Exam 1 Histology Flashcards
The primitive streak forms in the embryonic disc during prenatal development, causing:
a. initiation of palatal development.
b. bilateral symmetry.
c. fusion of the mandibular processes.
d. disintegration of the oropharyngeal membrane.
b. bilateral symmetry.
* During the beginning of the third week of prenatal development within the embryonic period, the primitive streak forms within the bilaminar disc. The primitive streak causes the disc to have bilateral symmetry,*
* with a right half and left half.*
What is cleavage and when does it occur?
Cleavage – the process during prenatal development when mitosis converts a zygote to a blastocyst
After fertilization, the zygote then undergoes mitosis, or individual cell division, that splits it into more and more cells due to cleavage. After initial cleavage, the solid ball of cells becomes a morula. Because of the ongoing process of mitosis and secretion of fluid by the cells within the morula, the zygote now becomes a blastocyst (or blastula). The rest of the first week is characterized by further mitotic cleavage, in which the blastocyst splits into smaller and more numerous cells as it undergoes successive cell division by mitosis.
When does the maxillary and nasal processes form?
4th week
The migratory cells located in the middle between the epiblast and hypoblast layers become mesoderm, an embryonic connective tissue, as well as embryonic ______.
endoderm
Neuroectoderm
specialized group of cells that differentiates from ectoderm. Gives rise to the respiratory epithelium and cells of glands
The neural crest cells migrate from the crests of the neural folds and then join the _______ to form mesenchyme.
mesoderm
By the end of the ______ week, the mesoderm additionally differentiates and begins to divide on each side of the tube into 38 paired cuboidal segments of mesoderm, forming the _____.
third; somites
Hypoblast
inferior layer from the bilaminar embryonic disc composed of small cuboidal cells.
After a morula cleaves through additional mitotic divisions it is now called a __________
blastocyst
How many processes are included in facial development?
Facial development depends on the five major facial processes that form during the fourth week and surround the primitive mouth of the embryo:
1. frontonasal process.
2/3. mandibular process (paired)
4/5. maxillary process (paired)
- The line of demarcation between the attached gingiva and the alveolar mucosa is the:
a. mucogingival junction.
b. interdental gingiva.
c. mucobuccal fold.
d. marginal gingiva.
a.mucogingival junction.
Junctional epithelium
the epithelial attachment provides a seal at the base of the sulcus
non keratinized separates the periodontal ligament from the oral environment
- The development of the neck parallels the development of the face over time, beginning during the fourth week of prenatal development within the embryonic period and completed during the _____ period.
a. preimplantation
b. embryonic
c. fetal
d. both the embryonic and fetal
c.fetal
______ is the superior layer of the bilaminar embryonic disc
Epiblast
Where do the neural crest cells migrate from?
These cells migrate from the crests of the neural folds and then join the mesoderm to form mesenchyme.
The line of demarcation between the firmer and pinker attached gingiva and the movable and redder alveolar mucosa is the scallopp-shaped ________
Mucogingival junction
There are 4 muscles of mastication:
- Masseter
- Temporalis
- Medial pterygoid
- Lateral pterygoid
All attach to the mandible and are innervated by V3
Form in the tenth week of development
First arches (mandibular arches)
Which of the following muscles is involved in the lateral deviation of the mandible?
a. masseter muscle
b. medial pterygoid muscle
c. lateral pterygoid muscle
d. temporalis muscle
e. digastric muscle
c. lateral pterygoid muscle
What are the 3 stages of pregnancy?
Preimplantation period – first week (zygote, blastocyst)
Embryonic period – weeks 2-8 (disc, embryo, folded embryo)
Fetal period – months 3-9 (embryo, fetus)
- In which week of prenatal development does facial development begin in the embryo?
a. Second
b. Fourth
c. Fifth
d. Eighth
b.Fourth
The ______ of the hyoid arches helps form the muscles of facial expression, the middle ear muscles, and a suprahyoid muscle.
mesoderm
in week 3 (embryonic period), the Neural Crest Cells develop into what?
