Pituitary Gland Anatomy Flashcards
what makes up the diencephalon?
thalamus and hypothalamus
what does the diencephalon form?
central core of cerebrum with connections to right and left cerebral hemispheres and midbrain
what is the infundibulum?
anatomically and functionally connects the hypothalamus and the pituitary gland
what can the infundibulum otherwise be known as?
pituitary stalk, infundibulum=funnel
what lobes is the pituitary anatomically and functionally divided up into?
anterior and posterior
what is the anterior lobe also known as?
adenohypophysis
- pars distalis
- pars tuberalis
- pars intermedia
what is the posterior lobe also known as?
neurohypophysis
-pars nervosa
which lobe is an extension of brain?
posterior
which lobe synthesises and releases most of the pituitary hormones?
anterior
which hormones does the posterior lobe produce?
ADH and oxytocin (synthesised in hypothalamus)
what is the location of the pituitary gland?
it is a midline structure in the pituitary fossa of the sphenoid bone (deep in cranial cavity)
where does the pituitary fossa lie?
sella turcica
what is the relation between the pituitary gland and the optic chiasm?
lies immediately inferior to the optic chiasm
what is the brain stem continuous with?
spinal cord
what is the controlling centre for the whole endocrine system?
hypothalamus
what is the thalamus?
centre for sensation
what does sella turcica mean?
turkish saddle
what are the visual fields?
nasal and temporal (right and left)
what are the photoreceptors in the nasal and temporal retina?
rods and cones
what is the optic chiasma formed from?
right and left optic nerves
what visual fields cross over?
nasal
what clinical feature can a pituitary tumour result in?
bitemporal hemianopia
why does bitemporal hemianopia occur?
tumour impinging on optic chiasma which disrupts transmission of action potentials from nasal retina bilaterally
what field of vision is restricted in bitemporal hemianopia?
temporal (medial part of retinas)
what are the two surgical access areas?
transcranial and transsphenoidal
what surgical access type is more common?
transsphenoidal
what are nasal conchae covered by?
mucous membranes
what do nasal conchae do?
warm air and help to humidify it when breathing through the nose
what are paranasal sinuses?
air filled spaces within bones surrounding nasal cavities
what are paranasal sinuses lined by?
mucus-secreting respiratory mucosa
is there a known function of paranasal sinuses?
no
what are some suggested functions of paranasal sinuses?
secrete mucus which drains into nasal cavities through ostia (single=ostium-bony drainage hole), reduce weight of the skull, add resonance to voice
what are Le Fort fractures of the facial skeleton?
nasty fractures that depend on how much of the eye or orbital cavity is involved
what is significant about Le Fort 1 fractures?
Le Fort 1 down fracture approach to the nasal cavities provides better surgical access in more complicated cases
what is dura mater?
thick fibrous membrane that covers the whole brain and lines the entire cranial cavity internally
what do the vertebral arteries anastomose to form?
basilar artery
what is the tentorium cerebelli?
thought sheet of dura mater tenting over cerebellum in posterior cranial fossa but has a central gap to allow brainstem to pass through
what is the diaphragm sellae?
tough sheet of dura mater forming roof over pituitary fossa and sellae turcica
what does trigeminal mean?
three twins
what are dural venous sinuses?
venous channels within dura mater that drain most of venous blood from cranial cavity including the brain into internal jugular veins (spaces between dural folds
what makes dural venous sinuses different to veins?
no proper venous walls (different histologically but similar function
where do dural venous sinuses drain into internal jugular veins?
jugular foraminae in the floor of posterior cranial fossa
