Endocrine Flashcards
Where is the pituitary gland located?
Sells turcica of sphenoid bone, about 1cm below optic chiasm
What is the visual defect caused by enlargement of the pituitary?
Bitemporal hemianopia
How are the pituitary and hypothalamus connected?
Via the infandibulum (pituitary stalk)
Describe the pituitary gland
Splits into anterior and posterior lobes
The anterior is the larger of the two, making up 2/3 of the gland, the posterior 1/3
Anterior pituitary is glandular and manufactures hormones
Describe the histology of the pituitary gland
With H&E stain the anterior pituitary stains dark, while the posterior stains light
The anterior has 3 cell types
- acidophilic (again pink)
- basophilic (again purple)
- chromophobic (hardly stain, appear clear/pale)
What are the secretions of the different types of chromophils?
Acidophilic
- somatotropin
- Prolactin
Basophilic
- ACTH
- TSH
- FSH
- LH
What are the secretory cells in the posterior pituitary?
Non-myelinated axons
Neurosecretory cells
Describe blood supply to the pituitary
Branches of the ICA
- superior hypophyseal artery supplies AP
- inferior hypophyseal artery supplies PP
Describe venous drainage of the pituitary
Through hypophyseal veins to the cavernous sinus
Where is the thyroid gland located?
Vertebral level C5-T1 between thyroid cartilage and 6th tracheal ring
Isthmus lies between 2nd-4th tracheal rings
What strap muscles overly the thyroid?
Omohyoid
Sternohyoid
Sternothyroid
What nerves supply the vocal cords?
Recurrent laryngeal (loops around sorta) and superior laryngeal nerve
Superior laryngeal splits into external and internal branches
Describe blood supply to the thyroid gland
ECAs give off superior thyroid arteries
Subclavian arteries give off inferior thyroid arteries
Describe venous drainage of the thyroid gland
Superior and middle thyroid veins drain into IJV
Inferior thyroid veins drain into brachiocephalic
Describe thyroid gland histology
Cavities surrounded by follicular (secretory) cells
Cavities contain colloid = thyroid hormones bound to thyroglobulin
What hormones are secreted by the thyroid gland?
Thyroid hormones (T3 and T4) and calcitonin
Where are the parathyroid glands situated?
Medial half of posterior surface of each thyroid lobe
Most people have four
Superior are at level of inferior border of cricothyroid, inferior position varies
They are separated from thyroid gland by thing fibroid capsule
Parathyroid histology
Differentiated from thyroid gland by think capsule
At high power may see two cell types
- chief cells (more numerous and darker staining)
- oxyphil cells
Describe the suprarenal glands
Retroperitoneal endocrine glands located superior to kidney
Each has 2 parts: cortex and medulla
Embryologically what did the two parts of the suprarenal glands derive from?
Cortex: mesodermal epithelium
Medulla: neuroectoderm
Describe blood supply to the suprarenal glands
Suprarenal arteries arise from the inferior phrenic and renal arteries as well as the aorta
Describe suprarenal venous drainage
Right suprarenal vein drains directly to IVC
Left suprarenal vein drains in to left renal vein
Describe the adrenal cortex
3 layers
Zona glomerulosa: secretes mineralocorticoids
Zona fasciculata: secretes glucocorticoids
Zona reticularis: secretes androgens
Describe adrenal medulla connections for secretion
Connected to ovoid chromaffin cells which secrete Adrenalin and noradrenalin
