Endo Histo Flashcards
zones of the cortex?
outside - inside
zona glomerulosa
zona fasiculata
zona reticulatis
The cortex does not have its own venous supply so hormones from the cortex will drain through the medulla to arrive at that central vein. They can and do influence the medulla.
pituitray acinus
This round arrangement of anterior pituitary cells is an acinus.
Normal adenohypophysis is composed of small acini of pituitary cells surrounded by an intact reticulin network (a). In hyperplasia, the acinar architecture is maintained and the reticulin network is preserved, but the acini are increased in size ( b). In contrast, pituitary adenomas are characterized by complete disruption of the reticulin fiber network ( c). Immunohistochemical stains are required to determine the hyperplastic cell population, and these stains will identify the admixed normal cells that contain all of the normal adenohypophysial hormones.
parathyroid
There is more fat in the parathyroid with increasing age.
delta cells
secrete somatostatin
inhibit glucagon and insulin
few
pars distalis vs pars nervosa - how to tell the difference
pars distalis is much more cellular than the pars nervosa
cromaffin cells - direct input from sympatehtic neurons
adrenal medulla
cortical hormones inhibit axonal growth in vivo
This is called a chromaffin stain. The cells have an affinity for dichromate and that’s why they stain this way. This identifies them as a neural crest derivative and they have a unique feature which is that they actually are like post-synaptic neurons. Sympathetic nervous system cells actually synapse directly with cells in the medulla. Whereas cells in the cortex are again producing precursors which will be released when the cortex is stimulated by ACTH. The medulla stores the active hormone and the hormones released by the medulla are epinephrine and norephinephrine—the fight or flight response. These can be released immediately and I’m sure you have felt their effects, postive or negative. You will feel your heartbeat/RR immediately increase. Will shut down blood vessels to your gut, dilate blood vessels to skeletal muscles and brain. Secreted directly into the bloodstream rather than having to first be converted to become active.
psomma body
papillary carcinoma
Psammoma body: calcified structures (tumor cell necrosis)
parathyroid
adipocyte
insulinoma
neuroendocrine tumor
beta cell origin
circumscribed by a fibrous capsule
excess insulin causes hypoglycemia
90% benign
beta cells
secrete insulin stimulating glucose uptake by muscle and fat cells and fat storage
delta cells
least
secrete somatostatin
cd8
CD4, B, Plasma cells but the thing you have the most is cytotoxic CD8 t cells!
D
medulla
thyroid
thyroid adenoma
The thyroid adenoma follicles directly resemble the normal thyroid gland epithelium. It is a clonal proliferation of cells that is surrounded by a fibrous capsule. The term adenoma is used as this is a benign epithelial proliferation.
embryonic origins of adrenal medulla
neural crest
the pineal gland
3rd ventricle
regulates circadian rhythm, may also influce onset of gonadal development
“brain said” concretions useful in CT
germinal center
Parathyroid adenoma
identified due to excess hormone secretion (not mass effect)
cell appearance is very close to normal
usually benign
excess hormone may increase blood Ca and bone tunrover
pancreas
How to differentiate zones of the cortex of the adrenal gland?
The zona fasiculata is much more pale staining and you see empty space here. The zona fasciculata cells have lipid components and this is extracted during staining. This is why it looks white. But these cells are also much more puffy looking compared to the cells around them. And finally over here is the zona reticularis.
In the zona fasciculata the cells are in straight cords, in the reticularis you can see much more branching rather than straight lines.
interlobular duct
Thyroid follicle epithelium?
simple cuboidal
What are the 3 classes of hormones?
- steroids
- peptides, polypeptides, proteins
- AA, arachidonic acid analogs and derivatives
parathyroid
Oxyphil cell.
alpha cells
in the periphery
secrete glucagon
papillary fragments
papillary arrangement
fibrovascular core
What does the zona glomerulsa do?
aldo
reg water/electrolytes and thus BP
chief cells
The cells producing the parathyroid hormone are the tiny densely packed darkly staining cells here called chief cells. The parathyroid hormone raises blood calcium levels, it’s antagonistic to calcitonin. What it does is stimulate osteoclasts so that more calcium is released from the bone.
