aknight1302's version from 2015-11-17 16:36


Return to Microanatomy Test 4 TOC


Question Answer
Stomatodeumcavity between Frontal Prominence and Cardiac Bulge (embryo development of mouth) 25th day
First Pharyngeal Arch differentiates intomaxillary and mandibular processes (embryo development of mouth)
Epithelium derived component of toothEnamel
Neural Crest, origin of all tooth structures EXCEPT ____?enamel
Enfolding from epithelium into ectomesenchyme that will develop into tooth budsDental Laminae (max and man)
What is between the ectomesenchyme and epithelium of the Dental Lamina?Basement Membrane
What starts developing first? enamel or dentinDentin starts first, (though the pre-odontoblasts are stimulated to differentiate and then build dentin by the pre-ameloblasts... pre-ameloblasts don't start creating enamel layer until there is dentin to build it against)... basement membrane is still present initially
Layers of the Enamel OrganInternal Enamel Epithelium (IEE), External Enamel Epithelium (EEE), Stellate Reticulum, stratum intermedum
What LAYER of the ENAMEL ORGAN adjoins the DENTAL PAPILLA?Internal Enamel Epithelium (enamel genesis from this layer)
What LAYER of the ENAMEL ORGAN adjoins the DENTAL FOLLICLE?External Enamel Epithelium (EEE)
What LAYERS surround the STELLATE RETICULUM?IEE and EEE (Stellate Reticulum is middle layer of the ENAMEL ORGAN, which is of epithelial origin)
What ectomesenchymal structure surrounds and encapsulates the enamel organ?Dental Follicle
What ectomesenchymal structure invaginates the enamel organ?Dental Papilla
During what stage is the ENAMEL KNOT visible? and where?cap stage, disappears by bell stage... found in the stellate reticulum adjoining the center of the IEE
Ectomesenchymal tissue has its origins in the ____ ____Neural Crest
What tooth structure(s) is/are derived from the ENAMEL ORGANenamel
What tooth structure(s) is/are derived from the DENTAL PAPILLAdentin and pulp
What tooth structure(s) is/are derived from the DENTAL FOLLICLE (SAC)Cementum, Periodontal Ligament, Alveolar Bone
Cervical Looparea where IEE and EEE meet, BECOMES CEJ and is boundary of crown formation, appear in the bell stage
What is the cell type of Preameloblasts?"low" columnar, w/ central nuclei
What induces the differentiation of Preameloblasts into Secretory Ameloblasts?presence of Mineralized Dentin across basement membrane (specifically, Mantle Dentin is the Dentin that is deposited against the basement membrane... triggering the differentiation of PreAmeloblasts into Secretory Ameloblasts)
Where are HYAP crystals formed in enamel formation? (structure, cell, tissue layer)in the Tomes' Processes of Secretory Ameloblasts in the Internal Enamel Epithelium
What is orientation of Distal Tomes' Process product to the cell producing it?parallel (or an extension of the same line), this forms Rod Enamel and fills the pits made by walls of Inter-rod Enamel
What is orientation of Proximal Tomes' Process product to the cell producing it?perpendicular, this forms Inter-Rod Enamel and creates walls for formation of Rod Enamel
What IS the product of Secretory Ameloblasts?ENAMEL, (specifically Needle-like HYAP crystals sheathed in enamel proteins) (proteins digested and crystals grown to become Enamel as we know it)
How many Ameloblasts make the transition from SECRETORY to MATURATIVE?about 50% undergo APOPTOSIS, others become Maturative
What is the function of Maturative Ameloblasts?Enamel Hardening
What are the 2 types of Maturative Ameloblasts?Ruffle-bordered and Smooth-bordered
What do Ruffle-bordered Ameloblasts do?secrete calcium ions for crystal growth, (enamel hardening), Ruffle-bordered are Maturative Ameloblasts
What do Smooth-bordered Ameloblasts do?uptake digested polypeptides (cleared enamel matrix/crystal sheaths... make room for crystal growth), Smooth Bordered are Maturative Ameloblasts
What does the Enamel Organ become after Enamel formation is complete?Reduced Enamel Epithelium
What is the difference between Pre-Dentin and Dentin?Pre-Dentin is newer (just formed) and UNMINERALIZED, Dentin is MINERALIZED and used to be pre-dentin
Fusion of IEE and EEE happens where, when and forms what?happens at cervical loop, coinciding with tooth eruption, forms HERTWIG's EPITHELIAL ROOTH SHEATH
lifecycle of Hertwig's Epithelial Root Sheath1. at tooth eruption FORM, comprised of IEE and EEE 2. communicate with Odontoblasts to differentiate into RADICULAR odontoblasts (form root dentin, NOT crown dentin) 3. Break Down (Herwtig's Root sheath has done its job and now recedes) (goodbye Hertwig)
function of Hertwig's Epithelial Root Sheathcause differentiation of pre-odontoblasts --> radicular odontoblasts (end crown formation, start root formation)
What induces the differentiation of Cementoblasts?the breakdown of Hertwig's Root Sheath and presence of Radicular Dentin
What factors influence Crown Pattern Differentiation?Homeobox Genes (intial signal ... which to secrete... by ENAMEL KNOT in early cap stage, signals to dental papilla... which controls tooth differentiation)
Which mineralized tissue in the tooth has the greatest hardness?enamel (this is because of its rigid and highly inorganic composition HYAP)(it is also more brittle, or and has less tensile strength)
Which mineralized tissue in the crown of the tooth has the greatest tensile strength (acts as a shock absorber)?Dentin (because it's greater protein makeup relative to enamel, it has greater tensile strength and is less brittle.)
Morphodifferentiation, (bell stage)Crown of tooth determines its final shape (MORPHODIFFERENTIATION of the tooth)
Histodifferentiation, (bell stage)differentiation to Ameloblasts and Odontoblasts (IEE and Dental Papilla respectively)
At what stage does the Dental Lamina "disappear"?Bell stage
mnemonic for distal vs. proximal tomes process and their products?DRIP. Distal-Rod Interrod-Proximal (dpTP, ppTP)
What cells are found in a single layer lining the pulp cavity?odontoblasts