COT Quiz 2 - BU MAMS

Mesoderm Layer

Layer that connective tissue originates from

Mesenchyme

Embryonic or fetal CT that has high cellularity (progenitors), fewer fibers, and lots of ground substance

Mesenchymal Stem Cells (MSC)

Fibroblasts, osteoblasts, chondroblasts, myoblasts, and adipocytes are derived from this type of stem cell

Muscle, Adipocyte, Fibroblast

Three types of non-motile cells that are derived from MSCs

Embryonic and Fetal Development

When are muscle progenitors formed?

Transdifferentiation

Biological process where one mature cell type transforms directly into another mature cell type

Dedifferentiation

Biological process where specialized, mature cells revert to a simpler, less specialized, and often proliferative state

Unilocular Adipocytes (White Fat Cells)

These cells are responsible for energy storage and are called upon first as a source of energy during starvation

Multilocular Adipocytes (Brown Fat Cells)

These cells store lipid and are specialized for heat production; they are rich in mitochondria and strongly eosinophilic

Beige Fat Cells

Converted white fat cells that adopt the heat-generating properties of multilocular cells

Cells, Fiber, Ground Substance

Three basic components of connective tissue

Fibroblast

Cells that are chiefly responsible for the production, remodeling, and degradation of the extracellular matrix fibers and ground substance

Myofibroblast

Myosin-producing subtype of fibroblasts specialized to generate force

Elastin (Core), Fibrillin (Microfibrils)

Two types of proteins that compose elastic fibers

Verhoeff’s Stain

What type of stain is used to visualize the elastin fibers of a tissue?

Type I Collagen

Dominant large fiber of connective tissue, playing structural and space-filling roles

Type III Collagen (Reticular Fibers)

Dominant small fiber of connective tissue, and the dominant fiber in mesenchyme; provides support in regions that are predominately cellular

Type IV, Type VII

Types of collagen that are found within the external and basement membranes

Lamina Lucida, Lamina Densa, Lamina Reticularis

Layers of external membrane

Lamina Densa

Layer of external membrane that is made of type IV collagen

Lamina Reticularis

Layer of external membrane that is made of type VII collagen

Proteoglycans

Major component of ground substance

Hyaluronic Acid

What serves as the “backbone molecule” in proteoglycans?

Glycosaminoglycans (GAGs)

Molecules that attach to proteins (part of proteoglycans) and are polar, binding large numbers of surrounding water molecules through Van der Waals forces

Elevated Type III

What type of collagen predominates in scars?

Cyst

Immune system response that “walls off” a certain area by depositing a thick sheet of fibrous CT

Freeze Fracture EM

Electron microscopy technique where a rapidly frozen section is then cracked; separation leads to E-face (extracellular) and P-face (protoplasmic, intracellular)

Inflammation, Innate Immunity, Adaptive Immunity

The order in which HSC-derived cells respond

Mast Cell, Eosinophil, (Basophil)

HSC-derived cells that are used for the inflammatory response

Macrophage, Neutrophil

HSC-derived cells that are used for innate immunity

Lymphocyte, Plasma Cell

HSC-derived cells that are used for adaptive immunity

Cytokines

Molecules that communicate in a paracrine manner with other cells

Diapedesis

Process by which leukocytes leave the circulation and enter the connective tissue

Paracellular Diapedesis

Form of diapedesis in which the migratory cell moves through the transiently broken junctional complex between two epithelial cells

Transcellular Diapedesis

Form of diapedesis in which the migratory cell pierces the endothelial cell body (most common in bone marrow)

Selectins, ICAMs

Molecules that mediate leukocyte diapedesis

Macrophages, Neutrophils, Lymphocytes

In acute inflammation, what cell types produce cytokines?

Stromal Cells (e.g. fibroblasts)

In chronic inflammation, what cell types produce cytokines?

Histamine, Heparin

Two types of granules that are found in mast cells

Metachromatic Granules (in Mast Cells)

Intracellular storage structures found in certain microorganisms that stain a different color than the dye applied to them

Compound Exocytosis (in Mast Cells)

Mechanism for quick degranulation that is primarily activated through binding with surface IgE antibodies

Eosinophil

Type of leukocyte that is uniquely anthelmintic; they also have functions that include mediating allergic responses

Major Basic Proteins

Example of eosinophil-specific granules that are distinctive in EM images

Charcot-Leyden Crystal

Product of eosinophil degranulation that has a characteristic pathological appearance

Primary (Azurophilic), Secondary (Specific), Tertiary (Gelatinase)

What are the three types of granules in neutrophils?

Tertiary Granules

Granules that facilitate migration to the target

Specific (Secondary) Granules

Granules that kill bacteria with enzymes and reactive oxygen compounds

Azurophilic (Primary) Granules

Lysosomal enzymes (granules) that digest bacteria

Spleen

Where is the “reserve pool” of macrophages stored?

Systemic Macrophages

Macrophages that are derived from circulating monocytes, which are born in the bone marrow, leave the circulation through diapedesis, and enter various connective tissue compartments

Resident Macrophages

Macrophages that are seeded from monocytes during embryonic or fetal development, and subsequently repopulate themselves as needed

Langhans Cell, Foreign Body Giant (FBG) Cell

Types of macrophage syncytia

Cytotoxic, Helper

Two major classes of T-cells

Hematopoietic Tissue

Where do B-cells undergo the process of attaining immunocompetence?

