Histology ES 4

malakissa's version from 2016-01-21 18:31


Question Answer
thyroid gland is surrounded by Dense "irregular" connective tissue capsule !! imp
capsule will send the septa & this septa will Divide the gland intolobules
lobules of“follicles” Which contain the colloid “thyroglobulin”
septa carry the blood vessels, lymphatic vessels & nerves
thyroglobulin is a large gelatinous protein
thyroid gland organizationThyroid gland showing the lumen of the Follicles which are surrounded by follicular Cells that ranges from squamous to low Columnar “depending on the activity”
Squamous follicular cells activitynot active => no secretion
Columnar follicular cells activityactive => there is secretion
C cells are originated from neural Crest (so they appear pale in color)
C cells secretcalcitonin “controls calcium metabolism
parenchymal cells of gland that are same / different staining affinity different in staining affinity
follicular cells appear small & darkly stained
& C cells “parafollicular cells” appear large & lightly stained (can be binucleated).
C cells are found either between the Follicles or interspersed between follicular cells but it’s above the basement membrane in both conditions
Follicular cells apically contain microvilli + lysosomes + mitochondria (mmla)
Follicular cells basally they contain RER and Golgi
follicular cells that have pseudopods “microvilli” to increase the surface area & increase the amount of secretion
C cells that contain calcitonin containing granules
when follicular Cells are extremely active they arecolumnar, pinocytic vesicles are seen, colloid amount is low.
functional chief cells are lighty /darkly satined & the older oxyphil cells are lightly/darkly stained.darkly,lightly
cells of tyroid glandfollicular + C "paraFollicular" /clear cells
cells of parathyroid glandprincipal/cheif cells / oxyphil
paryncymal cells of the parathyroid glands are called chief cells “prenciple cells”
“prenciple cells” secrete parathyroid hormone (PTH)
when they become older they will be non-functional oxyphil cells (ana b7ke less functional)
oxyphil cells that are smaller/ larger than principallarger
oxyphil cells organized as single cells or as clumps “Clusters”
There is a clue to know that this is parathyroid gland which is the adipocytes,
adipocytes in parathyroid gland increase/decrease with ageincrease
oxyphil cells secrete PTH but in very low amount
principal cells Chief cells shape central rounded nuclei are lightly acidophilic but "Darkly Basophilic"
principal cells functionalitythey are functional so they have a lot of ribosomes(basophilic) to synthesize the parathyroid hormone (PTH).
Oxyphil cells vs P cellswill be more acidophilic and larger
islets of Langerhans cells arrangment the cuboidal cells are arranged in cords around the capillary plexus
each islet is surrounded by a thin layer of reticular capsule to separate it from the acinar exocrine pancreas
islets of Langerhans cells ccc where the cells are small & polygonal or rounded in shape & lighter than the surrounding acinar cells.
islets of Langerhans lighter/darker than the surrounding acinar cellslighter
The reticulin protein along the capsule & Around the capillaries is stained green
Alpha (α) cells IHbrownish-reddish (blackish) in color, in the peripheral (DR said Black)
Beta (β) cells IHbrownish-orange in color, in the center (DR said pale reddish)
Immunohistochemical section of the islets of Langerhans where a >>>>modified aldehyde fuchsin stain<<<< is used to detect the granules of only two types of cells in the islets alpha & beta
Immunohistochemical stain used to detect alpha & beta cells in pancreasemodified aldehyde fuchsin stain
Pineal Gland clueBrain sand (or acervuli cerebri or - just for good measure - corpora arenacea).
Brain sand (or acervuli cerebri or - just for good measure - corpora arenacea are calcium-containing concretions in the pineal parenchyma, which increase in size and number with age.
calcium-containing concretions in the pineal parenchyma are radioopaque,
and, since the pineal is located in the midline of the brain benefit in thatthey provide a good midline-marker.
pinealocytes: large, light and round nuclei, secrete melatonin.
pinealocytes secretmelatonin.
Interstitial cells: astrocyte-like glial cells; dark, elongated nuclei
Pinocytic vesicles (scalloped appearance) = a sign of activity