Acidophils
pars distalis (AP)
take up acid stains (eosin)
, secrete GH and prolactin (breast milK)
zona fasciulata - adrenal gland
basophils
thyroid
C cells (parafollicular)
NONE! they release calcitonin when blood Ca is high, prevent bone breakdown by inhibiting osteoclasts
thyroid
Not follicular cells –> C cells –> make calcitonin!
chromophobes
adrenal medulla
filled with secretory granules
in various location
associated with ANS, vascularized, secrete catecholamines
they act as chemoreceptors
Fibrous Capsule. Most insulinomas are benign tumors that do not metastasize.
islets
secrete glucagon (glucose uptake by muscule and storage as glycogen in the liver)
secrete insulin (for glycogen breakdown and glucose release into the blood stream)
secrete somatostatin - inhibits both!
hashimoto’s
autoimmune destruction of follicles by lymphocytes
chronic lymphocyte infiltration –> lymphoid follicles, germinal centers
cuboidal follicle cells –> metaplasia to squamoid with pink cytoplasm
symptoms: cold,fatigue, weight gain, muscle weakness, constipation - due to gland failure! looks like hypothyrpid
medulla
thyroid:
Oncocytic change - Hürthle cell metaplasia (of the follicular cells)
Any idea what this tissue is? It’s cartilage! The larynx. On either side, this odd-looking tissue this is the thyroid gland. And there we have muscles of the nexk. There are two lobes of the thyroid, and the reason it looks like this is because the thyroid contains thyroglobulin, the bright pink substance which is taking up the stain here. It’s enclosed in follicles. The follicles are composed of simple cuboidal cells.
thyroid:
Parafollicular or C cell. Secretes calcitonin.
pars intermedia
anterior pituitary
it has storage depots containing colloid, no one’s quite sure what it’s doing
thyroid:
C cells; calcitonin
Herring bodies
in the posterior pituitary (nervosa)
PAS+ blobs are the storage locations for the hormones sent from the hypothalamus to the pars nervosa. These are called Herring bodies and are a distinguishing factor of the posterior pituitary.
stores hypothalamic hormones (ADH and oxytocin)
ADH - increase water reabsorption in kidneys
Oxytocin - stim uterine contraction and breast alveoli
PP is much less cellular than distalis
Centroacinar cell.
pituitary cell type:
basophil
beta cells
majority
secrete insulin
C cells
in the thyroid gland
In addition to the simple cuboidal cells another population—C cells or calcitonic cells.
, these C cells also secrete calcitonin. Calcitonin is involved in calcium regulation. These C cells (or parafollicular cells), the paler staining ones here they secrete calcitonin when they sense high calcium in the blood. The calcitonin in turn inhibits osteoclasts, prevents them from chewing up bone and releasing calcium into the blood.
Chromaffin cells (of medulla). Origin: neural crest.
Parathyroid. Use the location, posterior or posterolateral to the thyroid, to aid in identification. Not lymph node: no capsule/subcapsular space, no germinal centers.
pancreas with lymph node
This is a high mag of the zona glomerulosa. See the cells are arranged in elongated ovals. They produce mineralocorticoids. Aldosterone, cortisol, corticosterone. Aldosterone acts to help retain water, it raises blood pressure. Along with vasopressin from the pituitary. You can see the much larger zona fasciculata cells, again it has lipids and also releases the corticosteroids.
parafollicular cell
calcitonin
medulary thyroid carcinoma
makes calcitonin
diffuse goiter in hashimoto’s thyroiditis
The dilated end of a neurosecretory neuron containing stored secretory product. Herring body.
Capsule.
And this is a parathyroid. Remember, very small.
Please do not confuse with lymph nodes. Note that there is no capsule, no subcapsular sinus. No regular organization into cortex and medulla.
Much less organized than highly organized lymph nodes, this is instead the parathyroid. The cells are arranged very densely in cords and right here what you’re seeing in this space is adipose tissue. The older you are the more fat you have in your parathyroid.
enteroendocrine cells (DNES - diffuse neuroendocrine system)
regulate motility ad various secretions in the digestive system and respoirtatiory mucosa
Pituitary
B = anterior lobe
Affected organs:
Thyroid (TSH)
Adrenal cortex (ACTH)
Ovary and testis (FSH, LH)
Bones (GH)
Milk glands of breasts (prolactin)
parathyroid
chief cells
secrete PTH
Thyroglobulin or colloid.
General Endocrine Cells
Remember that endocrine cells have no ducts and that the capillary associated for transporting out of the gland is fenestrated or sinusoidal to facilitate this transport.
