Pituitary Gland Flashcards
Which endocrine glands are found in the cranial cavity?
Hypothalamus
Pituitary gland
Which endocrine glands are found in the neck?
4 parathyroid glands
Thyroid gland
Which endocrine glands are found in the abdomen?
2 adrenal glands
Pancreas
Which endocrine glands are found in the pelvis/perineum?
Female = 2 ovaries in broad ligaments Male = 2 testes in scrotum
What is the diencephalon?
Central core of cerebrum
Communication between cerebral hemispheres and midbrain
Thalamus + hypothalamus
What are the three parts of the brain stem?
Midbrain
Pons
Medulla oblongata
What connects the hypothalamus and pituitary gland?
Infundibulum
Where is the pituitary gland located?
Midline structure in the pituitary fossa of the sphenoid bone
Where does the pituitary fossa lie?
Within the sella turcica
Where does the pituitary glad lie in relation to the visual pathway?
Immediately inferior to the optic chiasma
What forms the optic chiasma?
The right end left optic nerves
What is the visual pathway for eight rays from the nasal side of the visual field?
Nasal side of visual field Temporal retina Lateral side of optic canal Optic chiasma Same side (i.e. left on left, right on right) optic tract Synapse in thalamus Optic radiation Visual cortex in occipital lobe
What is the visual pathway for light rays from the temporal side of the visual field?
Temporal side of visual field Nasal retina Medial side of optic canal Optic chiasma Cross to opposite side (i.e. right to left, left to right) optic tract Synapse in thalamus Optic radiation Visual cortex in occipital lobe
What effect can a pituitary tumour have on the visual pathway?
Bitemporal hemianopia
Disrupts APs from nasal retina bilaterally (since these are the ones which cross at optic chiasma, which may be compressed with a tumour)
What are the two routes of surgical approach to the pituitary fossa?
Transcranial approach = Under the frontal lobe
Transsphenoidal approach = via nasal cavities ad sphenoid sinus
What are the paranasal sinuses and where are they located?
Fronta sinuses = frontal bone
Maxillary sinuses = Maxillae
Ethmoidal air cells = Ethmoid bone
Sphenoid sinuses = Sphenoid bone
What lines the paranasal sinuses?
Mucous secreting respiratory mucosa
What is the function of the paranasal sinuses?
Make mucous and drain it into the nasal cavities via ostia
Reduce weight of skull
Add resonance to voice
What surgical fractures are required for the transsphenoidal transnasal approach?
Nasal septum
Floor and roof of sphenoid sinus
What is the dura mater?
Meningeal area that surrounds the brain
Adherent to the internal aspects of all the bones of the cranial vault
What is the tentorium cerebelli?
Tough sheet of dura mater tenting over the cerebellum within the posterior cranial fossa
Why is there a central gap in the tentorium cerebelli?
To allow the brainstem to pass through
What is the diaphragm sellae?
Tough sheet of dura mater forming a roof over the pituitary fossa
What are the dural venous sinuses?
Venous channels within the dura mater that drain most of the venous blood from the cranial cavity into the IJVs
Where do the dural venous sinuses drain?
Into the internal jugular veins at the jugular foraminae in the floor of the posterior cranial cavity
What structures surround the pituitary gland?
Cavernous and inter cavernous sinuses
What structures are at risk in pituitary gland surgery?
Optic chiasma Oculomotor nerve Trochlear nerve Trigeminal nerve Abducent nerve Cavernous sinus Internal carotid artery Dura mater
