Week-10-OMK

Block 2 (week 10) questions (Anatomy, Immune System, Blood, Histology)

Lymphocytes

Effector cells of the immune system

B-cells

Lymphocytes that mature in the bone marrow and differentiate into antibody-producing cells

T-cells

Lymphocytes that mature in the thymus and express T-cell receptors (TCR)

Reticular cells

Supporting cells of the immune system that form the stroma

Lymph nodes (locations)

Encapsulated organs concentrated in cervical, axilla, groin, and mesenteries

Lymph node stromal cells

Reticular cells, dendritic cells, and macrophages in the lymph nodes

Follicular DC

Stromal cells in the lymph nodes that display antigen/antibody complexes for years

Thymic cell education

Process of T-cell differentiation and maturation in the thymus

CD2/CD7 T-cells

T-cells that migrate from bone marrow to thymus and express CD2 and CD7

Positive selection

Process in the thymus where double positive cells recognize self-antigens on MHC I and survive

Negative selection

Process in the thymus where double positive cells recognize self-antigens on MHC II and undergo cell death

Lymphocytes

Effector cells of the immune system.

Primary lymphoid organs

Bone marrow and thymus gland.

Secondary lymphoid organs

Diffuse lymphatic tissue, lymph nodes, spleen, adenoids, appendix, and tonsils.

Lymphatic system

The network of lymphatic vessels and organs involved in immune response.

Lymphocytes

B-cells, T-cells, and NK cells.

Supporting cells

Monocytes/Macrophages, dendritic cells, PMNs, and reticular cells.

Lymphocyte movement

Constant circulation of lymphocytes between blood, lymphatics, and surrounding tissue.

T-lymphocytes

Mature in the thymus, express TCR, CD2, CD3, CD5, and CD7, and differentiate into different subsets.

B-lymphocytes

Mature in bone marrow, differentiate into antibody-producing cells, and express BCR, MHC II, CD9, CD19, and CD20.

NK cells

Do not mature in the thymus, express CD16a, CD56, and CD94, and have similar functions to T-cytotoxic cells.

Lymphatic vessels

Vessels that collect lymph and transport it to lymph nodes and eventually back to the bloodstream.

Diffuse lymphatic tissue (MALT)

Lymphatic tissue located in the lamina propria, including lymphatic nodules.

Lymph nodes

Encapsulated lymphoid organs with cortex and medulla, involved in immune response and filtration.

Lymph node stromal cells

Reticular cells, dendritic cells, macrophages, and follicular dendritic cells present in the lymph nodes.

Thymus

Bi-lobed organ located in the superior mediastinum, involved in T-cell maturation and education.

Thymus cortex

Dense basophilic region packed with T-cells and epithelioreticular cells.

Thymus medulla

Region similar to the cortex but with larger T-cells and epithelioreticular cells.

T-cell differentiation/maturation

Process in the thymus where T-cells migrate, express specific markers, and undergo positive and negative selection.

Red pulp

Region of the spleen with splenic sinuses and splenic macrophages involved in the destruction of damaged RBCs and bacteria.

Splenic Circulation

The circulation of blood within the spleen, involving the splenic arterioles, periarteriolar lymphoid sheath (PALS), white pulp, red pulp, and trabecular arteries and veins.

White pulp

The region of the spleen composed of lymphoid tissue, including the periarteriolar lymphoid sheath (PALS) and germinal centers, where immune responses are initiated.

Lymphatic Nodules

Small clusters of lymphoid tissue found in various organs, such as the bronchus-associated lymphatic tissue (BALT), gut-associated lymphatic tissue (GALT), and mucosa-associated lymphatic tissue (MALT).

Lymph Nodes (distribution and visible structure)

Small, bean-shaped organs distributed throughout the body that filter lymph and generate immune responses to antigens.

Spleen

A large lymphoid organ located in the upper left abdomen, involved in immune surveillance, filtering blood, and generating immune responses to circulating antigens. It consists of red pulp and white pulp.

Diffuse lymphatic tissue

Lymphoid tissue scattered throughout various organs, such as the gastrointestinal tract, respiratory tract, and urinary tract, involved in immune surveillance and defense.

Periarteriolar lymphoid sheath (PALS)

The region of the white pulp in the spleen mainly composed of T cells.

Germinal centers

Areas within lymphoid tissue where B cells proliferate and differentiate into antibody-producing plasma cells.

Macrophages

Phagocytic cells involved in engulfing and destroying pathogens and cellular debris.

High endothelial venules (HEVs)

Specialized blood vessels found in lymphoid tissues that allow lymphocytes to enter from the bloodstream.

Reticular meshwork

A network of reticular fibers that provides structural support to lymphoid organs and facilitates the movement of immune cells.

Hassall's corpuscles

Concentrically arranged epithelial cells found in the medulla of the thymus, involved in the maturation of T lymphocytes.

Penicillar arteries

Small arteries in the spleen that deliver blood to the red pulp.

Trabecular arteries and veins

Blood vessels located in the trabeculae of the spleen, involved in the circulation of blood within the organ.

A cell expressing CD3. CD25, and FOX P3 is a what?

Regulatory T-Cell

Immune System

The collection of cells, tissues, and molecules that mediate resistance to infections and other foreign substances in the body.

