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Questions and Answers
What is the initial structure that marks the beginning of tongue development?
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?
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?
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?
Which condition is known to result from an anomaly during the development of the tongue?
The merging of which structures contributes to the formation of the anterior part of the tongue?
The merging of which structures contributes to the formation of the anterior part of the tongue?
What type of mesodermal contribution is involved in the development of the tongue?
What type of mesodermal contribution is involved in the development of the tongue?
Which anatomical term describes a small eminence or tubercle associated with the early development of the tongue?
Which anatomical term describes a small eminence or tubercle associated with the early development of the tongue?
The development of the thyroid gland embryologically takes place in association with which structural elements?
The development of the thyroid gland embryologically takes place in association with which structural elements?
At what structure does the thyroid primordium originate?
At what structure does the thyroid primordium originate?
What is the fate of the thyroglossal duct during thyroid development?
What is the fate of the thyroglossal duct during thyroid development?
When does the thyroid gland reach its final anatomical position?
When does the thyroid gland reach its final anatomical position?
Which structure indicates the site of the thyroglossal duct in adults?
Which structure indicates the site of the thyroglossal duct in adults?
Which anatomical structure does the thyroid descend in front of during its development?
Which anatomical structure does the thyroid descend in front of during its development?
What is the nature of the thyroid primordium during its initial descent?
What is the nature of the thyroid primordium during its initial descent?
The thyroid gland remains connected to which structure until the fifth week?
The thyroid gland remains connected to which structure until the fifth week?
Which term describes a pouch or sac opening from a hollow organ, in the context of thyroid development?
Which term describes a pouch or sac opening from a hollow organ, in the context of thyroid development?
Which embryonic component contributes to the mucosa of the anterior 2/3 of the tongue?
Which embryonic component contributes to the mucosa of the anterior 2/3 of the tongue?
What is the name of the nerve responsible for general sensation in the anterior part of the tongue?
What is the name of the nerve responsible for general sensation in the anterior part of the tongue?
Which part of the tongue does the glossopharyngeal nerve innervate for taste sensation?
Which part of the tongue does the glossopharyngeal nerve innervate for taste sensation?
During tongue development, which structure is eliminated as a contributor to the definitive adult tongue?
During tongue development, which structure is eliminated as a contributor to the definitive adult tongue?
What is indicated by the terminal sulcus in the adult tongue?
What is indicated by the terminal sulcus in the adult tongue?
Which embryonic component is associated with the mucosa of the posterior 1/3 of the tongue?
Which embryonic component is associated with the mucosa of the posterior 1/3 of the tongue?
Which cranial nerve is responsible for special sensation related to taste appreciation in the anterior 2/3 of the tongue?
Which cranial nerve is responsible for special sensation related to taste appreciation in the anterior 2/3 of the tongue?
What aspect of tongue development does the hypobranchial eminence primarily influence?
What aspect of tongue development does the hypobranchial eminence primarily influence?
What is the final shape of the thyroid gland characterized by during the seventh week of development?
What is the final shape of the thyroid gland characterized by during the seventh week of development?
At what point does the thyroid begin to produce hormones during embryological development?
At what point does the thyroid begin to produce hormones during embryological development?
What do the follicular cells of the thyroid produce that serves as a source of thyroxine and triiodothyronine?
What do the follicular cells of the thyroid produce that serves as a source of thyroxine and triiodothyronine?
When do the first follicles containing colloid become visible in the developing thyroid gland?
When do the first follicles containing colloid become visible in the developing thyroid gland?
Which embryonic layer differentiates into thyroid follicular cells?
Which embryonic layer differentiates into thyroid follicular cells?
What structural component indicates the path taken by the thyroid gland during its descent?
What structural component indicates the path taken by the thyroid gland during its descent?
What critical function does thyroid hormone perform that is necessary during development?
What critical function does thyroid hormone perform that is necessary during development?
At what week does colloid begin to appear in the thyroid follicles?
At what week does colloid begin to appear in the thyroid follicles?
What is the primary function of parafollicular cells in the thyroid gland?
What is the primary function of parafollicular cells in the thyroid gland?
Where does the ectopic thyroid gland most commonly develop?
Where does the ectopic thyroid gland most commonly develop?
What are neural crest cells associated with regarding the thyroid gland?
What are neural crest cells associated with regarding the thyroid gland?
What is the common location of sublingual thyroid tissue in adults?
What is the common location of sublingual thyroid tissue in adults?
What hormone is primarily produced by parafollicular cells?
What hormone is primarily produced by parafollicular cells?
What does the term 'ectopic' refer to in the context of the thyroid gland?
What does the term 'ectopic' refer to in the context of the thyroid gland?
What is the role of calcitonin in the human body?
What is the role of calcitonin in the human body?
Which embryological structure is associated with the development of parafollicular cells?
Which embryological structure is associated with the development of parafollicular cells?
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.
