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
What is the parenchyma of the adrenal gland devided into? What does each part produce ( borad term)
Cortex: Steroid secreting portion
Medulla: Catecholamine secreting portion
What is the name of the medulary cells? What type of cells are they? What do they secrete?
cromaffin cells
modified neurons,
receive signals from the sympathetic
system to release catecholamines.
What is used to stain chromaffin cells
Chromium salts
How does chromatin staning indicate what it secretes?
Cells with dense core vesicles secrete norepinephrine
•Cells with smaller, less dense vesicles secrete epinephrine
List the three zones in the adrenal gland and the percentage of the cortical volume it
- Zona glomerulosa: Narrow outer zone up to 15% of the cortical volume.
- Zona fasciculata: Thick middle zone about 80% of the cortical volume.
- Zona reticularis: The inner zone only 5% of the cortical volume.
Describe the structure of the cells, how they are arranged, the nuclei and matrix of the zona glomerulosa. What do the cells secrete? And what stimulates the secretion of this hormone?
Small, columnar or pyramidal cells with spherical and densely stained nuclei.
•Arranged in ovoid clusters, and arch-like cords, seperated by fibrous trabeculae
•Small lipid droplets, extensive RER.
•Synthesize and secrete mostly aldosterone (stimulated by angiotensin II and ACTH).
What is this histological image showing? Describe the image
Zona glomerulosa
cells- columnar or pyramidal seperated by fibrous trabeculae
Arranged in- avoid clusters
Nuceli- spherical shape and densily stained
Describe the structure of the cells, how they are arranged, the nuclei and matrix of the zona Fasciculata.
What do the cells secrete? And what stimulates the secretion of this hormone?
Cells- Large, polyhedral cells, in straight chords. separated by sinusoidal capillaries.
Nuceli- separated by sinusoidal capillaries.
Matrix- Acidophillic cytoplasm with numerous lipid
droplets,
Secretion? Secrete glucocorticoids that regulate
glucose and fatty acid metabolism
(cortisol), secretion is regulatedby
Adrenocorticotropic hormone (ACTH).
What does this histological image show? Describe it?
cells- plyheadral cells, arranged in staright cords, seperated by sinusoidal capillaries
- Nuclei- lightly stained, sepherical (sometimes bi-nucleated)
Secretes: glucocorticoids (corsiol) stimulated adrenocorticotrophic hormone
Describe the structure of the cells, how they are arranged, the nuclei and matrix of the zona Reticularis.
What do the cells secrete? And what stimulates the secretion of this hormone?
•Small cells, densely stained nuclei, in chords,
separated by fenestrated capillaries.
•Light and dark cells, dark cells contain
lipofuscin granules (lysosomal digestion).
•Cells have less cytoplasm than ZF, more
closely packed.
•Synthesis and secretion of weak androgens.
Also some glucocorticoids (cortisol).
•Secretion also regulated by ACTH.
what lies under the zona reticularis?
The medulla
What does the medulla secrete?
Catecholamines- epinephrin and norepinephrin
What are chromaffin cell tumours called?
Phaeochromocytoma
What is Cushing’s Syndrome?
Hypercortisolism
What are the histological changes which occure during cushings syndrome?
Cortical atrophy: (ZF and ZR lack stimulation, while ZG appears normal being
ACTH independent) — exogenous glycocorticoids
• Diffuse hyperplasia: ACTH dependent, cortex is diffusely thickened with lipid-rich
cells (vacuolated)
What is addisons diease?
Hypocorticolism
What are the histological changes which occure during Addisons disease?
Atrophic glands
• Fibrosis of adrenal capsule
• No differentiation of the cortical epithelial areas and the medulla
• Marked lymphocytic infiltration (autoimmune)
Where is the pituitary gland located?
Sella turcica in the sphenoid bone
What connects the pituitary gland to the hypothalamus?
The pituitary stalk- the infundibulum
What is another name for the anterior and posterior pituitary gland? What type of cell will you find in each?
Anterior- adenophyphesis (glandular epethelial)
Poesterior- neurophypophesis (neural secretory cells)
What seperates the cells in the anterior pituiatry?
Describe the organisation of the cells
fenestrated capillaries
cells in clumps and chords
List the 3 cell types found in the anterior pituitary and state there adunance in percentages
Basophils (10%)
Acidophils (40%)
Chromophobes (50%)
Which cells fall under basophils cells? What do they produce?
Gonadotropes- Produce luteinizing hormone
(LH) and follicle stimulating hormone (FSH)
Thyrotropes- Produce TSH
Corticotropes- Produce adenocorticotropic
hormone (ACTH), and beta lipoprotein.
Which cells fall under acidophils cells? What do they produce?
Somatotropes
Synthesize growth hormone (GH)
Which cells fall under chromophobes? what do they produce?
Lactotropes which produce prolactin. Chromophobes when content is being released otherwise acidophils
Why is the posterior lobe not an endocrine gland?
Because it is an extension of the CNS and
stores and releases secretory products from the
hypothalamus
What is the name of the glial cells found in the hypothalamus?
Pituicytes
What is the hypothalamic hypophysial
tract.
Unmyelinated axons derived from neuroendocrine
cells, whose bodies lie in the hypothalamus
(hypothalamic supraoptic and paraventricular
nuclei) and release neurosecretions in the posterior pituitary gland
What are Herring bodies? What do they contain and where do they terminate?
intermittent bulging segments of
axons in the hypothalamic hypophysial
tract.
- contain neuroendocrine secretory granules.
- terminate very close to the fenestrated capillaries.
Where are secretory grandules located in the posterior pituitary? What do these secretory granules contain?
located in the herring bodies
Conatin carriere proteins called neurophesis which contain ADH and oxytocin
List the cell types found in the posterior pituiray?
Fibroblast, Mast cells, pituicytes
What is contained in the pituicytes?
Glial fibrillary acidic protein
Name 3 histological features of a pituitary ademoma
Into where does the pancrease secrete its enzymes?
Duodenum
In the pancreas what is responsible for the synthesis and secretion of insulin and glucagon?
islets of Langerhans
What are acinar cells?
Cells which synthesisze and secrete digestive enzymes in the pancrease
Name the different types of cells in the islet of Langerhans? What they secrete and what colour they will be in Immunofluorescence
imaging?
A (alpha)- Red produce glucagon.
B (beta)- Brownish Orange produce insulin.
D (delta)- Blue produce somatostatin.
Name 3 pathological manifestations in the pancreas and a condition they may relate to
Reduction in the number and size of islets: DT1
Leukocytic infiltrates in the islets (insulitis): principally of T lymphocytes
Amyloid deposition within islets - fibrosis in advanced stages: DT2