- ) components of nervous system pigment cells, connective tissue proper, cartilage, bone, certain dental tissue
- ) Histologic Features- Varies
- ) Origin- Migrating neuroectoderm
- What does the maxillary process form from during the fourth week of prenatal development?
a. Lateral nasal processes
b. Mandibular arch
c. Intermaxillary segment
d. Medial nasal processes
b.Mandibular arch
What exact cells or structures develop from neuroectoderm and migrate from the neural folds to then join mesoderm to form mesenchyme during the third week of prenatal development?
a. Somites
b. Neural crest cells
c. Mesoderm
d. Yolk sac
b.Neural crest cells
- In which of the following do the final stages of meiosis occur during prenatal development?
a. Placenta
b. Ovum
c. Sperm
d. Yolk sac
b.Ovum
Which specific muscle can become clinically enlarged in patients who habitually clench or grind (with bruxism) their teeth and in those who constantly chew gum?
a. Masseter muscle
b. Lateral pterygoid muscle
c. Medial pterygoid muscle
d. Temporalis muscle
a. Masseter muscle
Gingival margin
.
the edge of the gingiva nearest to the incised surface of the tooth
By the end of the _____ week of the preimplantation period, the blastocyst stops traveling and undergoes ______ and thus becomes embedded in the prepared endometrium, the innermost lining of the uterus on its back wall.
first; implantation
Which local anesthetic block anesthetizes the largest intraoral area?
A. Buccal block
B. Inferior alveolar block
C. Mental block
D. Incisive block
B. Inferior alveolar block
- Implantation of the zygote may also occur outside the uterus during prenatal development with a(n):
a. infection with rubella.
b. infection with syphilis.
c. ectopic pregnancy.
d. case of ectodermal dysplasia.
c.ectopic pregnancy.
_____ is the process of joining embryonic tissue of two separate surfaces, elimination of a furrow between two adjacent swellings, or development disturbances in which adjacent tooth germs unite to form large tooth
Fusion
Mesoderm
embryonic layer located between ectoderm and endoderm. Gives rise to CT such as skin dermis, cartilage, bone, blood, muscle, and associated other tissue
_____ is the embryonic layer located between ectoderm and endoderm.
Mesoderm
- Which of the following are considered cervical muscles?
a. Masseter and medial pterygoid muscles
b. Medial and lateral pterygoid muscles
c. Sternocleidomastoid and trapezius muscles
d. Buccinator and epicranial muscles
c.Sternocleidomastoid and trapezius muscles
Bilateral symmetry
Bilateral symmetry is when each half of an embryo mirrors the other half.
The ______ _____ provides anesthesia for the mandibular anteriors and premolars but only for the associated facial periodontium, and it can be used bilaterally without complications.
mental block
- On what structure do BOTH heads of the masseter muscle originate?
a. Zygomatic process of the maxilla
b. Coronoid process
c. Zygomatic process of the frontal bone
d. Zygomatic arch
d.Zygomatic arch
- When does the blastocyte stop traveling and undergo implantation during prenatal development?
a. First week
b. Second week
c. Third week
d. Fourth week
a.First week
- By the end of the first week of prenatal development, the blastula stops traveling and undergoes:
a. implantation.
b. migration.
c. disintegration.
d. amniocentesis.
a.implantation.
Lateral pterygoid
The superior head originates from the greater wing of the sphenoid. The inferior head originates from the lateral pterygoid plate of the sphenoid. The two heads converge into a tendon, which attaches to the neck of the mandible.
short thick almost conical muscle of mastication superior to the medial pterygoid. Two separate heads (superior an inferior). They are separated anteriorly by a slight interval but fuse together posteriorly.
The entire muscle lies within the infratemporal fossa deep to the temporalis muscle.
The only muscle of mastication that ASSISTS in depressing the mandible, lowering the lower jaw! Depression of the mandible occurs during the opening of the jaws. Protrusion also occurs when the jaws are opened
The muscle is innervated by the lateral pterygoid nerve, a branch of the mandibular nerve (V3)
Pterygomandibular space is formed by the lateral pterygoid muscle (roof), medial pterygoid muscle (medial wall), and the mandibular ramus (lateral wall). It is the injection site for the inferior alveolar block.
