PANCREAS Has exocrine amp endocrine functions Parts Capsule Septa lobules Secretions Enzymes Hormones EXOCRINE PANCREAS COMPOUND ACCINAR GLAND Pear shaped accini 58 pyramidal cells ID: 593709
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Slide1
HISTOLOGY OF PANCREASSlide2
PANCREAS
Has exocrine & endocrine functions
Parts
Capsule
Septa – lobules
Secretions:
Enzymes
Hormones Slide3
EXOCRINE PANCREAS
COMPOUND ACCINAR GLAND
Pear shaped accini
5-8 pyramidal cells
Reticular fibers support accini
Inter- lobular CT contains:
Blood vesselsNerves Lymphatic Slide4
EXOCRINE PANCREAS
ACCINI
Cells have spherical basal nucleus
Basal cytoplasm basophilic –RER
mitochondria
Golgi apparatus
Apical zymogen granules – maximum in fasted personCentroacinar cellsSlide5Slide6
EXOCRINE PANCREAS
DUCTS
Intercalated ducts
NO
striated ducts
Large intralobular ducts –high cuboidal epithelium
Interlobular ducts – columnar epitheliumLarger ducts
Main ductSlide7
SECRETIONS OF EXOCRINE PANCREAS
Proteases (trypsinogen & chymotrypsinogen etc.)
Amylase
Lipase
Nucleases (DNAase & RNAase)Slide8
MEDICAL APPLICATION
ACUTE NECROTIZING PANCREATITIS
Proenzyme activated
Digest pancreatic tissue
Causes:
Alcoholism
Gall stonesTrauma Drugs Slide9
MEDICAL APPLICATION
Extreme malnutrition e.g. kwashiorkor
Atrophy of pancreatic
acinar
cells
Loss of RER
Digestive enzyme production hinderedSlide10
ENDOCRINE PANCREAS (ISLETS)
Embedded within accini
100-200µm diameter
> 1 million islets
Abundant in tail Slide11
ISLETS OF LANGERHANS
Reticular fibers surround each islet
Small polygonal cells
Cells lightly stained
Arranged in anastomosing cords
Fenestrated capillaries between cords
Autonomic fibersSlide12
ISLETS OF LANGERHANS
CELLS OF ISLETS
A /
α
cells- glucagon, at periphery
B /
β cells- insulin, at center-numerousD /
δ
cells-
somatostatin
, scattered
F /PP cells- pancreatic polypeptide
Enterochromaffin
cells-
motilin,secretin
,
substane
-PSlide13
BLOOD SUPPLY
Rich arterial supply
Major BV run in interlobular CT
Intralobular BV
Arterioles pass to islets
Extensive capillary network
First supply peripheral cellsBlood from islets pass to supply exocrine tissueHormones effect acinar functionSlide14Slide15
COMPARISON
PANCREAS
PAROTID GLANDSlide16
MEDICAL APPLICATION
INSULIN DEPENDENT / TYPE I DIABETES (juvenile)
Autoimmune disease
Partial or total destruction of
β
cells
Lack of insulinINSULIN INDEPENDENT DIABETES / TYPE IIAdult onsetAssociated with obesityFailure of cell to respond to insulinTUMOURS OF ISLETSMay secrete anyone of the hormonesMay secrete more than one hormone