Pituitary Gross Anatomy
What bony structure houses the pituitary gland?
Sella turcica of the sphenoid bone.
The sella turcica is a depression in the sphenoid bone. The sphenoid sinus lies inferiorly, allowing a transsphenoidal surgical approach to the pituitary.
What are the pink, homogeneous structures filling the thyroid follicles?
Colloid
Colloid contains thyroglobulin, which serves as the extracellular storage form of thyroid hormone precursor. This is a distinctive feature of thyroid histology.
Which embryonic structure gives rise to the anterior pituitary?
Rathke's Pouch
Which pituitary lobe contains densely packed hormone-secreting epithelial cells?
Anterior Pituitary
A pituitary macroadenoma compresses the optic chiasm. What classic visual field defect results?
What structure connects the hypothalamus to the pituitary gland?
Infundibulum / Pituitary Stalk
The infundibulum connects the hypothalamus and pituitary. It contains hypothalamic axons extending toward the posterior pituitary and portal vessels supplying the anterior pituitary.
Which follicle is more active: one lined by flattened cells or one lined by taller columnar cells?
Columnar
From which germ layer does Rathke pouch originate?
Oral ectoderm
The anterior pituitary is derived from oral ectoderm, which explains its glandular epithelial organization rather than neural tissue organization.
Which staining category of anterior pituitary cells produces GH and prolactin?
Acidophils
A surgeon approaches a pituitary tumor through the nasal cavity. Which sinus must be traversed to reach the sella turcica?
Sphenoid sinus
Which structure lies directly superior to the pituitary gland and is vulnerable to compression by a macroadenoma?
Which small, polygonal cells arranged in cords and nests produce PTH?
Chief / Principle Cells
Chief cells are small polygonal cells arranged in cords and nests, closely associated with fenestrated capillaries that allow PTH to enter the circulation
The posterior pituitary develops as a downward extension of which embryonic structure?
Diencephalon
Which staining category includes cells that produce ACTH, TSH, FSH, and LH?
Basophils
FLAT base!
A patient develops hoarseness after thyroidectomy. Injury to which nerve is a major concern?
Recurrent laryngeal n
The recurrent laryngeal nerve typically ascends near the tracheoesophageal groove and has a variable relationship to branches of the inferior thyroid artery. Injury may cause vocal fold weakness and hoarseness.
A pituitary tumor expands laterally. Which venous sinus containing CN III, IV, V1, V2, and VI may be affected?
Cavernous Sinus
The cavernous sinus contains CN III, IV, V1, V2, and VI, as well as the internal carotid artery. CN VI runs within the sinus alongside the ICA, making it particularly vulnerable to cavernous sinus pathology.
Which region contains unmyelinated axons, pituicytes, and numerous capillaries?
Pars nervosa
Remnants of Rathke pouch may persist as colloid-filled cysts in which pituitary region?
Pars intermediata
The pars intermedia lies between the pars distalis and pars nervosa. Remnants of Rathke pouch may appear as colloid-filled cysts in this region.
Which glial-like cells are characteristic of the posterior pituitary?
Pituicytes
ADH and oxytocin are synthesized in hypothalamic neurons, not by pituicytes.
Following thyroidectomy, a patient has difficulty producing high-pitched sounds. Which nerve was most likely injured?
External branch of superior laryngeal n -- supplies the cricothyroid muscle
Which artery supplies the primary capillary plexus that drains into the hypophyseal portal veins?
Superior hypophyseal artery
The superior hypophyseal artery supplies the primary capillary plexus near the median eminence. Blood travels through the hypophyseal portal veins to the anterior pituitary, allowing hypothalamic regulatory hormones to reach their targets.
Which parathyroid cells have abundant eosinophilic cytoplasm, are rich in mitochondria, and increase in number with age?
Oxyphil cells
Oxyphil cells are larger than chief cells, with abundant eosinophilic cytoplasm due to their high mitochondrial content. Their numbers increase with age and are associated with high amounts of adipose.
A suprasellar tumor arises from remnants associated with Rathke pouch development. What tumor is classically associated with this origin?
Craniopharyngioma
What are the dilated accumulations of neurosecretory material found along axons in the pars nervosa called?
Herring Bodies
Herring bodies are accumulations of neurosecretory material within axons of the posterior pituitary, containing stored ADH or oxytocin before release into nearby capillaries.
During thyroid surgery, a surgeon identifies a parathyroid gland unusually low in the neck, near the thymus. Which embryologic origin explains this location?
3rd laryngeal pouch