Ch.18 Development Of Orofacial Complex Flashcards
What are the 3 Embryologic Stages?
- Period of the Ovum-Fertilization through 2 weeks
- Period of the Embryo(embryologic)- Weeks 3-8
- Period of the Fetus- Weeks 9-36
At what stage do the early features of the face begin to develop?
The Embryonic Stage (3 Weeks)
What is the tube called that is closed on upper and lower ends and runs through the middle of the body?
The developing digestive tract
How many parts is the Developing Digestive Tract divided into?
3
What are the 3 parts of the Developing Digestive Tract?
- Foregut(upper part)- forms Digestive tube from throat region to the duodenum.
- Midgut(Middle Portion)-Forms the rest of the small intestine, cecum, ascending colon, and most of the transverse colon.
- Hindgut(lower)-Forms descending colon, sigmoid colon, and rectum of large intestine.
At what age does an embryos length measure approximately 3-4 mm from the top of the head to the tail area?
3 weeks old
The primitive oral depression is known as what?
Stomodeum
What arches are identified as Roman numerals l and ll?
The upper two pharyngeal arches
What are the upper two pharyngeal arches?
l. Mandibular Arch
ll. Hyoid Arch
Which of the pharyngeal arches begin to show growth which will be the maxillary process?
The Mandibular Arch
The mandibular Arch can be subdivided into 2 different processes being?
Mandibular Process and Maxillary Process
What will the mandibular process form?
The Mandible
What will the Maxillary Process form?
- The Maxillae
- The zygomatic Bones of the cheeck
- The Palatine bones
What do the palatine bones form?
The hard palate in the food of the mouth
Nasal Pits
Small depressions that form low on the frontal prominence during the 4th embryonic week
What do the 2 medical nasal processes do by the 6th week?
They fuse together and, along with the two Maxillary Processes, form the upper lip
What fills in the groove that lies between the two nasal processes?
The medial nasal and the Maxillary processes
Migration
When there is an increase in the connective tissue of the upper lip area of the groove and the groove fills in and slowly disappears
Cleft lip
When a migration fails and separation occurs between the medial nasal Process and Maxillary Process
When does cleft lip form?
Around the 6th embryonic week
Hare Lip
When the two medial nasal processes do not fuse together (midline cleft of the upper lip)
How did hare lip get it’s name?
It resembles the cleft in the upper lip of a rabbit
What Forms the hard palate?
The right and left Maxillary processes and the medial nasal processes
What happens during the 11th week of development with the 2 Maxillary Processes?
After fusing with the primary palate they then fuse with one another.
-This happens 1st in the anterior region then moves backwards like a zipper being zipped from front to back.
What happens during the 7th-8th week of development with the 2 Maxillary Processes?
Fuses with the primary palate
Around how many weeks of development does the cleft palate usually develop?
Between the 7th and the 11th week
A combined cleft lip and palate occurs in about how many births for whites?
1:700
What race is cleft lip more common in?
Asians
Ratio- 1:350
Cleft lip is less common in what race?
Blacks
Ratio- 1:1400
What is the ratio for cleft lip that involves only the palate and not the lip?
1:2500
What are the two most common types of cleft lip?
Unilateral and bilateral clefts
What can be treated surgically with good results?
Cleft Lip
When does cleft lip develop?
3-6 weeks after fertilization
What kind of factors are involved in the development of clefts?
Hereditary
Environmental Factors (People that have a greater risk of suffering from birth defects such as cleft lips) :
Pregnant woman abuses various kinds of drugs(legal/illegal), smokes/drinks heavily, or is in an environment that may have potentially damaging pollutants
Pharyngeal grooves (clefts)
The depressions on the neck surface
Pharyngeal pouches
The depressions on the inside of the neck
What does each arch consist of?
- Bar of cartilage
- An artery
- A cranial nerve
- A mesodermal tissue
What are the 3 cranial nerves and their arches?
1. Trigeminal (Arch l) 2. Vll (Facial) (Arch ll) 3. lX Glossopharyngeal (Arch lll) 4. X (Xl) Vagus (Accesory) (Arch lV and Vl)
Muscle(s) of the trigeminal cranial nerve:
- Muscles of Mastication
- Mylohoid
- Anterior digastric
- Tensor tympani (in ear)
- Tensor veli palatine
Muscle(s) of the facial (Vll) cranial nerve:
- muscles of Facial Expression
- Posterior digastric
- Stylohyoid
- Stapedius (in ear)
Muscle(s) of the glossopharyngeal (lX) cranial nerve:
Stylopharyngeus
Muscle(s) of the Vagus (X or Xl) cranial nerves:
- Muscle of larynx
- Muscle of pharynx
- Most muscles of soft palate
Cartilage/Bone in trigeminal cranial nerve:
Malleus and incus bones
Cartilage/Bone in Facial cranial nerve:
- Stapes
- Styloid Process
- Lesser corny of hyoid
- Upper body of hyoid
Cartilage/Bone of the glossopharyngeal cranial nerve:
- Greater cornu if hyoid
- Lower body of hyoid
Cartilage/Bone of the Vagus cranial nerve:
Cartilages of larynx
A small depression in the middle of the tongue is know as what?
Foramen Cecum
The point where the thyroid gland begins to develop and then migrate downward, eventually lying in the lower front neck region is called what?
Foramen Cecum
What is it called when the patients tube doesn’t grow downward but instead forms into a big red lump at the back of the tongue?
Lingual Thyroid Nodule