Pancreas and pituitary Flashcards
Pancreas
covered by a thin CT capsule which sends in septae, dividing the organ into indistinct lobules
Parenchyma + stroma
Exocrine pancreas
Oval circles contain pyramidal-shaped acinar cells that secrete enzymes
Pancreatic acinar cells
Blue: basal nuclei
pink: apical secretory granules
Centroacinar cell
First part of the duct system
Tend to bulge into acinus
Secrete a watery, bicarb-rich solution
Pancreas excretory duct system
Centroacinar –> intercalated ducts –> intralobular ducts –> interlobular ducts
Epithelium gradually changes from simple cuboidal to low columnar, also accumulate more CT
Endocrine pancreas
Islet of Langerhans
CT capsule, pale-staining cells (green stars)
fenestrated capillaries
reticular CT
Beta cells
Special stains
antibody against insulin - brown
Pituitary
Anterior on top:
- main bulk - anterior lobe/pars distalis
- thin caller around infundibular stalk - pars tuberalis
- narrow vestibular band of tissue in contact with posterior pit - intermediate lobe
Posterior (neurohypophysis)
- main bulk: posterior lobe/pars nervosa
- infundibular stalk
Posterior pituitary
Sinusoidal capillaries seen
Blue stars = unmyelinated neuronal axons (bodies in hypothalamus)
Herring bodies (green): dilate terminal axons, store neurosecretory vesicles (oxytocin, ADH), appear eosinophilic, in close contact wiht sinusoids
Yellow arrows: pituicytes - support surrounding neurosecretory axons
Yellow: chromophobes
- little cytoplasm, can only see nuclei,
Green: chromophils
- abundant cytoplasm with secretory granules - active/stain well
within chromophils:
red: acidophils - smaller, secrete GH and prolactin
blue: basophils - larger with granular cytoplasm, secrete ACTH, FSH, LH, TSH
Pineal gland
at the floor of the 3rd ventricle
Pineal gland
Green: pinealocytes - source of melatonin, pale nucleus with visible nucleoli
Yellow: supportive cells - smaller, darker
brain sand: mineralized extracellular concretions with unknown function, increases with age, can be seen on Xray as landmark
