Tuesday - Thyroid, pineal Histo - Aubie

Question 1

In which ventricle is the pineal gland located?

Answer 1

Third

it’s lobulated, has a pia matter capsule and lots of capillaries

Question 2

2 cell types of pineal gland and what they do

Answer 2

Pinealocytes - melatonin production

Glial cells - support (can’t really see them)

Question 3

“brain sand” accumulates with age. What’s it made of?

Pineal gland isn’t midline, what might you have?

Answer 3

Calcium and Phosphate

cerebral tumor

Question 4

What is the nerve supply to pineal gland?

What do they release?

Answer 4

sympathetics from superior cervical ganglion

epinepherine

Question 5

What does melatonin do?

Answer 5

Suppresses gonadotropin secretion (FSH, LH)

Slows gonadal growth (no pineal funtion –> early puberty)

Emotional response - Seasonal Affective Disorder (too much melatonin)

Question 6

What type of epithelium lines the follicles of the thyroid?

Answer 6

any simple epithelium (sqam, cube, column)

Question 7

What does colloid contain?

Answer 7

Thyroglobulin, a precursor to thyroid hormones

Question 8

2 cell type of the thyroid

Answer 8

Follicular cells
Parafollicular Cells (c-cells)

Question 9

What do follicular cells do?

Answer 9

make thyroid hormone!

microvilli on apical side go into colloid

Question 10

Follicular cell has rough ER at base and is squamous or cuboidal, small amount of golgi, what’s it doing?

Answer 10

It’s inactive or resting. So, producing basal levels of thyroglobulin.

Question 11

Properties of an Active follicular cell:

Answer 11

Columnar
lots of mitochondria, ER and golgi
PAS positive
Lysosomes
Release T3 and T4

Question 12

Parafollicular cells:
Made from?
What do they Make?

Answer 12

Pharyngeal ectoderm newest info from Aubie
(neural crest in First Aid)

make calcitonin

Question 13

What does calcitonin do?

Answer 13

inhibits bone resorption –> lower Calcium

decrease osteoclast

increases excretion on Ca and Phosphate from kidney

Question 14

What amino acid is prevalent in thyroglobulin?

Answer 14

Tyrosine

able to be iodinized

Question 15

How does Iodine get into colloid?

Answer 15

basal part of follicular cells cotransport iodiDe with sodium in to cell

puts iodide into colloid

IodiDe–>IodiNe via oxidation in colloid (extracellularly)

Question 16

What increases T3 and T4 production?

where is that made?

Answer 16

TSH - from the basophils in pars distalis

Question 17

How is the thyroglobulin from the colloid put into blood?

Answer 17

Pinocytosis –> fuse with lysosome –> proetolysis –> active T3 and T4 –> released into capillaries –> bind to carrier proteins

Question 18

Parathyroid
Where is it
What’s it made from

Answer 18

posterior surface of thyroid (separated by capusule)

made from from pharyngeal endoderm
3rd brancheal pouch –> inferior
4th bracheal pouch –> superior

Question 19

3 types of cells in parathyroid:

Answer 19

Chief
Oxyphil
Fat

Question 20

What cell make PTH?

What does it look like?

Answer 20

Chief cell
Big, dark nucleus
small eosinophilic plasma
can be resting or active

Question 21

How does PTH work?

Answer 21

Simulates osteoblasts to make RANKL –> stimulates osteoclasts –> bone resorption

Question 22

What do oxyphil cells look like?

What do they do?

Answer 22

They’re bigger than Chief, stain lighter (pink)
nuclei are smaller and darker
lots of mitochoniria

don’t know what they do, darn.