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Development of the face and neck ch. 4

Terms in this set (46)

fourth week of development
Face and Neck development occur during the...
growing brain and bulging heart
During the 4th week (face and neck development), there is rapid development of the...
-Primitive mouth
-Mandibular arch
-Maxillary process
-Frontonasal process
-Nose
Facial structures
-Frontonasal process -1 (superior)
-Maxillary process -2 (bilateral)
-Mandibular process -2 (bilateral)
There are five processes of the development of the face:
(2 are paired, one single)
inferior direction
Frontonasal growth occurs in which direction?
anterior direction
Both bilateral maxillary and mandibular pairs grown in which direction?
Stomodeum
primitive mouth in embryo
fusion
Greatest percentage of facial growth occurs through...
Develop of swellings or tissue on the same surface of the embryo
-Different from palatal or mandibular symphysis fusion!
What are fusions in embryo formation?
mesenchyme
Cleft or furrow will disappear as ____________ infiltrates the ectodermal tissue (fusion)
Ectoderm
Creation of the Stomodeum and Oral cavity is from which layer?
-Ectoderm
-Oral Epithelium
What makes up the oropharyngeal membrane?
-Endoderm
-Digestive system
What makes up the Primitive pharynx?
Primitive pharynx
The oropharyngeal membrane disintegrates causing the stomodeum (primitive mouth) to be connected to:
Tissues of the mandible
What is the first to form after stomodeum?
Mandibular process
-first branchial arch (Meckel's Cartilage)
-Mandibular teeth
-Lower lips and face
-Tongue
-Muscles of mastication
Frontonasal process
forms upper portion of the face: forehead, eyes, nose, philtrum
-placodes
-medial and lateral processes
Sensory placode
platelike thickening of embryonic ectoderm from which a definitive structure develops
-lens
-otic
-nasal
Lens placodes
Placodes forming eyes and related tissue
Otic placodes
Placodes in embryo forming future internal ear
Nasal placodes
Placodes that develop the nasal fossa and olfactory system
-Nasal placode
-Oronasal Membrane
Nose and paranasal sinus formation
1. Medial nasal processes (external medial)
2. Intermaxillary segment (internal medial)
3. Lateral nasal processes
Three parts of the Oronasal membrane
Medial nasal process (external medial)
middle part of the tissue growing around nasal placodes located between nasal pit
-apex of nose
-tubercle of lip
-philtrum
Intermaxillary segment (internal medial)
Internal fusion of the medial nasal
-maxillary incisors- central and lateral
-primary palate (1/3 of hard palate)
-nasal septum
Lateral nasal process
tissue on outer part of nasal pits that forms ala of the nose
maxillary arch formation
Growth of the mandible stimulates...
Maxillary process
-secondary palate (2/3 of hard palate)
-soft palate and uvula
-canines, premolars, molars
upper lip and philtrum
the maxillary process fuses with the medial nasal process to produce the:
labial commissure
the maxillary process fuses with the mandibular process to produce the:
Cleft lip
Can be described as the failure of mesenchyme to grow beneath the ectoderm (failure of fusion of the medial nasal process and the maxillary process)
-can be unilateral or bilateral
Foregut, midgut, hindgut
The primitive gut is divided into three sections:
-(early digestive system)
foregut
Anterior part of future digestive tract or primitive pharynx that forms oropharynx
Midgut and hindgut
remainder of digestive track
pharyngeal pouches
LATERAL walls of digestive track form:
connects oral cavity (ectoderm) to pharynx (endoderm)
Loss of the oropharyngeal membrane:
branchial arches
stacked bilateral swellings of tissue
1st: Meckel's (mandible)
2nd: Reichert's (hyoid)
3rd: No name
4th and 6th: larynx
5th: missing/temporary rudimentary
6 Branchial arches:
1st branchial arch
-Meckel's cartilage
-Mandible
2nd branchial arch
-Reichert's cartilage
-Hyoid
5th branchial arch
Often absent of RUDIMENTARY
Branchial pouches
Balloon like structures between the branchial arches
-Auditory (1)
-Palatine Tonsils (2)
-Parathyroid (3-4)
Branchial Pouches (4)
-Tympanic membrane (1)
-All others are rudimentary
Branchial Grooves
Branchial cysts
Failure of grooves to disintegrate results in cells left behind which may develop into:
Congenital cysts
Also known as branchial cysts
-arise in the lateral aspect of the neck
-most common of congenital neck masses
-become noticeable much later in life
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