Thymus

Where do T-cells undergo the process of attaining immunocompetence?

Plasma Cell

Term for “activated” B-cells that represent the only stage of any of the lymphocytes that possess a unique morphology

MALT (Mucosa-Associated Lymphoid Tissue)

Aggregations of lymphocytes that are often found together in large congregations in the CT underlying mucosal surfaces

B-Lymphocyte

Lymphocytes that work via antigen-antibody recognition and undergo activation / clonal expansion when an antigen is recognized

T-Lymphocyte

Lymphocytes that recognize self from non-self cells through MHC-molecule recognition via the T-cell receptor

innate Lymphocyte Cells

A diverse group of lymphocytes that are NOT reliant on antibodies nor MHC-molecule recognition

Stem, Progenitor, Precursor, Mature

Cells that represent patterns of cellular development (in order)

Stem, Progenitor

Two types of cells that can self-renew (and also differentiate/die)

Embryonic Stem Cell

True human stem cells that are prevalent in the blastocyst phase of development, after which they quickly become differentiated

Erythrocytes, Macrophages, Granulocytes, Mast Cells

Types of myeloid cells (originating from HSCs)

B-Cells, T-Cells, NK

Types of lymphoid cells (originating from HSCs)

G0 Phase

What phase are cells that have left the cell cycle and are termed quiescent in?

G1, S (Duplication of Chromosomal Material), G2, Mitosis

Stages of the cell cycle

p53 Protein

G1S checkpoint protein that is most commonly associated with cancer-causing genetic abnormalities

Sweat Gland Ducts

Typical location(s) for stratified cuboidal epithelia

Inner Eyelid, Large Ducts

Typical location(s) for stratified columnar epithelia

Respiratory System

Typical location(s) for pseudostratified epithelia

Urinary System

Typical location(s) for transitional epithelia

Spermatogonia, Oogonia

What are the M/F gametes called when they are progenitor cells?

Primary Spermatocytes, Primary Oocytes

What are the M/F gametes called before meiosis I?

Secondary Spermatocytes, Secondary Oocytes

What are the M/F gametes called before meiosis II?

Spermatids (in male)

What are the M/F gametes called when they are precursor cells?

Spermatozoa, Ova

What are the M/F gametes called when they are adult cells?

Apoptosis

Caspase-dependent pathway for cell death; present in normal development and does not have an immune response; leads to pyknotic nucleus and cytoplasmic blebbing

Necrosis

Caspase-independent pathway for cell death; almost always pathological and has an immune response; leads to nuclear fragmentation and hypereosinophilia

PAMP (Pathogen-Associated Molecular Pattern)

Elicits an immune response to clear a foreign invader

DAMP (Damage-Associated Molecular Pattern)

Elicits an immune response to clear necrotic tissue (from extracellularization of DNA/RNA)

PRR (Pattern Recognition Receptors)

PAMPs and DAMPs activate an innate/adaptive immune response by binding to these receptors

NETosis (Neutrophil Extracellular Trap)

Type of cell death where chromatin is expelled upon the death of a neutrophil that ensnares extracellular bacteria and fungi

Autophagy

Process that may either rescue a stressed cell (by “eating” its own organelles) if the stress is removed) or induce apoptosis/necrosis

Coagulative, Caseous Liquefactive

Types of chemical dissolution tissue necrosis

Fat (Adipose Tissue), Blood Vessel Wall (Fibrinoid Necrosis)

Types of special tissue necrosis

Cyst/Abscess, Gangrenous

Types of scarring (CT wall) tissue necrosis

Pus

Colloquial term for whitish fluid consisting mainly of dying immune cells (e.g., neutrophils)

Coagulative Necrosis

Firm dying tissue, indicating an acute loss of blood to the region; the organ’s structure typically is either retained/preserved through fibrous deposition

Liquefactive Necrosis

Fluid dying tissue, produced when the dominant response is of neutrophils (granules act to dissolve/liquify tissue); neural tissue shows a preference for this type of necrosis

Caseous Necrosis (Cheese-Like)

Dying tissue that is a balanced response of macrophages, neutrophils, and lymphocytes, specific to diseases such as tuberculosis

Proteoglycans

Ground substance of cartilage

Hydroxyapatite (Calcium Phosphate Crystals)

Ground substance of bone, also making up the inorganic component of the bone matrix

Hyaline, Elastic, Fibrocartilage

What are the three main types of cartilage?

Perichondrium

Vascular layer of dense sheet-like connective tissue that surrounds most types of cartilage in the body; it has an outer fibrous portion and an inner chondrogenic portion

Chondroblasts

Cells responsible for making cartilage matrix

Chondrocytes

Mature chondroblasts that get trapped in their own matrix and can produce/maintain matrix; usually in isogenous groups

Properties include:

• Abundant RER and stain basophilic

• Large Golgi complex that shows as cleared area of cytoplasm

Capsular (Type VI), Territorial (Ground Substance), Interterritorial (Type II)

Three types of matrix in ECM of cartilage

Hyaline Cartilage

Type of cartilage that is found in the nose, respiratory system, and fetal skeleton

Properties:

• Type II collagen fibers

• Has a perichondrium

• Can calcify with age

Elastic Cartilage

Type of cartilage that is found in the epiglottis and most of the external ear

Properties:

• Hyaline cartilage + elastic fibers

• Chondrocytes more likely to be in singlets

• Has a perichondrium

• Does NOT calcify with age