Significance of Lymphatic System Disorders
What does the presence of yellow areas in a lymph node specimen indicate in a patient with Tuberculosis?
Caseous necrotic tissue, commonly associated with tuberculosis.
p.14
Spleen: Structure and Role in Immunity
What are penicillar arterioles?
Penicillar arterioles are branches of central arterioles that leave the white pulp and enter the red pulp.
p.11
Lymph Nodes: Anatomy and Immune Response
Describe the shape and encapsulation of lymph nodes.
Lymph nodes are bean-shaped and encapsulated.
p.6
Types of Immune Defense: Innate and Adaptive
What is the 'rule of 8' mnemonic for T-cell activation?
CD8 x 1 = 8 and CD4 x 2 = 8, indicating CD8 is involved with MHC Class I and CD4 with MHC Class II.
p.14
Spleen: Structure and Role in Immunity
What is the typical size of the spleen?
The spleen is typically 12 × 7 × 3 cm in size.
p.6
Antigens and Antibodies
What family do B Lymphocytes involve?
The immunoglobulin family or antibodies.
p.6
Antigens and Antibodies
What is required for the activation of B cells?
The help of T helper cells.
p.11
Lymph Nodes: Anatomy and Immune Response
What types of cells are found in lymph nodes?
All types of lymphocytes, including plasma cells, dendritic cells, macrophages, and antigen-presenting cells.
p.14
Spleen: Structure and Role in Immunity
What is the function of the central arterioles in the spleen?
Central arterioles are branches of the trabecular artery surrounded by PALS and are involved in the blood supply to the white pulp.
p.7
Thymus and T-cell Maturation
What are Thymic Epithelial Cells (TECs) and their features?
TECs have features of both epithelial and reticular cells and are morphologically and functionally diverse.
p.13
Lymph Nodes: Anatomy and Immune Response
What happens to antigens (Ags) in the lymph node?
They are either phagocytosed or internalized by antigen-presenting cells (APCs) and presented on MHC class II molecules.
p.7
Lymph Nodes: Anatomy and Immune Response
Describe the primary lymphoid follicle.
It has no germinal center or mantle zone, and lymphocytes are diffusely scattered.
p.7
Lymph Nodes: Anatomy and Immune Response
What is the mantle zone in a secondary lymphoid follicle?
It is a darker staining area with smaller cells where mature cells are pushed to the side.
p.3
Antigens and Antibodies
What is agglutination in the context of antibodies?
Agglutination is the process where an insoluble antigen binds with a soluble antibody (and vice versa).
p.7
Thymus and T-cell Maturation
How does the size of the thymus change with age?
It remains large and active until puberty, then involutes and becomes smaller, with the majority of the area replaced by adipose tissue in adults.
p.7
Thymus and T-cell Maturation
What is the role of stellate TECs with cytoreticulum?
They secrete cytokines for T-cell development and other immune functions.
