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Development of Orofacial Structures
Terms in this set (51)
early features of facial development
Early features of facial development can be seen by what week of embryonic age? What can be seen during this time?
3 ridges (U-shaped bars) of tissue are visable
The three ridges of tissue visible at the 3rd week of embryonic life is called what? How many of these arches eventually develop?
Pharyngeal (branchial) arches
6 total arches (first 3 are largest)
First arch is called what?
Second Arch is called what?
A relatively hollow tube running through the middle of the body cavity is divided into three parts. What are these parts? Starting at the top to the bottom?
Foregut, midgut, and hindgut
At 4.5 weeks of embryonic life, the foregut does what? By doing this, it forms what?
Foregut breaks down and connects with the stomodeum. Forms the oral cavity and oral pharynx.
At 6-7 weeks, the hindgut does what? Becomes what?
Breaks down and becomes the anal and urethral openings.
Stomodeum is a depression called what?
Primitive oral cavity
The mandibular arch (1st Arch) begins to show growth and divides into what?
Maxillary and Mandibular processes
Mandibular process forms what?
Maxillary process forms what?
Maxilae, the zygomatic bones of the cheek, and the palatine bones
Frontal process forms what?
Give rise to the upper part of the face, nasal septum, and the anterior portion of the hard palate.
The face and all parts of the oral and nasal cavities are formed from the first pharyngeal arch and the frontal process other than WHAT exception? This exception is formed from which of the arches?
The tongue is formed from pharyngeal arches II, III, and IV.
When do the nasal pits form? Describe the nasal pits and their location
At four weeks of embryonic life. Two small depressions formed low on the frontal process
The areas on either side of the nasal pits begin to form a ridge and it becomes what?
Medial and Lateral nasal processes.
At four weeks of embryonic life, the maxillary processes are beginning to do what?
Enlarge and seem to be growing toward the midline.
When the two medial nasal processes have fused together, what is formed? What week of embryonic life does this happen? What also helps form the upper lip? WHAT ELSE is formed from these same processes fusing together?
6th week. Forms upper lip.
Also right and left maxillary processes. Palate is also formed by these processes.
What is the cause of a cleft lip? When is it usually shown if at all?
Cleft palate usually develops around what week of embryonic life?
If the groove between the two processes does not fill with connective tissue, there is a separation known as a cleft lip.
7th to 11th week the cleft palate will show if evident.
What does the philtrum form from?
First signs of tooth development are seen at what week of embryonic life?
6th week. No visible ridge shown in oral cavity at this time.
Thickened oral epithelium is known as what? Where is the thickening first seen?
Anterior midline and slowly spreads posterior toward molar regions.
At what week in embryonic development will there be 20 thickened dental lamina? This marks what and will form what?
Future deciduous teeth
Will form enamel of future teeth
What are the two layers of epithelial cells in the embryo? What is between the two layers?
1. Outer ectoderm
2. Inner endoderm
Mesoderm is between the two layers.
The Outer Ectoderm and the Inner Indoderm forms what? Mesoderm forms what?
ectoderm and endoderm will form enamel.
Mesoderm will form dentin, pulp, cementum
Tooth bud is organized into what 3 organs?
Enamel organ, Dental papilla, and dental sac.
Enamel organ is part of what? Forms what?
Tooth bud. Forms enamel
Dental papilla is part of what? Forms what?
Tooth bud. Forms dentin and pulp
Dental sac is part of what? Forms what?
Tooth bud. Forms cementum, alveolar bone, and periodontal ligament.
Tooth development is divided into what four main stages?
Crown maturation stage
Describe the bud stage?
-budding from 10 thickened areas in dental arches.
-first stage in the development of the enamel organ.
-buds look like blobs of cells from invaginating dental lamina into connective tissue.
-Buds become slightly concave which transitions into Cap stage
Describe the cap stage?
-Enamel organ enlarges
What three components make up the cap stage?
outer enamel epithelium (OEE), inner enamel epithelium (IEE), and stellate reticulum.
What is the OEE?
Outer enamel epithelium.
Direct continuation of the basal layer of the oral epithelium
What is IEE?
Inner enamel epithelium.
The cells that outline the concavity in the deepest part of cap stage.
Continuation with the outer enamel epithelium cells and also come from the basal layer of the oral epithelium
What is the stellate reticulum?
Describe the bell stage. Contains what that the cap stage doesn't? Where is this located?
fourth layer of epithelium called the stratum intermedium appears in addition to the components of the cap stage.
Located between IEE and Stellate reticulum
What two processes occur with bell stage?
1. Outline of the crown is determined by the way in which the cell layers expand as the enamel organ grows.
2. Changes in various cells especially IEE that lead to production of enamel.
protective layer for entire enamel organ. Later will play role in attaching gingiva to tooth
elongate and change internally to become ameloblasts (form enamel)
Stellate reticulum function?
Cushioned protection for IEE cells. Nourishment of stratum intermedium by allowing vascular fluids to move between
Statum intermedium function?
Help provide nourishment for IEE cells. Also make proteins and may receive products from and provide products for ameloblasts.
What is successional lamina?
Lingual extension of the dental lamina of developing primary teeth.
Forms permanent anterior teeth and premolars.
Dental papilla? Arises from? located close to? Forms what?
Small area of condensed cells arising from mesoderm and located close to the IEE. forms dentin and pulp.
Comprises several rows of flattened cells around dental papilla.
Enamel develops from the enamel organ which is derived from ectoderm whereas the dentin and pulp develops from the what which is derived from what?
dental papilla and derives from mesoderm
First mineralized tissue to appear in any developing tooth?
Where do odontoblasts come from? they form what at the what? They begin moving INWARD towards to center of the pulp.
Mesenchyman cells of the dental papilla.
Form a single layer of columnar cells at the dentinoenamel junction
Forms during dentinogenesis and is the remaining portion of the odontoblast that did not move toward the pulp.
Long tube running from the DEJ or DCJ to the pulp. Each tubule contains an ondontoblastic process
Newest, nonmineralized layer of the dentin
Sets with similar terms
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