Lecture 17: Introduction to the GI System

What is the stomatodeum? What is it lined with/derived from?

Primitive oral cavity

Surface ectoderm

What is the primitive pharynx lined with?

Endoderm

How are the stomatodeum and primitive pharynx separated early in development?

Buccopharyngeal membrane

This disappears after 3 weeks of development

What is the oral junction of the ecto and endoderm?

Oral fauces

Note that the pharynx is the start of the endoderm

What is the primitive gut tube lined with?

Endoderm

Are the pharynx and esophagus included in the foregut?

Yes!

What is the primary function of the pharynx?

Swallowing

What is the primary function of the esophagus?

Transportation and propulsion of the bolus

What is the buccal vestibule?

Space between cheeks and gums (posterior teeth)

What is the labial vestibule?

Space between lips and gums (anterior teeth)

What forms the floor of the oral cavity?

Mylohyoid muscle

What forms the posterior border of the mouth?

Fauces

The palatoglossal arch is found ____ to the palatopharyngeal arch.

Anterior

What is found between the palatoglossal arch and palatopharyngeal arch?

Palatine tonsils

What tonsils make up waldeyer’s ring?

Adenoids

Tubal tonsils

Palatine tonsils

Lingual tonsils

What tonsils are found in the nasopharynx?

Adenoids (pharyngeal tonsils)

Tubal tonsils

What tonsils are found in the oropharynx?

Palatine tonsils

Lingual tonsils

Medial sulcus

Divides tongue down middle

Terminal sulcus

Divides anterior from posterior tongue

Foramen cecum

Depression at the terminal sulcus (remnant of thyroglassal duct where the thyroid develops)

Lingual tonsils

Cover posterior 1/3 of tongue

What are the intrinsic muscles of the tongue?

Longitudinal

Vertical

Transverse

What CN help with taste?

7, 9, 10

Filiform papilla

Found on oral tongue

Not involved with taste

Most numerous

Foliate papillae

Lateral tongue

Fungiform papillae

across anterior tongue

taste

vallate papillae

at terminal sulcus!

What taste are vallate papillae best at sensing?

Bitter

Primary teeth are also called ____.

Deciduous teeth

Deciduous teeth erupt at ____.

6-30 months

Permanent tooth replacement begins at ____.

6 years old with M1

The upper teeth are generally innervated by

CN V2 (superior alveolar nerve)

The lower teeth are generally innervated by

CN V3 (inferior alveolar nerve)

The parotid duct is also called

stensens’s duct

What muscle does the parotid duct pierce? Where does it open into?

Buccinator

The buccal vestibule at the parotid papilla across from M1

The sublingual fold marks the position of the ____ gland

sublingual

The submandibular duct is called ____

Wharton’s duct

Where does the submandibular duct open into the oral cavity?

sublingual caruncle

Where do the sublingual and submandibular glands drain into?

Wharton’s duct

T/F, there are submucosal salivary glands all over the mouth

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