Tongue Development and Nerve Supply

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Questions and Answers

What is the initial structure that marks the beginning of tongue development?

Foramen caecum

Pharyngeal arches

Lateral lingual swellings

Median swelling (Tuberculum Impar) (correct)

Which embryonic structure is predominantly responsible for the formation of the anterior two-thirds of the tongue?

Second pharyngeal arch

First pharyngeal arch (correct)

Thyroid gland

Foramen caecum

The posterior one-third of the tongue is mainly associated with which pharyngeal arches?

Third and fourth

First and third

First and second

Second, third, and fourth (correct)

Which condition is known to result from an anomaly during the development of the tongue?

Tongue-tie Signup and view all the answers

The merging of which structures contributes to the formation of the anterior part of the tongue?

Lateral lingual swellings Signup and view all the answers

What type of mesodermal contribution is involved in the development of the tongue?

Mesodermal proliferation Signup and view all the answers

Which anatomical term describes a small eminence or tubercle associated with the early development of the tongue?

Tuberculum Impar Signup and view all the answers

The development of the thyroid gland embryologically takes place in association with which structural elements?

Pharyngeal arches 2, 3, and 4 Signup and view all the answers

At what structure does the thyroid primordium originate?

Foramen cecum Signup and view all the answers

What is the fate of the thyroglossal duct during thyroid development?

It breaks down and may form a thyroglossal cyst. Signup and view all the answers

When does the thyroid gland reach its final anatomical position?

At the end of the seventh week Signup and view all the answers

Which structure indicates the site of the thyroglossal duct in adults?

Foramen cecum Signup and view all the answers

Which anatomical structure does the thyroid descend in front of during its development?

Laryngeal cartilages Signup and view all the answers

What is the nature of the thyroid primordium during its initial descent?

A bilobed thyroid diverticulum Signup and view all the answers

The thyroid gland remains connected to which structure until the fifth week?

Thyroglossal duct Signup and view all the answers

Which term describes a pouch or sac opening from a hollow organ, in the context of thyroid development?

Diverticulum Signup and view all the answers

Which embryonic component contributes to the mucosa of the anterior 2/3 of the tongue?

1st arch Signup and view all the answers

What is the name of the nerve responsible for general sensation in the anterior part of the tongue?

Lingual nerve Signup and view all the answers

Which part of the tongue does the glossopharyngeal nerve innervate for taste sensation?

Posterior 1/3 Signup and view all the answers

During tongue development, which structure is eliminated as a contributor to the definitive adult tongue?

Copula Signup and view all the answers

What is indicated by the terminal sulcus in the adult tongue?

Division between anterior and posterior parts Signup and view all the answers

Which embryonic component is associated with the mucosa of the posterior 1/3 of the tongue?

3rd arch Signup and view all the answers

Which cranial nerve is responsible for special sensation related to taste appreciation in the anterior 2/3 of the tongue?

Facial nerve Signup and view all the answers

What aspect of tongue development does the hypobranchial eminence primarily influence?

Development of the pharyngeal part Signup and view all the answers

What is the final shape of the thyroid gland characterized by during the seventh week of development?

An isthmus with two lateral lobes Signup and view all the answers

At what point does the thyroid begin to produce hormones during embryological development?

Week 10-12 Signup and view all the answers

What do the follicular cells of the thyroid produce that serves as a source of thyroxine and triiodothyronine?

Colloid Signup and view all the answers

When do the first follicles containing colloid become visible in the developing thyroid gland?

End of the third month Signup and view all the answers

Which embryonic layer differentiates into thyroid follicular cells?

Endoderm Signup and view all the answers

What structural component indicates the path taken by the thyroid gland during its descent?

Thyroglossal duct Signup and view all the answers

What critical function does thyroid hormone perform that is necessary during development?

Proper brain development Signup and view all the answers

At what week does colloid begin to appear in the thyroid follicles?

Week 11 Signup and view all the answers

What is the primary function of parafollicular cells in the thyroid gland?

Secrete calcitonin to regulate calcium levels Signup and view all the answers

Where does the ectopic thyroid gland most commonly develop?

Along the path of descent from the tongue Signup and view all the answers

What are neural crest cells associated with regarding the thyroid gland?

Differentiation into parafollicular cells Signup and view all the answers

What is the common location of sublingual thyroid tissue in adults?

Just inferior to the hyoid bone Signup and view all the answers

What hormone is primarily produced by parafollicular cells?

Calcitonin Signup and view all the answers

What does the term 'ectopic' refer to in the context of the thyroid gland?

Thyroid tissue located in an abnormal position Signup and view all the answers

What is the role of calcitonin in the human body?

Decrease calcium levels in the blood Signup and view all the answers

Which embryological structure is associated with the development of parafollicular cells?

Pharyngeal pouch 4 (ultimobranchial body) Signup and view all the answers

Study Notes

Development of the Tongue

The anterior two-thirds (oral part) of the tongue develops from three swellings:
- One median swelling: Tuberculum Impar
- Two lateral lingual swellings
All three swellings originate from the first pharyngeal arch.
Lateral lingual swellings merge and overgrow the median swelling, forming the anterior two-thirds of the tongue
The posterior one-third (pharyngeal part) of the tongue develops from two elevations caudal to the foramen cecum.
The pharyngeal part of the tongue develops from the hypobranchial eminence, eliminating any contribution from the second arch.
The line of fusion between the oral and pharyngeal parts of the tongue is marked by the terminal sulcus.

Nerve Supply of the Tongue

The oral part of the tongue receives general sensation from the lingual nerve (mandibular division of the trigeminal nerve)
The oral part also receives taste sensation from the chorda tympani (facial nerve) except for the vallate papillae.
The pharyngeal part of the tongue receives general sensation from the glossopharyngeal nerve.

Congenital Anomaly of the Tongue

Tongue-tie: A congenital anomaly where the frenulum linguae (a fold of tissue connecting the underside of the tongue to the floor of the mouth) is too short or tight, restricting tongue movement.

Development of the Thyroid Gland

The thyroid gland originates as an endodermal proliferation at the tip of the foramen cecum and descends inferiorly.
It remains connected to the tongue by the thyroglossal duct until the fifth week.
The thyroglossal duct typically disappears by the end of the fifth week, but may persist as a pyramidal lobe or thyroglossal cyst.
The thyroid gland reaches its final position in front of the trachea in the seventh week.
The endoderm of the thyroid primordium differentiates into follicular cells, which produce thyroxine and triiodothyronine.
The thyroid gland begins to function around the end of the third month, when the first follicles containing colloid become visible.
Thyroid function is essential for proper brain development.
Neural crest cells within the ultimopharyngeal body (pharyngeal pouch 4) differentiate into parafollicular cells (C cells) within the thyroid gland.
Parafollicular cells secrete calcitonin, which regulates calcium levels in the blood.

Ectopic Thyroid Gland

An ectopic thyroid gland is located along the normal route of descent from the tongue.
The most common type is lingual thyroid glandular tissue.
Sublingual thyroid gland is another type, located at or just inferior to the hyoid bone.

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Description

Explore the intricate development and nerve supply of the tongue. This quiz covers the origins of the anterior and posterior parts of the tongue, their structural evolution from the pharyngeal arch, and the sensory innervation involved. Test your knowledge on these fundamental aspects of human anatomy.