Pituitary Gland Flashcards
What two lobes form the pit gland?
Anterior and posterior
What kind of cells is the anterior pit made up of?
Glandular
What kind of cells is the posterior pit made up of?
Neuronal (axons mainly)
What hormones does the anterior pit secrete?
Growth Hormone Follicle stimulating Hormone ACTH Thyroid stimulating hormone Prolactin Luteinizing hormone
What hormones does the posterior pit secrete?
ADH
Oxytocin
Where is the pit gland located?
In the pit fossa.
Below the hypothalamus and above the sella turcica of the sphenoid bone.
What surrounds the pit gland?
Cavernous sinuses (R and L).
What links the R and L cavernous sinuses?
Anterior intercavernous sinus
What forms the lateral border of the cavernous sinuses?
Dura mater
What is the dura mater?
A meningi that forms the floor of the cranial fossae.
What is the diaphragm sellae?
Part of the dura mater that coverers the pit fossa
What coverers the pit fossa?
Diaphragm sellae from dura mater.
What is the main content of the cavernous sinuses?
Venous blood vessels that drain into the internal jugular vein
Where do the venous blood vessels in the cavernous sinus drain into?
Internal jugular vein
What six points of interest can be seen in the cavernous sinuses?
Internal carotid artery Oculomotor (CNIII) Trochlear (CNIV) Abducens (CNVI) Ophthalmic and maxillary divisions of trigeminal (CNV1+2)
List the 4 lateral cranial nerves in the cavernous sinuses from superior to inferior.
Oculomotor (CNIII)
Trochlear (CNIV)
Ophthalmic division of trigeminal (CNV1)
Maxillary division of trigeminal (CNV2)
What can be found directly above the pit gland?
Optic chiasm
What is the optic chiasm?
Where the optic (CNII) nerves cross.
Where is the optic chiasm located?
Directly above the pit gland.
What links the posterior pit to the hypothalamus?
Infundibulum
What are the two options for approaching the pit gland for surgery?
Transcranial- Subfrontal lobe
Transsphenoid- Via nasal cavity and sphenoid sinuses
What bones need broken when accessing the pit gland via the transsphenoid route?
Separation of nasal septum (+/- Le Fort 1)
Floor and roof of sphenoid sinuses
What bones make up the nasal cavity?
Vomer
Ethmoid
What are the four paranasal sinuses?
Frontal
Maxillary
Ethmoid air
Sphenoid
What is the function of the optic chiasm?
Conducts AP bilaterally from nasal retinae
How does functional deficit of optic chiasm present?
Bitemporal hemianopia
What is the function of the oculomotor nerve?
Motor movement of eye
Sphincter of iris
How does a problem with the oculomotor nerve present?
Problems with eye movement
Dilated pupils
What does the trochlear nerve do?
Depresses eye
How do problems with the trochlear nerve present?
Inability to look inferior and laterally
What does the trigeminal do?
Sensory to most of face
Motor to muscles of mastication
How does damage to the trigeminal nerve present?
Sensory loss of face
Inability to chew