ENDOCRINOLOGY (pancreas)

Pancreas
1. The pancreas has both endocrine and exocrine funtions
  1. The islets of Lngerhans include alpha cells, beta cells and delta cells
    1. Alpha cells secrete glucagon
      1. More predominant effect than insulin
      2. Increased by sympathetic signals, adrenaline secretion and decreased plasma glucose
      3. Effects on the liver include increased gluconeogenesis and increased protein breakdown. Causes increased lipolysis in adipose tissue
      4. Glucagon secreted in the post-absorptive/ catabolic state when energy stores are metabolised
    2. Delta cells secrete somatostatin
    3. Beta cells secrete insulin
      1. Increased by parasympathetic signalling, increased plasma glucose and amino acid levels
      2. Insulin dominates in absorptive/ anabolic state. This is the period just after eating when energy is stored in macromolecules
      3. Effects on the liver include decreased gluconeogenesis and increased triglyceride synthesis. In the muscle it causes increased glycogen synthesis and decreased glycogenolysis. Also decreased lipolysis in adipose tissue
        Increased glucose uptake by GLUT4 transporter translocation
  2. Secretes digestive enzymes from acini
2. Normal blood glucose = 70-140mg/dl
  1. Hypoglycaemia
    1. Symptoms include sweating, pounding heart, shaking, confusion, visual disturbance
    2. Treated with oral or IV glucose or glucagon
  2. Hyperglycaemia
    1. Type 2 - insulin resistance at target tissue or impaired insulin secretion
      1. Firstly managed by lifestyle factor changes
      2. Drug treatments include sulphonylureas that increase insulin secretion, thiazolidinediones (TZD's) that reduce insulin resistance, as do biguanides (Metformin)
        Sulphonylureas block K+ ATP channels so cause depolarisation and therefore release of insulin
        TZD's bind to PPAP-y receptors; more GLUT4 transporters
      3. Orlistat can be taken to reduce weight
      4. Long term complications
        Diabetic nephropathy - end stage renal failure needs transplant
        Diabetic neuropathy - nerve conduction velocity slowed to lower limbs. Effects sensation to pain
        Diabetic retinopathy - increases cataracts due to thickened membrane of retinal blood vessels
    2. Type 1 - beta cell destruction so inability to produce insulin
      1. Autoimmune destruction of beta cells
      2. Treated by mimicking exogenous insulin administered subcutaneously around meal times
        Can be short acting (Ispro), delayed (Lente) or long acting (Ultralene')
    3. Diagnosed by: 1.symptoms 2. random plasma glucose >200mg/dl 3.fasting plasma glucose >126mg/dl 4. Oral glucose tolerance test >200mg/dl after 2hours

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ENDOCRINOLOGY (pancreas)

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	Erstellt von Alix Stonehouse vor mehr als 9 Jahre