20 Pages in Head & Neck Anatomy

What structures develop from the maxillary process?

Lateral palatine processes (palatal shelves), upper part of cheeks, sides of upper lip

What structures develop from the mandibular process?

Lower jaw, lower part of face and lower lip, anterior tongue

What structures are derived from the 1st branchial arch?

Maxillary process and mandibular process

From which branchial arches does the posterior tongue develop?

2nd and 3rd branchial arches

At what week does facial development begin?

About week 3 of embryonic development

When is the upper lip completed?

Between weeks 6 and 8

How many processes fuse to form the upper lip?

Three processes

What three processes form the upper lip?

Median nasal process, right maxillary process, left maxillary process

When does the palate develop?

Between weeks 6 and 12

What structures fuse to form the palate?

Globular process with the left and right palatal shelves

In what direction do embryonic facial processes fuse?

Anterior to posterior

Why do clefts occur?

When embryonic processes fail to fuse completely

During which trimester do most facial malformations occur?

First trimester of pregnancy

What type of glands are salivary glands?

Exocrine glands (have ducts)

What nervous system stimulates saliva flow?

Parasympathetic nervous system

How many major pairs of salivary glands are there?

Three pairs

What percentage of total saliva comes from the submandibular gland?

65% (largest portion of saliva)

What duct is associated with the submandibular gland?

Wharton's duct

Where does Wharton's duct empty?

Under the tongue at the sublingual caruncle

What type of secretion does the submandibular gland produce?

Mixed secretion (mostly serous)

Where is the submandibular gland located?

Near the angle/body of the mandible

What cranial nerve provides parasympathetic innervation to the submandibular gland?

Cranial nerve VII (facial nerve)

What percentage of total saliva comes from the sublingual gland?

10%

What ducts drain the sublingual gland?

Ducts of Rivinus or Bartholin's ducts (8-20 ducts)

What type of secretion does the sublingual gland produce?

Mixed secretion (mostly mucous)

Where is the sublingual gland located?

Floor of the mouth near the midline

What cranial nerve provides parasympathetic innervation to the sublingual gland?

Cranial nerve VII (facial nerve)

Which two salivary glands share the same parasympathetic nerve supply?

Submandibular and sublingual glands (CN VII)

What percentage of total saliva comes from the parotid gland?

25%

What duct is associated with the parotid gland?

Stensen's duct

Where does Stensen's duct empty?

Opposite the maxillary molars

What type of secretion does the parotid gland produce?

Serous secretion only

What enzyme is found in parotid saliva and what does it do?

Amylase; breaks down starches

Where is the parotid gland located?

In front of and below the ears

What cranial nerve provides parasympathetic innervation to the parotid gland?

Cranial nerve IX (glossopharyngeal)

What bones form the temporomandibular joint?

Temporal bone and mandible

What fossa of the temporal bone is involved in the TMJ?

Mandibular (glenoid/articular) fossa

What structure lies just anterior to the mandibular fossa?

Articular eminence

What part of the mandible articulates with the temporal bone?

Condyle

What is the articular disc made of?

Fibrous pad of dense collagen tissue

Where is the articular disc thickest and thinnest?

Thick posteriorly, thin in the center

What does the articular disc divide the TMJ into?

Upper and lower synovial cavities

What is the TMJ capsule made of?

Thick fibrous tissue surrounding the joint

What ligament reinforces the TMJ capsule?

Temporomandibular joint (TMJ) ligament

What does the inner lining of the TMJ capsule secrete?

Synovial fluid

What is the function of synovial fluid?

Lubricates the joint

What do ligaments attach?

Bone to bone

What do tendons attach?

Muscle to bone

What type of movement is gliding or sliding?

Disk and condyle move forward and backward

What actions occur during gliding movement?

Protrusion and retrusion (retraction)

What type of movement is rotational or hinge movement?

Elevation and depression of the mandible

How does the TMJ disc move during normal function?

Moves in conjunction with the condyle

What muscles elevate the mandible?

Masseter, temporalis, medial pterygoid

What muscle depresses the mandible?

Lateral pterygoid

What muscle protrudes the mandible?

Lateral pterygoid

What muscle retrudes the mandible?

Temporalis

What muscle produces lateral shift of the mandible?

Lateral pterygoid

Which tooth has a mesial crown and root concavity?

Maxillary first premolar

Which premolar most often has two roots?

Maxillary first premolar

Which tooth has the longest root?

Maxillary canine

Which teeth most often fail to develop?

Third molar and maxillary lateral incisor

Which tooth has a non-functional lingual cusp?

Mandibular first premolar

Which tooth is most likely to exhibit lingual caries?

Maxillary lateral incisor

Which premolar commonly has three cusps?

Mandibular second premolar

Which tooth is most often affected by microdontia?

Maxillary lateral incisor (peg lateral)

What is the fundamental, functionally self-contained unit of the body?

The cell

What is the structure of the cell membrane?

Lipid bilayer with proteins

What is the function of the cell membrane?

Controls passage of materials in and out of the cell

What is the function of the nucleus?

Stores DNA and controls chemical reactions and synthetic activities

What is cytoplasm?

Watery gel enclosed by membrane containing organelles

Where do metabolic activities occur in the cell?

Cytoplasm

What is the function of lysosomes?

Contain digestive enzymes for cellular digestion; important in phagocytosis

What is the function of the Golgi apparatus?

Packaging and secretion of protein material

What is the function of mitochondria?

Energy production (ATP); powerhouse of the cell

What is the function of the endoplasmic reticulum?

Network of membranes for synthesis

What occurs in rough endoplasmic reticulum?

Protein synthesis due to ribosomes

What is the function of filaments and tubules?

Structural support for the cell

What does odontogenesis mean?

Origin and formation of teeth

What are the three embryonic layers?

Ectoderm, mesoderm, endoderm

What does ectoderm form?

Outer covering of body, oral cavity lining, enamel, nervous tissue

What does mesoderm form?

Skeletal and muscular systems and organs

What does endoderm form?

Epithelial linings of internal organs (stomach, intestines)

What is the stomodeum?

Primitive mouth that forms oral and nasal cavities

At what week does the stomodeum form?

Week 3

From what does tooth enamel form?

Ectoderm lining the stomodeum

What forms dentin, cementum, and pulp?

Ectomesenchyme (underlying connective tissue)

What occurs during the initiation stage?

Dental lamina forms from oral epithelium

What occurs during the bud stage?

Dental lamina grows into mesenchyme in 20 locations

What forms during the cap stage?

Enamel organ, dental papilla, and dental sac

What does the enamel organ form?

Enamel

What does the dental papilla form?

Pulp and dentin

What does the dental sac become?

PDL, cementum, alveolar bone

What occurs during the bell stage?

Cells increase and form bell shape

What are the four layers of the enamel organ?

OEE, stellate reticulum, stratum intermedium, IEE

What do inner enamel epithelial cells become?

Ameloblasts

What do ameloblasts form?

Enamel

What separates the IEE from the dental papilla?

Basement membrane

What cells form dentin?

Odontoblasts

During which stage does greatest differentiation occur?

Bell stage

What occurs during the apposition stage?

Layer-by-layer formation of tooth structure