Endocrine Histology Flashcards
Fill out the lebels on this diagram
What is the name of the functional unit of the thyroid gland
Thyroid Follicles
What is the red arrow pointing to? Describe this structure
What is the black arrow pointing to? What does it produce?
What is the red star indicating? What does it produce?
Red arrow- Thyroid follicle surrounded by. A single layer of Follicular epithelium. Cuboidal/ squamous (less active) or culomnar (active)
Parafollicular or C cells. They produce calcitonon
Red star- Colloid contains iodinated thyroglobulin (T3 and T4)
What seperates each follicular cell? What can be found enclosed in this structure?
Connective tissue called septa (collagenous)
A rich blood supply, lymphatics and nerves
What is the apical and basal surface of the follicular epethilial cell attached to?
Apical- Colloid
Basal- Basement membrane
Describe where parafollicular cells are located
Sandwitched between follicular cells, no exposure to follicular lumen
What is the function of calcitonin? How is its production regulated?
- Physiologic antagonist of the parathyroid hormone (PTH).
– Regulates calcium levels by suppressing the action of osteoclasts.
– Secretion is regulated by serum calcium levels.
What do the labels on this image stand for?
F: follicle
CT: connective tissue
BV: blood vessels
tsF: top section of
follicle
List the 3 hormones produced by the thyroid gland and where each is produced
Thyroxine (T4), triiodothyronine (T3)- Colloid of follicular cells
Calcetonin- Parafollicular cells
What is the function of Thyroxine (T4) and triiodothyronine (T3)? What regulates them?
Regulate body growth, metabolism and development
Production is regulated by TSH produced by the anterior pituitary gland
What is hyperthyroidism? List 2 specific conditions which fall under this umbrella
hypermetabolic state caused by elevated circulating levels of
free T3 and T4
Conditions: Graves diease and Thyrotoxicosis
What is hypothyroidism? List 2 specific conditions which fall under this umbrella
structural or functional abnormalities that interfere with
thyroid hormone production
Hashimoto Thyroiditis, autoimmune thyroid
disease
What is the cellular manifestation of graves diease?
-Diffuse hypertrophy and hyperplasia (enlarged organ) of follicular cells (tall and columnar and
more crowded)
This causes papillary formation which extend into the lumen
-Lymphoids (mianly T cells) infiltrate thyroid stroma
-Cytoplasmic eosinophilia, with enlarged
nuclei
What is the meaning of the term cytoplasmic eosinophilia?
When more cells take up the stain Eosin, the histology looks more pink. The type of cells which take uo this stains are proteins such as collagen. This indicates there are more proteins potentially conncetive tissue in the histology
Describe the histology of hashimito thyroiditis
- Wide speard inflitration of mononuclear inflammatory cells. These consist of lymphocytes, plasma cells and well developed germinal centers (clusters of differentiating B cells)
- Follicles are atrophic, distinguished by abundant eosinophilic epithelial cells
(Hürthle cells)
-Interstitial connective tissue is increased
Which diease will cause this kind of histology? Explain what is happening here
Graves diease
The epithelial cells in this patient no longer surround round follicles of colloid. Instead, these follicles are disappearing and the colloid is becoming depleted.
What is the arrow indicating and why is it happening?
The colloid is being depleted, it is no longer round but is forming jaggerd scaloped edges. This is happening because the thyroid hormone in the colloid is being turned over faster. More T3 and T4 is being produced
What is the red circle indicating? Why is this happening?
Circle indicates papillae
This is the over growth and multiplication of the follicular epethilum. It grows so much it beings to bulge into the center where the colloid is located
What does the blue arrow indicate
What do the red circles indicate?
Blue arrow- lymphocytes and germinal centers
Red circle- Hurthle cells- epethilium of thyroid follicles is big and pink
How does the parathyroid gland change with age and how does this occur?
It gets larger with age
Due to increase in fat cells and oxyphil cells
The normal parenchyma of the thyroid gland is composed of two cells, what are there names?
Chief cells and oxyphil cells
What is the function of chief cells?
They regulate the synthesis, storage and secretion
of large amounts of PTH which raises blood calcium
levels
replicate when stimulated by changes in
blood calcium (transmembrane Ca2+ receptor
on cell membrane, that binds calcium ions).
Write a small description of chief cells
small with pale-stained cytoplasm, with
vesicles containing lipofuscin, glycogen and
lipids.
Write a small description of oxyphil ells
Round, larger than cheif cells, Esinophilic, unknown function
In the image what does P, O and C indicate?
P- cheif cells
0- oxyphil cells
C- capillaries