Parasympathetic ganglion
medullary carcinoma
extracellular amyloid
compressed parathyroid in a parathyroid adenoma
parathyroid
what separates islets from exocrine portions of the pancreas?
reticular fibers
Intercalated duct. (It’s a centroacinar cell.)
thyroid
Parafollicular C Cell. Not involved in thyroid hormone secretion. Secretes calcitonin, involved in caclium homeostasis.
cells in hashimotos?
herthle cells
cytotoxic t cell destruction - breakdown in autoimmunity, autoabs, lymphocytes will destroy thyroid cells
not many follicular cells left (on high power) - low levels of th, high levels of tsh
pars distalis
anterior pituitary
secretes a lot of hormones, all of which except one are secreted in response to releasing factors or hormones from the hypothalamus
Intercalated duct. (It’s a centroacinar cell.)
identify organs and regions
zona glomerulosa
zona fasiculata
zona reticularis
Abundant lipid droplets in the cells = zona fasciculata. (Actually, vacuoles where the lipid droplets were before fixation.)
thyroid:
, these C cells also secrete calcitonin. Calcitonin is involved in calcium regulation. These C cells (or parafollicular cells), the paler staining ones here they secrete calcitonin when they sense high calcium in the blood. The calcitonin in turn inhibits osteoclasts, prevents them from chewing up bone and releasing calcium into the blood.
pituitary gland
multilocar fat
alpha cells of the pancreas
secrete glucagon for glycogenolysis and glucose release into blood stream
on the periphery of islets
zona fasiculata
Embryonic origin of the anterior pituitary?
oropharynx ectoderm (back of mouth)
The anterior lobe is derived from the ectoderm of the pharynx.
thyroid
What are the parts of the anterior pitutary?
pars distalis, which is the largest part of it and in fact the largest part of the gland
the pars tuberalis which wraps around the infindibulum
this pars intermedia
papillary ca
nuclear grooves
nuclei crowded
flat and overlapping
hypothalamic hypophyseal tract
hypothalamic axon to pars nervosa (posterior lobe)
It’s through the infindibulum that the axons will pass into the neurohypohysis.
Islet of langerhans
The entire gland - cortex and medulla are drained by the central vein of the medulla.
parathyroid
thyroid carcinoma (medullary)
insulinoma
chief cells - small, large nucleus, small cytoplasm, secrete PTH
oxyphils - large cytoplasm, unknown function
thyroid
extracellular amyloid
multinodular goiter
Macrophages
Here are the macrophages, that you will see in some of the colloid.
Zona reticularis.
islets of langerhans
excretory duct
Medullary thyroid carcinoma
parafollicular cell origin - produces calcitonin (overproduction)
amyloid - abnormal calcitonin polypeptides in stroma
and what hormones do they make?
acidophils
GH and PROLACTIN
good way to remember: these cells look awfully areolar –> areola = part of the breast –> breast produces milk –> milk makes bebés grow
cd8
CD4, B, Plasma cells but the thing you have the most is cytotoxic CD8 t cells!
in pituitary:
Pituicyte
What is inside thyroid follicles?
thyroglobulin (hormone precursor)
With Iodine and TSH - convert to T3, T4
hashimoto’s thyroiditis
autoimmune destruction of follicles by lymphocytes
You can measure insulin levels, C-peptide levels and stain the tissue for Insulin.
You can also see if the glucose levels remain elevated with fasting.
Chromophobes
in pars distalis (AP)
colorless
granules have probably been released
What are the parts of the posterior pituitary?
pars nervosa, the large bulbous part
the infindibulum, which is connected to the hypothalamus
Hurthle cells
in hashimoto’s thyroiditis
cuboidal follicle cells –> metaplasia to squamoid with pink cytoplasm
oncocytic change
Embryonic origin of the posterior pituitary?
neuroectoderm (part of brain) - remains connected to the brain
Basophils
in pars distalis (AP)
take up basic stains (hematoxilin, PAS)
secrete TSH, ACTH, FSH, LH
graves disease
hyperplasia
not much colloid (cells are active and hypertrophic and using reservoirs of thyroglobulin)
lots of cells - pile up and give appearance
vaculated effect in colloid - more cells, less colloid
embryonic origins of adrenal cortex?
mesodermal derivative
pars nervosa
of the posterior lobe, connects to infindibulum
not classic endocrine tissue in that it does not actually secrete its own hormones. They are produced in hypothalamus in these nuclei whose names you are not currently responsible for.
The nuclei in the hypothalamus secrete the hormones as granules, these travel along what are actually axons into the pars nervosa. They are stored in granules until such time as they need to be released. So the pars nervosa is really a storage space
the pineal gland
It’s located deep in the brain in the third ventricle. Reculates your circadian level, your day-night cycle, probably responsible for jetlag etc. Secretes melatonin. Called pineal because shaped like a pine cone. It tapers a little bit at the bottom. Requires a lot of imagination to see it looks like a pine cone. Interesting substance contained—brain sand, actually concretion of calcium carbonate and phosphate. No one knows what it’s doing here, increases with age. Brain sand clumps can be useful for orienting yourself on a CT scan.
basophils (B)
secrete TSH
Nervous tissue.
adrenal gland
lymph node
