18 Questions
What is the internal covering of the mesenchyme core in the pharyngeal arches?
Endoderm
What arises from the truncus arteriosus of the primordial heart in the pharyngeal arches?
An artery
What is the fate of the middle part of Meckel's cartilage?
It regresses and forms the anterior ligament of malleus and the sphenomandibular ligament
What forms the skeleton of the pharyngeal arch?
A cartilaginous rod
What nerve divisions arise from the first pharyngeal arch?
Maxillary and mandibular divisions
What is the process by which the bony mandible forms from the first pharyngeal arch?
Intramembranous ossification
Which pharyngeal arch gives rise to the maxillary artery?
First pharyngeal arch
What is the main component of the second pharyngeal arch that forms the styloid process?
Reichert's cartilage
Which pharyngeal arch gives rise to the vagus nerve?
Sixth pharyngeal arch
What is the main function of the pharyngeal pouches?
To form the endodermal evaginations from the lateral walls lining the pharynx
Which pharyngeal arch gives rise to the thyroid cartilage and epiglottis?
Fourth pharyngeal arch
What is the main component of the first pharyngeal arch that forms the oral epithelium?
Ectodermal lining
What is the characteristic feature of the dorsal surface of the tongue due to the presence of filiform papillae?
Rough texture
During embryonic development, how many pairs of pharyngeal arches are visible externally by the end of the fourth week?
Four pairs
What is the result of the overgrowth of filiform papillae?
Hairy tongue
What is the orientation of the arrangement of filiform papillae on the anterior two-thirds of the tongue?
In 'V'-shaped rows
What is the lining of the pharyngeal grooves?
Ectoderm
What is the characteristic of filiform papillae histologically?
More keratinization
Study Notes
Folate Papillae
- Threadlike, pointed structures containing tactile receptors
- Thin, pointy projections (small cones) giving the tongue’s dorsal surface its characteristic rough texture
Filiform Papillae
- Arranged in "V"-shaped rows paralleling the sulcus terminalis on the anterior two-thirds of the tongue
- Histologically show more keratinization than the other papillae
- Overgrowth results in hairy tongue, loss results in glossitis
Pharyngeal Arches
- Six pairs of U-shaped bars that appear inferior to the stomodeum during the fourth week of embryonic development
- Bordered medially by the pharynx
- First pair appears as surface elevations lateral to the developing pharynx
- Other arches appear as obliquely disposed, rounded ridges on each side of the future head and neck regions
- Contribute to the formation of the lower head and neck
- Separated from each other by ectodermlined pharyngeal grooves and internally lined by endodermal lined branchial pouches
First Pharyngeal Arch
- Artery becomes the maxillary artery which supplies the derivatives of the first pharyngeal arch
- Ectodermal lining of the first arch gives rise to the oral epithelium
Second Pharyngeal Arch
- Musculature: Reichert’s cartilage
- Intermediate part forms the stylohyoid ligament
- Ventral part forms lesser cornu and the superior part of the body of the hyoid bone
- Cranial nerve component: Stapes and portions of malleus and incus
- Dorsal part forms the styloid process
- Artery: Hyoid artery and stapedial artery which supply derivatives of the 2nd pharyngeal arch
Third Pharyngeal Arch
- Musculature: Third arch cartilage
- Greater cornu of the hyoid bone and the lower half of the body of the hyoid bone
- Cranial nerve component:
- Arterial component: Common carotid and roots of the internal carotid arteries
Fourth Pharyngeal Arch
- Skeletal components: Thyroid cartilage and epiglottis
- Musculature:
- Cranial nerve component: Vagus nerve
- Arterial component: Left side - part of the arch of the aorta, Right side - proximal portion of the right subclavian artery
Fifth Pharyngeal Arch
- Not visible on the surface of the embryo
Sixth Pharyngeal Arch
- Musculature:
- Skeletal components: Laryngeal cartilages (except thyroid and epiglottis)
- Cranial nerve component: Vagus nerve
- Arterial component:
Pharyngeal Pouches
- Five pairs of endodermal evaginations from the lateral walls lining the pharynx
- Balloon-like structures in a craniocaudal sequence between the branchial arches
Test your knowledge of pharyngeal arches, including their components, development, and the structures they give rise to. Learn about the mesenchyme core, artery, nerves, and skeletal components of pharyngeal arches. This quiz covers the key aspects of pharyngeal arches in embryonic development.
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