Overview of pharynx and larynx Flashcards
What is the pharynx?
The cranial end of the foregut
What are the boundaries and extensions of the pharynx?
Extends from the base of the skull to inferior border of the cricoid cartilage.
- Continous with the esophagus
- Develops rom Va
What is the Pharynx developed from and composed of?
Develop from vagal somites and composed of striated muscles.
The pharynx is subdivided into what?
- Nasopharynx between the base of the skull and palate
- Oropharynx below palate and above hyoid
- Laryngopharynx below oropharynx and cricoid.
- -Where trachea evaginates from the gut
Function of pharynx?
acts as a common tube for food and air
What is the pharynx area perforated into and supported by in other vertebrates?
Its perforated by gill slits and supported by pharyngeal arches.
- In humans pouches and clefts form but do not perforate.
- Arches are modified to form skeleton of pharynx and larynx
What is the pharyngeal skeleton?
modified gill arches each modified with:
- Cartilagenous or bony arch
- cranial nerve
- an aortic arch
What does the first arch form and what nerve supplies it?
Forms the jaw, malleus and incus. supplied by CN V
What do the 1st pouch and cleft forms?
Auditory tube, middle ear/ external auditory meatus.
What does the second arch forms? what nerves supply it?
stapes, styloid process, styloid ligament, lesser horns of hyoid supplied by CN VII
2nd pouch forms:
The palatine tonsil
3rd arch forms what? supplied by what nerve?
Body of greater horn of hyoid. Nerve supply by CN IX
3rd pouch forms?
Thymus and inferior parathyroid
4th arch forms? supplied by what nerve?
4th arch forms the thyroid cartilage and is supplied by CN X
4th pouch forms:
4th pouch forms the superior parathyroid.
5th arch forms? supplied by what nerve?
Laryngeal cartilage and supplied by CN X
5th pouch forms:
ultimobanchial body (May contribute to thyroid)
6th arch forms:
Arytenoids, cricoid and tracheal ring and its supplied by CN X
What is the Larynx?
Cartilagenous and bony superstructure supporting and protecting a sphincter (Vocal Cords) separating air passage from gut.
What does the larynx functions primarily as?
a guard to airway and secondary vocalization
How are the food and fluid preventing from going down the ventral tube (Glottis)?
- Via a sphincter which is attached to cup-shaped cartilages (Arytenoids)
- In front of ring-shaped cartilages (Cricoids)
- -maintains the patency of mouth of trachea
- Mammals add shield-shaped thyroid cartilage and epiglottis
