Histology-Thyroid, Parathyroid, Adrenal Flashcards
What are the structures indicated below?
1) Compact bone 2) Bone marrow
What are the structures indicated below?
1) Bone spicule 2) Osteocytes 3) Osteoclast 4) Osteoblast (forming endosteum)
What are the structures indicated below?
1) Esophagus 2) Trachea 3) Thyroid gland
What are all the white spots in this section of the thyroid?
Blood vessels, lots of them bc its endocrine
What are these cells secreting and storing?
Thyroid follicular cells are secreting thyroglobulin. It gets iodinated and stored in colloid until it gets released. Note the reabsorption lacunae where the colloid is being broken down to thyroid hormone
What do these cells secrete?
Parathyroid cells secrete calcitonin
What type of capillaries are these?
The thyroid gland has fenestrated (with diaphragms) capillaries
What gland is this?
Parathyroid. Note the lobulation, many blood vessels (shown below) and adipocytes
What cells are in the parathyroid gland?
Chief cells (secrete PTH), adipocytes and oxyphils
What embryonic origins do the areas indicated below come from?
Mesenchymal cells = 1) adrenal cortex. Neural crest cells = 2) adrenal medulla.
Starting from the outside in, what are the layers of the adrenal gland?
Capsule -> Cortex -> Medulla
How did we get this stain?
A chromaffin stain stains the cells that are only secreting NE and EPI
What are the three layers of the cortex?
1) Zona glomerulosa (mineralocorticoids) 2) Zona fasciculata ( 3) Zona reticularis (linear cords)
Why are cells in the zona fasciculata “foamy”?
They are full of fatty ester droplets to use a substrate for steroid synthesis
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Zona reticularis. Note that the cells in the medulla (#3) are larger than those in the zona reticular is.
How does blood flow through the adrenal gland
Capsule arterioles -> Plexus feeds cortex ->
Why does blood flow the direction it does in the adrenal gland?
You need the influence of the glucocorticoids from the cortex to synthesize the enzyme (PNMT) to allow conversion of NE to EPI in the adrenal medulla.
How do NE and EPI get into the blood from the adrenal gland?
NE and EPI are not lipid soluble and cannot diffuse across a cell membrane, but can diffuse through fenestrae in the capillary pores.
