Embryology Notes And Clinical Notes Flashcards
The pituitary gland develops from two soruce: ___ which grows superiorly from the roof of the stomodeum immediately anterior to the buccopharyngeal membrane, and a ______ which grows inferiorly from the floor of the diencephalon of the brain
a small ectodermal diverticulum (Rathke’s pouch)
Small ectodermal diverticulum (the infundibulum)
The rathke’s pouch develops during the ___ , and its connection with the oral epithelium elongates, narrows, and finally ___
2nd month of development
Disappears
Rathke’s pouch now is a vesicle that _____ itself around the anterior and lateral surfaces of the infundibulum.
Flattens
The cells of the anterior wall of the vesicle proliferate and form the _____ of the pituitary.
Pars anterior
A cellular extension from the vesicle’s upper part grows superiorly and around the stalk of the infundibulum, forming the _____
Pars tuberalis
The cells of the posterior wall of the vesicle never develop extensively; they form the?
Pars intermedia
the infundibulum differentiates into the ____ and ____ of the pituitary gland.
Stalk, pars nervosa
thyroid gland is invest in what fascia?
pretracheal fascia
the reason why thyroid gland tethers to the larynx and trahea in swallowing
because the thyroid gland is invested in the pretracheal fascia.
The close relationship between the trachea and the lobes of the thyroid
gland commonly results in pressure on the ____ in patients with
pathologic enlargement of the thyroid.
trachea
The attachment of the _ muscle to the thyroid cartilage
effectively limits upward expansion of the gland.
sternothyroid muscle
can compress the trachea and cause dangerous dyspnea; it can also cause severe venous compression.
retrosternal goiter
Damage to the external laryngeal nerve results in an inability to tense
the ____ and in _____.
vocal folds, hoarseness
superior thyroid A is related to what nerve? This nerve supplies what?
External laryngeal nerve
supplies cricothyroid muscle
The terminal branches of the inferior thyroid artery on each side are related to what nerve
recurrent laryngeal nerve
The parathyroid glands are usually four in number and are closely related to
the _____ of the thyroid gland
posterior surface
the posterior part of the thyroid gland is left undisturbed so that the parathyroid glands are not damaged. The development of the inferior parathyroid glands is closely associated with the thymus. For this reason, it is not uncommon for the surgeon to find the inferior parathyroid glands in the superior mediastinum because they have been pulled down into the thorax by the thymus.
partial thyroidectomy
The thyroid gland begins to develop during the ____ as an entodermal
thickening in the midline of the floor of the pharynx between the
_____ and the _____ Later, this thickening becomes a diverticulum, the ______ , that grows inferiorly into the underlying mesenchyme.
3rd week
tuberculum impar and the copula
thyroglossal duct
In what week does the thyroid gland reaches its final position in relation to the larynx and trachea
7th week
The site of origin of the thyroglossal duct on the tongue remains as a pit called the ____
Foramen cecum
The thyroid gland may now be divided into a small median _____ and two large lateral ____
Isthmus
Lobes
By the 3rd month, colloid starts to accumulate in the center of each cluster so that ___form
Follicles
The _____ and connective tissue develop from the surrounding mesenchyme.
Fibrous capsule
In which pharyngeal pouch is the ultimobranchial bodies?
Fifth pharyngeal pouch
The ____ (from the fifth pharyngeal pouch) and neural crest cells are believed to be incorporated into the thyroid gland, where they form the _____ , which produce ____.
Ultimobranchial bodies
Parafollicular cells
Calcitonin
Failure of development of the thyroid gland may occur and is the commonest cause of?
Cretinism
__ is the most common form of incomplete descent
Lingual thyroid
Conditions related to a persistence of the thyroglossal duct usually appear in ?
Childhood, adolescence, or in young adults
Ectopic thyroid tissue is occasionally found in the ____ in relation to the trachea or bronchi or even the esophagus.
Thorax
Cyst may occur most commonly in the region below the ____
Hyoid bone
Why does thyroglossal cyst should be removed surgically
Because remnants of the duct often traverse the body of the hyoid bone, this may have to be excised also to prevent recurrence
The thyroglossal cyst occupies the ___ and develops as a result of persistence of a small amount of epithelium that continues to secrete mucus.
Midline
A thyroglossal cyst ruptures spontaneously, producing a?
Thyroglossal sinus (fistula)
The pair of ______ develop as the result of proliferation of entodermal cells in the third pharyngeal pouch on each side
Inferior parathyroid glands (parathyroid III)
The pair of _____ develop as a proliferation of entodermal cells in the fourth pharyngeal pouch on each side.
Superior parathyroid glands (parathyroid IV)
In the earliest stages of the development of the parathyroid gland, each gland consists of a solid mass of clear cells, the chief cells. In late childhood, acidophilic cells, the ____, appear.
Oxyphil cells
The oxyphil cells are thought to be _____.
Nonfunctioning chief cells
It is believed that the parathyroid hormone is secreted early in fetal life by the chief cells to regulate?
Calcium metabolism
Agenesis or incomplete development of the parathyroid glands has been demonstrated in individuals with?
Idiopathic hypoparathyroidism
If the parathyroid glands remain attached to the thymus, they may be pulled inferiorly into the lower part of the neck or thoracic cavity.
Ectopic parathyroid glands
