Tuesday - Thyroid, pineal Histo - Aubie Flashcards
In which ventricle is the pineal gland located?
Third
it’s lobulated, has a pia matter capsule and lots of capillaries
2 cell types of pineal gland and what they do
Pinealocytes - melatonin production
Glial cells - support (can’t really see them)
“brain sand” accumulates with age. What’s it made of?
Pineal gland isn’t midline, what might you have?
Calcium and Phosphate
cerebral tumor
What is the nerve supply to pineal gland?
What do they release?
sympathetics from superior cervical ganglion
epinepherine
What does melatonin do?
Suppresses gonadotropin secretion (FSH, LH)
Slows gonadal growth (no pineal funtion –> early puberty)
Emotional response - Seasonal Affective Disorder (too much melatonin)
What type of epithelium lines the follicles of the thyroid?
any simple epithelium (sqam, cube, column)
What does colloid contain?
Thyroglobulin, a precursor to thyroid hormones
2 cell type of the thyroid
Follicular cells Parafollicular Cells (c-cells)
What do follicular cells do?
make thyroid hormone!
microvilli on apical side go into colloid
Follicular cell has rough ER at base and is squamous or cuboidal, small amount of golgi, what’s it doing?
It’s inactive or resting. So, producing basal levels of thyroglobulin.
Properties of an Active follicular cell:
Columnar lots of mitochondria, ER and golgi PAS positive Lysosomes Release T3 and T4
Parafollicular cells:
Made from?
What do they Make?
Pharyngeal ectoderm newest info from Aubie
(neural crest in First Aid)
make calcitonin
What does calcitonin do?
inhibits bone resorption –> lower Calcium
decrease osteoclast
increases excretion on Ca and Phosphate from kidney
What amino acid is prevalent in thyroglobulin?
Tyrosine
able to be iodinized
How does Iodine get into colloid?
basal part of follicular cells cotransport iodiDe with sodium in to cell
puts iodide into colloid
IodiDe–>IodiNe via oxidation in colloid (extracellularly)
What increases T3 and T4 production?
where is that made?
TSH - from the basophils in pars distalis
How is the thyroglobulin from the colloid put into blood?
Pinocytosis –> fuse with lysosome –> proetolysis –> active T3 and T4 –> released into capillaries –> bind to carrier proteins
Parathyroid
Where is it
What’s it made from
posterior surface of thyroid (separated by capusule)
made from from pharyngeal endoderm
3rd brancheal pouch –> inferior
4th bracheal pouch –> superior
3 types of cells in parathyroid:
Chief
Oxyphil
Fat
What cell make PTH?
What does it look like?
Chief cell
Big, dark nucleus
small eosinophilic plasma
can be resting or active
How does PTH work?
Simulates osteoblasts to make RANKL –> stimulates osteoclasts –> bone resorption
What do oxyphil cells look like?
What do they do?
They’re bigger than Chief, stain lighter (pink)
nuclei are smaller and darker
lots of mitochoniria
don’t know what they do, darn.
