Second arch
The second pharyngeal arch or hyoid arch, is the second of fifth pharyngeal arches that develops in fetal life during the fourth week of development and assists in forming the side and front of the neck.
What are the derivatives of second pharyngeal arch?
Second branchial arch:
Arch: stapes, the body of the hyoid, lesser horn of hyoid, muscles of facial expression, and CNVII. Pouch: palatine tonsil. Nerve: facial nerve (CN VII)
What does the 2nd branchial arch form?
The second branchial arch cartilage produces the stapes, the styloid process, the stylohyoid ligament, and the superior portion of the body of the hyoid. The other branchial arch cartilages contribute to the inferior portion of the hyoid as well as the thyroid cartilage.
What develops from the second pharyngeal pouch?
The second pharyngeal pouch develops into the palatine tonsils, a secondary lymphoid organ playing a role in protecting the body from pathogens passing through the pharynx. The third pharyngeal pouch develops into the thymus and inferior portion of the parathyroid.
What is a pharyngeal arch?
Anatomy: Pharyngeal arches are paired structures that grow on either side of the future head and neck of the developing embryo and fuse at the centerline. … Pharyngeal arches produce the cartilage, bone, nerves, muscles, glands, and connective tissue of the face and neck.
How many pairs of pharyngeal arches are there?
Pharyngeal arches, pouches, and clefts. There are five pairs of pharyngeal arches, numbered 1, 2, 3, 4, and 6 for comparative embryology reasons.
What are the derivatives of the first pharyngeal arch?
The first pharyngeal arch–derived maxillary prominences fuse to form the intermaxillary segment which gives rise to the following oral cavity structures: philtrum of the lip, the maxilla and incisors, and the primary palate.
What is the function of the branchial arch?
branchial arch, also called Visceral Arch, or Gill Arch, one of the bony or cartilaginous curved bars on either side of the pharynx (throat) that support the gills of fishes and amphibians; also, a corresponding rudimentary ridge in the embryo of higher vertebrates, which in some species may form real but transitory …
How do pharyngeal arches form?
Pharyngeal arches are formed by cells that are derived from ectoderm, endoderm, mesoderm and neural crest. Ectoderm lines the external surfaces of the pharyngeal arches. The ectodermally lined depressions between the pharyngeal arches are called pharyngeal grooves.
What is a pharyngeal pouch?
A pharyngeal pouch, also known as Zenker’s diverticulum, occurs when part of the pharyngeal lining herniates through the muscles of the pharyngeal wall. This occurs mainly in older people. Presenting symptoms include dysphagia, regurgitation of undigested food, halitosis, hoarseness, and chronic cough.
What are pharyngeal clefts?
The pharyngeal clefts are ectodermal-lined recesses that appear on the OUTSIDE of the pharnyx between the arches; cleft 1 is between arch 1 and 2, cleft 2 is between arches 2 and 3, etc.
Which pharyngeal arch makes the thyroid?
The thyroid initially arises caudal to the tuberculum impar, which is also known as the median tongue bud. This embryonic swelling develops from the first pharyngeal arch and occurs midline on the floor of the developing pharynx, eventually helping form the tongue as the two lateral lingual swellings overgrow it.
Where does pharyngeal pouch occur?
A pharyngeal pouch (also called Zenker’s diverticulum) is a small bulge or pocket, like a hernia, that occurs in the pharynx. The term ‘pharyngeal’ refers to the pharynx, the part of your throat that connects the mouth, nose and oesophagus – it runs from behind your nose through to the bottom of your neck.
What pharyngeal pouch does thyroid come from?
The thyroid originates between the first and second pharyngeal pouches near the base of the tongue. In the third week of gestation, around day 20-24, endodermal cells of the primitive pharynx proliferate, creating the thyroid diverticulum.
What is primitive pharynx?
Primitive Pharynx – the cranial portion of the foregut. Craniocaudal-from the front of the embryo (cranio) to the back of the embryo (caudal) Diverticulum – an outpocketing. … Pharyngeal arches are homologous with the branchial arch system of fish and larval amphibians.
What are the pharyngeal muscles?
The pharyngeal muscles are a group of muscles that form the pharynx, which is posterior to the oral cavity, determining the shape of its lumen, and affecting its sound properties as the primary resonating cavity. The pharyngeal muscles (involuntary skeletal) push food into the esophagus.
What are visceral arches?
