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FUNCTION/DYSFUNCTION

OF ENDOCRINE PANCREAS

Diabetes

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Anatomy of the pancreas:Both an exocrine and endocrine organ

Cells with exocrine function release analkaline fluid containing sodiumbicarbonate and enzymespancreatic duct

small intestinePancreatic juice aids in breakdown anddigestion of food in the small intestine

Pancreatic exocrine cells = acinar cells

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Endocrine Function :

Cells of the Islet of Langerhans synthesizeand release hormones into the circulation.

Hormones travel through the bloodstream to

target tissues (especially liver and muscle)At the target cells, hormones bind specificreceptors and cause cell changes that control

metabolism

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Pancreatic endocrine cells regulatecarbohydrate, fat, protein metabolism:

Alpha cells secrete the hormoneglucagon

Beta cells secrete the hormones

insulin and amylin Delta cells secrete the hormones

gastrin andsomatostatin

F cells - secrete hormone pancreaticpolypeptide

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Beta Cells

Synthesize pre-proinsulin, a proteinThis is cleaved by enzymesproinsulin, thencleaved again insulin

Insulin is the biologically active hormone thatis released into the bloodstream

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Insulin secretion is controlledthrough several mechanisms:

Chemically high levels of glucose andamino acids in the blood

Hormonally beta cells are sensitive toseveral hormones that may inhibit orcause insulin secretion

Neurally stimulation of theparasympathetic nervous system causesinsulin to be secreted.

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Insulin secretion is decreased by:

Decreased blood glucose concentration Increased blood insulin concentration Sympathetic stimulation

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Blood glucose is decreased becauseinsulin causes glucose to leave thebloodstream and enter the metabolizingcells.

With the exception of brain, liver and

erythrocytes, tissues require membraneglucose carriers.

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Modern classifications (Table17.7)Type 1 or IDDM - Insulin Dependent Diabetes

Mellitus

Type 2 or

NIDDM - Non-Insulin Dependent DiabetesMellitus

Other Types of Diabetes Mellitus

GDM - Gestational Diabetes Mellitus

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Accounts for 10% all DM in the Western world

~10-15% have parent or sibling with thedisease

Peak age of diagnosis = 12 years

Genetic/environmental/autoimmune factorsdestroy beta cells

Believed abrupt onset now immunomarkers andpreclinical symptoms have been discovered

Type 1 or IDDM

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Clinical Manifestations:Weight loss - Patient eats, but nutrients are

not taken up by the cells and/or are notmetabolized properly

Osmotic diuresis results in fluid loss

Loss of body tissue by metabolism of fatsand proteins

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NIDDM insulin resistance in target cells

See decreased cell responsiveness

Decreased insulin secreted by cellsAlso abnormal amount of glucagonsecreted

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Treatment :

provide glucose (I.V. or subcutaneous ifunconscious)

Observe for relapse

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Treatment:- low dose insulin

Also, administer fluids, electrolytes

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Microvascular disease chronic diabetesw/ improper glucose metabolism

thickening of the basement membrane ofcapillaries, particularly in the eye and thekidney. As the capillary changes in this

way, Decreased tissue perfusionSo ischemia hypoxia

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In the eye the retina is metabolically quite active,so hypoxia here is a big problem

So see:Retinal ischemia

Formation of microaneurisms, hemorrhage,

tissue infarct, formation of new vessels,retinal detachment

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