Which of the following is the BEST term used for the embryonic layer located between the ectoderm and the endoderm?
a. Mesenchyme
b. Ectomesenchyme
c. Mesoderm
d. Mesiodens
c. Mesoderm
After folding of the disc, the _____ lies inside the _____, with mesoderm filling in the areas between these two layers. This movement of the embryonic cell layers forms one long, hollow tube lined by endoderm from the cephalic end to the caudal end of the embryo
endoderm; ectoderm
Embryonic layers (germ layers)
increased number of embryonic cells within the blastocyst.
_____ is a layer in trilaminar embryonic disc derived from epiblast layer and lining stomodeum
Ectoderm
- The folding of the embryo during prenatal development causes _____ to be on the _____.
a. endoderm; inside of the embryo
b. ectoderm; inside of endoderm
c. endoderm; outside of the mesoderm
d. mesoderm; outside of the ectoderm
a.endoderm; inside of the embryo
What does the mandibular arch form from?
The fusion of the two mandibular processes
Gingival sulcus
The crevice between the free gingiva and the tooth.
- A type of cleft lip can result during prenatal development from the lack of fusion between _____ processes.
a. mandibular and maxillary
b. medial nasal and maxillary
c. lateral nasal and medial nasal
d. two lateral nasal
e. lateral nasal and maxillary
b.medial nasal and maxillary
How does cleft lip form?
Failure of fusion of the maxillary process
with the medial nasal process
The maxillary first molar is usually NOT a landmark for any maxillary nerve anesthesia, but the ______ _____ _____ is a landmark for the administration of the posterior superior alveolar nerve block.
maxillary second molar
Alveolar mucosa
The thin, moveable, loosely attached tissue covering the alveolar bone.
non keratinized
in week 3 (embryonic period), the trilaminar embryonic disc develops two ends called?
- ) Cephalic end (Head end)
- ) Caudal end (Tail end)
- The neural crest cells migrate from which embryonic structures during prenatal development?
a. Stomodeum
b. First branchial arch
c. Neural folds
d. Frontonasal process
c.Neural folds
After a zygote cleaves through mitosis it is now called a ________
morula
- The developmental disturbance of cleft lip is more commonly found:
a. in males.
b. bilaterally.
c. on the right side.
d. on the lower lip.
a.in males.
_______ means that each half of embryo mirrors the other half
Bilateral symmetry
At the cephalic end, the oropharyngeal membrane forms, which consists of only ______ externally and endoderm internally, without any intermediate mesoderm.
ectoderm
- On which of the following orofacial tissue is the linea alba located?
a. Attached gingiva
b. Marginal gingiva
c. Labial mucosa
d. Buccal mucosa
d.Buccal mucosa
Medial pterygoid
Rectangular form has 2 heads due to differing depth (deep and superficial, smaller head).
The superficial head originates from the maxillary tuberosity and the pyramidal process of palatine bone. The deep head originates from the lateral pterygoid plate of the sphenoid bone. Both parts attach to the ramus of the mandible, near the angle of mandible.
DEEPEST MUSCLE OF MASTICATION
Elevates the mandible during the closing of the jaws
Innervated by V3
What’s the diff b/w meiosis and mitosis
Meiosis – The process of reproductive cell production that ensures the correct number of chromosomes; meiosis that takes place during fertilization.
Mitosis – cell division that occurs in phases and results in two daughter cells; Mitosis is a process that takes place during tissue growth or regeneration
- Which of the following tissues listed will develop from the ectoderm layer of the embryo during prenatal development?
a. Epidermis
b. Liver
c. Muscle
d. Dermis
a.Epidermis
Masseter
Most superficial and strongest. Thick flat rectangular muscle on each side of the face, anterior to the parotid gland.
2 heads (superficial and deep)
Origin- Both heads originate from the zygomatic arch. Superficial =angle of the mandible. Deep = ramus
When the patient clenches their teeth is when the elevation of the mandible is taking place (closing of the jaws)
Innervated by the Masseteric nerve (V3)