Visceral arches are pieces of cartilages or bones that support the pharyngeal region of vertebrates and also help attach the jaws with the skull. The visceral arches are also known as pharyngeal arches.
Do humans have aortic arches?
The aortic arches or pharyngeal arch arteries (previously referred to as branchial arches in human embryos) are a series of six paired embryological vascular structures which give rise to the great arteries of the neck and head. They are ventral to the dorsal aorta and arise from the aortic sac.
What is the Stylopharyngeus muscle?
The stylopharyngeus muscle is a long, slender and tapered longitudinal pharyngeal muscle that runs between the styloid process of the temporal bone and the pharynx and functions during the pharyngeal phase of swallowing.
Which arch contributes to the anterior 2/3 of the tongue?
This merging leads to the formation of the anterior two-thirds of the tongue. Since the mucosa overlying this area of the tongue has its origin from the first pharyngeal arch; it receives its sensory innervation from the mandibular branch of the V cranial nerve (trigeminal nerve).
What is the mandibular arch?
Medical Definition of mandibular arch
: the first branchial arch of the vertebrate embryo from which in humans are developed the lower lip, the mandible, the masticatory muscles, and the anterior part of the tongue.
Which organisms develop gills from pharyngeal arches?
In fishes and larvae of amphibians, these clefts develop gills and become respiratory organs. Pharyngeal pouches develop in the early embryos of all vertebrates, including the air-breathing terrestrial reptiles, birds, and mammals.
Do lizards develop gills from pharyngeal arches?
As gills are the primitive condition of vertebrates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arches varies between taxa. … In amphibians and reptiles, many elements are lost including the gill arches, resulting in only the oral jaws and a hyoid apparatus remaining.
Do snakes have pharyngeal arches?
The pattern in snakes suggests developmental dissociation of dorsal and ventral splanchnic derivatives and extensive topological rearrangements of some ventral pharyngeal arch derivatives typical of most tetrapods. When snakes swallow large prey, the effective oral cavity becomes extremely short ventrally.
How did the pharyngeal gill arches evolve?
Thus, the key to the development and evolution of the vertebrate pharyngeal arches is the establishment of endodermal outpocketing and subsequent epithelial influence on the fate of the neural crest cells that fill these segments to direct them to generate ectomesenchymal derivatives.
What is painful swallowing called?
“Odynophagia” is the medical term for painful swallowing. Pain can be felt in your mouth, throat, or esophagus. You may experience painful swallowing when drinking or eating food. Sometimes swallowing difficulties, known as dysphagia, can accompany the pain, but odynophagia is often a condition of its own.
Why do I have a pocket in my throat?
It is believed that the internal pressure produced by the esophagus to move food into the stomach can herniate the esophageal lining through a weakened wall, creating a pouch or a diverticulum. There is usually distal end obstruction.
What causes a neck pouch?
Anatomy. A pharyngeal pouch or Zenkers Diverticulum is an outpouching of the pharynx at the level of the larynx (voice Box). Pouches occur in older people and are the result of fibrosis of a band of muscle at the top of the oesophagus callled cricopharyngeus.
Which pharyngeal arch is associated with Treacher Collins syndrome?
Treacher Collins syndrome (TCS, also known as Mandibulofacial Dysotosis or Franceschetti-Klein syndrome) affects the first and second pharyngeal arches. It presents clinically with bilateral Tessier Clefts 6, 7 and 8 and a hypoplastic mandible.
What is the fate of pharyngeal clefts and pouches?
In the embryonic development of vertebrates, pharyngeal pouches form on the endodermal side between the pharyngeal arches. The pharyngeal grooves (or clefts) form the lateral ectodermal surface of the neck region to separate the arches. The pouches line up with the clefts, and these thin segments become gills in fish.
How many pharyngeal membranes are there?
There are also four pharyngeal membranes and as mentioned above, these structures join the opposing clefts and pouches together.
What is a lingual thyroid?
Lingual thyroid is an abnormal mass of ectopic thyroid tissue seen in base of tongue caused due to embryological aberrancy in development of thyroid gland. Most of the ectopic tissue is seen in the tongue.
What are the causes of cretinism?
- Dietary iodine deficiency.
- Failure of responding to the iodine of thyroid hormone supplement.
- Maternal hypothyroidism.
- Exposure to radioactive iodine during pregnancy.
- Use of antithyroid drugs or sulfonamides during pregnancy.