Pituitary gland: Difference between revisions
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Pituitary gland is located within the sella turcica of the sphenoid bone. | |||
= Anterior and posterior pituitary lobe = | |||
<table class="wikitable" width="100%"> | |||
<tr> | |||
<th width="50%">Adenohypophysis</th> | |||
<th width="50%">Neurohypophysis</th> | |||
</tr> | |||
<td> | |||
75% of the gland<br> | |||
Ectodermal origin from roof of the stomodeum<br> | |||
Three components: | |||
# Pars tuberalis includes <br> Portion of the infundibular stalk <br>Median eminence of hypothalamus | |||
# Pars intermedia | |||
# Pars distalis: majority of the gland, has no direct arterial supply | |||
</td> | |||
<td> | |||
25% of the gland<br> | |||
Diencephalic origin<br> | |||
Three components: | |||
# Pars nervosa (posterior lobe) | |||
# Infundibulum | |||
# Nuclei (supraoptic and paraventricular) | |||
</td> | |||
</table> | |||
= Hypophyseal portal system = | |||
* Hypophyseal portal system is formed by the superior hypophyseal arteries (supraclinoid ICA) and the inferior hypophyseal arteries (branch of cavernous ICA meningohypophyseal trunk). | |||
* These arteries join in and around the pituitary stalk and form sinusoids that feed the infundibulum and the anterior pituitary gland. | |||
* The superior hypophyseal artery supplies the infundibulum and the median eminence. | |||
* The inferior hypophyseal artery supplies the posterior pituitary lobe. | |||
<br> | |||
<center><sketchfabplaylist>b59aae3f7ba547bd9eccb69ea1587fb0</sketchfabplaylist></center> | |||
== Superior hypophyseal artery == | |||
* several small arteries arising from the posteromedial portion of the intradural ICA | |||
* They course beneath the optic nerve to supply: | |||
** Pituitary (anterior pituitary lobe, pituitary stalk) and tuber cinereum | |||
** Optic nerve and chiasm (inferior surface) | |||
== Inferior hypophyseal a. == | |||
* ⇒ posterior lobe of pituitary | |||
* postpartum occlusion causes pituitary infarcts (Sheehan's necrosis): however, DI is rare because the stalk is spared | |||
[[Category:Neuroanatomy]] | [[Category:Neuroanatomy]] | ||
Latest revision as of 01:05, 5 March 2024
Pituitary gland is located within the sella turcica of the sphenoid bone.
Anterior and posterior pituitary lobe
| Adenohypophysis | Neurohypophysis |
|---|---|
|
75% of the gland
|
25% of the gland
|
Hypophyseal portal system
- Hypophyseal portal system is formed by the superior hypophyseal arteries (supraclinoid ICA) and the inferior hypophyseal arteries (branch of cavernous ICA meningohypophyseal trunk).
- These arteries join in and around the pituitary stalk and form sinusoids that feed the infundibulum and the anterior pituitary gland.
- The superior hypophyseal artery supplies the infundibulum and the median eminence.
- The inferior hypophyseal artery supplies the posterior pituitary lobe.
Superior hypophyseal artery
- several small arteries arising from the posteromedial portion of the intradural ICA
- They course beneath the optic nerve to supply:
- Pituitary (anterior pituitary lobe, pituitary stalk) and tuber cinereum
- Optic nerve and chiasm (inferior surface)
Inferior hypophyseal a.
- ⇒ posterior lobe of pituitary
- postpartum occlusion causes pituitary infarcts (Sheehan's necrosis): however, DI is rare because the stalk is spared