Development of Midline Structures Flashcards
Where does the pituitary gland sit?
In the sella turcica, or pituitary fossa, of the sphenoid bone
What is the pituitary gland made up of?
Anterior and posterior lobe
What is the anterior lobe of the pituitary gland also known as?
Adrenohypophysis
What is the embryological origin of the anterior lobe of the pituitary gland?
Ectoderm
What kind of tissue is the anterior lobe of the pituitary gland?
Endocrine
What is Rathke’s pouch?
Idk jono wasn’t very clear
What is the posterior lobe of the pituitary also known as?
Neurohypophysis
What is the embryological origin of the posterior lobe of the pituitary?
Neuroectoderm
What kind of function does the posterior lobe of the pituitary have?
Neuroendocrine
What is the infundibulum?
Idk
How are the embryological origins of the anterior and posterior pituitary gland related?
They have entirely separate embryological origins, which later become structurally and functionally linked.
What is the posterior pituitary gland derived from?
The developing brain
What is the first step in the development of the posterior lobe of the pituitary gland from the developing brain?
A down-growth from the dicephalon forms in the midline, called the infundibulum
What happens to the part of the dicephalon from which the infundibulum arises as development proceeds?
It becomes the floor of the hypothalamus
What does the connection between the dicephalon and infundibulum become?
The pituitary stalk
Where does the infundibulum extend?
Down towards the roof of the developing oral cavity
What does the infundibulum retain when it extends down towards the roof of the oral cavity?
It’s connection with the brain
How does the infundibulum retain its connection to the brain?
By the pituitary stalk
What develops in the pituitary stalk?
Nerve fibre tracts
How do nerve fibre tracts develop in the pituitary stalk?
They grow down from the hypothalamus
What happens simultaneously to the infundibulum forming?
An out-pouching from the roof of the oral cavity grows up to meet the infundibulum
What is the out-pouching that pushes out from the roof of the oral cavity to meet the infundibulum known as?
Rathke’s pouch
What happens to Rathkes pouch once it has met the infundibulum?
It loses its connection with the roof of the mouth
Where does Rathke’s pouch come to lie?
Anterior to the infundibulum, and wrapped around the pituitary stalk
What happens to the cells of Rathke’s pouch?
They differentiate into the endocrine cells of the anterior pituitary
What functionally links the anterior lobe and posterior lobe of the hypothalamus?
A network of blood vessels, the hypophyseal portal system
What may persistent remnants of Rathke’s pouch form?
Cysts
When does the tongue appear in development?
4th week
What does the appearance of the tongue in development coincide with?
It is about the same time as the palate begins to form
What appears first in development of the tongue?
Two lateral lingual swellings
Three medial lingual swellings
What are the lateral lingual swellings derived from?
1st pharyngeal arch
What are the medial lingual swellings derived from?
1st, 2nd, 3rd, and 4th pharyngeal arch
What part of the tongue is derived from the 1st pharyngeal arch portion of the medial lingual swellings?
Tuberculum impar
What part of the tongue is derived from the 2nd and 3rd pharyngeal arch portion of the medial lingual swellings?
Cupola
What part of the tongue is derived from the 4th pharyngeal arch portion of the medial lingual swellings?
Epiglottal swelling