DEH 103: Histology & Embryology
Chapters 3 & 4: Development of the Oral Facial Region & Development of the Face and Palate
Chapters 3 & 4: Development of the Oral Facial Region & Development of the Face and Palate
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Cartes-fiches
Malformations of embryos can be due to?
- Genetic factors (chromosomes)
- Environmental agents
- Factors
Environmental agents and factors can include?
- Infections
- Drugs
- Radiation
FRI: all considered teratogens
True/False:
All three layers of the embryonic disc form the face?
True
The oral cavity develops from?
Stomodeum
The oropharyngeal membrane gives rise to the?
Oral cavity
This initially appears as a shallow depression in the embryonic surface ectoderm at the cephalic end (head) before the 4th week prenantal.
Stomodeum
What are the 2 placodes of the facial area on a embryo?
- Lens
- Nasal
- Give rise to the eyes and ears
The first 2 arches are known as and develop into?
- 1st mandibular arch
- 2nd hyoid arch
- Develop greatest extent
What cartilage composes each arch?
- Meckel's cartilage
- Superior hyoid
- Interior hyoid
- Laryngeal
This refers to fill formation in the neck, so since humans do not have gills, they are often called ____ arches.
- Branchial
- Pharyngeal
The foregut gives rise to the ____ which will form into the ____ (primitive throat).
- Primitie pharynx
- Oropharnx
The 2 posterior parts of the embryo, the ____ and ____ form the rest of the mature pharynx as well as the remainder to the digestive tract.
- Midgut
- Hindgut
This is the branchial arch that forms the lower face, lip, mandible, muscles of mastication, trigeminal nerve, and tongue
Mandibular arch (Arch 1)
Arches ____ are involved in face and neck development.
2-6
The 1st arch is covered and lined with ____. The rest of the arches are covered with ____ and lined with ____.
- Ectoderm
- Ectoderm
- Endoderm
True/False:
The 5th branchial arch is so rudimentary that many times it is absent in humans or it is included within the 4th branchial arch.
True
Each arch contains a right and left ____ vessel that leads from the heart through the arches to the body. The 3rd arch vessles become he common ____ arteries. The 6th arche vessels become the ____ artery.``
- Aortic arch vessel
- Common carotid arteris
- Pulmonary artery
Between weeks 4-7 the ____ artery supplies the blood to the face, neck, and brain. However after the 7th week the face and neck ciculation shiits to the _____ and the ____ supplies only the brain at this time.
- Internal carotid artery
- External carotid artery
- Internal carotid artery
In weeks 5-7 muscles develope in the head and neck. Mastication muscles in the 1st arch include what?
- Masseter
- Mecdial & lateral pterygoid
- Temporalis
Which arch forms the facial muscles? Which arch forms the throat constrictor muscles?
- 2nd arch
- 3rd and 4th arch
By the end of the 7th week nerves have entered the facial muscle fibers. The 5th trigeminal nerve innervates the ____ arch, the 7th facial nerve innervates the ____ arch, the 9th glossopharyngeal nerve innervates the ____ arch, and the 10th vagus nerve innervates the ____ arch.
- 5th: 1st arch (facial sensation)
- 7th: 2nd arch (facial expression)
- 9th: 3rd arch (taste)
- 10th: 4th arch (pharynx motor muscle
The mandibular arch form from what cartilage?
Meckel's cartilage
The posterior mandibular arch's Meckel's cartilage forms what and what does it fuse with to form the ear.
- Malleus & incus form in the mandibular arch
- Fuse with the stapes from the 2nd arch to form ear
What are the 5 parts of the developing mandible?
- Alveolar
- Coronoid
- Condylar
- Angular
- Body
These are articulations of fibrous joints that unite surfaces. Named for the 2 or more bones they articulate. They also act as growth sites taht allow for bones to expand.
Sutures
What are 3 suture types?
- Simple
- Serrated (interdigitating)
- Squamosal (overlaping)
What are 4 sutures in the developing skull?
- Zygomaticomaxillary
- Zygomaticotemporal
- Pterygopalatine
- Frontomaxillary
What are the 4 processes/arches that develop the face during week 4?
- Frontal process: forehead
- Maxillary process: cheeks
- Mandibular arch: lower jaw
- Hyoid arch: face and neck
This will fuse together externall to form the middle part of the nose as well as what?
- Medial nasal process
- Forms philtrum of the upper lip
This will form the alae of the nose.
Lateral nasal process
This is the term denoted to describe the medial nasal process and the maxillary process connect and create a zome of fusion called the?
Nasal fin
When there is a failure of the maxillary process fusing with the medial nasal processes it can lead to _____. There can be varying degrees of disfigurment and disability, it can be either unilateral or bilateral.
Cleft lip
This is the groove separating the maxillar process form the lateral nasal process.
Naso-optic groove
This is the groove separating the maxillary process from the medial nasal process.
Bucconasal groove
This is the middle of the upper lip that is complete by what week?
- Medial nasal processes
- 6 week completed
The maxillary processes on each side of the mouth fuse with the mandibular arch to form the corners of the mouth. What are they called?
Commissures
The intermaxillary segment is involved int he formation of what 3 parts of the face?
- Maxillary incisors and associated tissues
- Primary palate
- Nasal septum
By weeks 7-9 these two processes have began to fuse to form the hard palate.
- Medial palatine (primary palate)
- Latral palatine
FYI: the lateral palatine processes develop from the maxillary tissues laterally and grow inward.
By what week is the palate complete to seperate the oral cavity and nasal cavities?
12 weeks
True/False:
The tongue does not help mold the processes of the palate together.
False: the tongue pushes up to help mold the processes together.