Inflammation

A response to tissue damage, characterized by heat, pain, redness, swelling, and loss of function. It involves the release of inflammatory mediators and increased blood supply.

Phagocytosis

The process by which cells engulf and digest foreign particles or microorganisms.

Complement

A group of serum proteins that play a role in the immune response, including opsonization, lysis of bacteria and viruses, inflammation, and clearance of immune complexes.

Innate Immune Response

The non-specific, fast-acting response of the immune system that does not require prior exposure to a specific pathogen.

Adaptive Immune Response

The specific, slower response of the immune system that involves the recognition and targeting of specific pathogens.

First Line of Defense

The physical, chemical, and biological barriers that prevent the entry of pathogens into the body, such as the skin, mucous membranes, and normal flora.

Second Line of Defense

The inflammatory response and other non-specific mechanisms that are activated when pathogens breach the first line of defense.

Third Line of Defense

The adaptive immune response, which involves the activation of specific immune cells and the production of antibodies.

Pattern Recognition Receptors (PRR)

Receptors that recognize specific molecular patterns on pathogens, triggering an immune response.

TLRs (Toll-like Receptors)

A type of pattern recognition receptor that is located on the cell surface or in endosomes and recognizes specific pathogen-associated molecular patterns.

Opsonization

The process of coating pathogens with molecules (such as complement proteins) to enhance their recognition and phagocytosis by immune cells.

Lysis

The destruction of bacteria and enveloped viruses by the formation of membrane attack complexes (MAC) through the complement cascade.

Chemotaxis

The movement of immune cells towards a site of inflammation or infection, guided by chemical signals.

Antibody

A protein produced by B cells in response to a specific antigen, capable of binding to and neutralizing the antigen.

Memory

The ability of the adaptive immune system to "remember" previous encounters with specific pathogens, resulting in a faster and more effective response upon re-exposure.

Classical pathway

One of the three pathways of the complement system that is activated by antigen-antibody complexes.

Alternative pathway

One of the three pathways of the complement system that is activated by microbial surfaces.

C1qr2S2

A complex formed by the activation of C1q, C1r, and C1s in the classical pathway of the complement system.

C4 & C4

A component of the complement system that is involved in the activation of the classical pathway.

C3

A component of the complement system that is involved in the activation of all three pathways.

C3bB

A complex formed by the activation of C3b and factor B in the alternative pathway of the complement system.

C4a

A fragment generated during the activation of C4 in the classical pathway of the complement system.

C3a

A fragment generated during the activation of C3 in the complement system.

Proteases

Enzymes that cleave proteins.

MASP-2

Mannan-binding lectin-associated serine protease 2, an enzyme involved in the lectin pathway of the complement system.

C4b

A fragment generated during the activation of C4 in the complement system.

C3b

A fragment generated during the activation of C3 in the complement system.

Factor-B

A component of the complement system that is involved in the activation of the classical pathway.

MBL and ficolins

Pattern recognition molecules involved in the lectin pathway of the complement system.

C4b2

A complex formed by the activation of C4b and C2 in the classical pathway of the complement system.

Factor D

A component of the complement system that is involved in the activation of the alternative pathway.

C2b

A fragment generated during the activation of C2 in the classical pathway of the complement system.

C3 Ba

A fragment generated during the activation of C3 in the complement system.

C4b2a

A complex formed by the activation of C4b2 and C3bBb in the classical pathway of the complement system.

C3a

A fragment generated during the activation of C3 in the complement system.

C3b

A fragment generated during the activation of C3 in the complement system.

C5, C6, C7, C8, C9

Components of the complement system that is involved in the formation of the membrane attack complex.

C5b

A fragment generated during the activation of C5 in the complement system.

C5a

A fragment generated during the activation of C5 in the complement system.

C5b67

A complex formed by the activation of C5b and C6-C7 in the complement system.

C5b-9

A complex formed by the activation of C5b and the subsequent addition of C6-C9 in the complement system.

Surface site

The location on a cell or microorganism where complement proteins bind.

Phagocytosis

The process by which cells engulf and internalize particles or microorganisms.

Attachment (TLR/CR/Fc)

The initial binding of phagocytes to pathogens or particles through Toll-like receptors (TLRs), complement receptors (CRs), or Fc receptors (FcRs).

Recognition

The recognition of pathogens or particles by phagocytes through various receptors.

Engulfment (phagosome)

The internalization of pathogens or particles by phagocytes, forming a phagosome.

Fusion of phagosome with lysosome

The fusion of the phagosome with a lysosome, forming a phagolysosome.

Digestion

The degradation of pathogens or particles within the phagolysosome.

Expulsion/Ag presentation

The expulsion of undigested material from the phagocyte and the presentation of antigens to other immune cells.

Phagocytes (Types)

Different types of phagocytic cells, including neutrophils, monocytes, dendritic cells, and osteoclasts.

Antigen (Ag)

A molecule that can be recognized by the immune system and elicit an immune response.

Epitopes

Specific regions on an antigen that are recognized by antibodies or T cell receptors.

Antibody (Ab) or Immunoglobulin (Ig)

Proteins produced by B cells that can bind to specific antigens.

Immobilize

The ability of antibodies to prevent the movement or activity of antigens.