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List the major arteries of the pancreas.
- - Most arise from celiac trunk.
- -Anterior/posterior pancreaticoduodenal arteries branch from gastroduodenal.
- - Inferior pancreaticoduodenal anastomoses with SMA.
- - Dorsal pancreatic from proximal splenic
- - Greater pancreatic from distal splenic
- - Transverse pancreatic from dorsal/greater supply inferior aspect of body/tail
At what vertebral level does the pancreas sit?
Blood tests for pancreatic function?
- - Serum amylase
- - Serum lipase
- - CRP
- - FBC, U+Es, blood glucose, ABG, plasma calcium
Briefly describe the process of alcohol-induced pancreatic fibrosis.
- 1. Alcoholic byproducts cause pancreatic acinar cell damage.
- 2. This causes inappropriate trypsinogen activation.
- 3. Cytokine release
- 4. Stellate cell activation causes release of collagen and fibronectin
- 5. Fibrosis
What enzymes are synthesised in the pancreas?
- - Proteases: trypsinogen and chymotrypsinogen (zymogens)
- - Pancreatic lipase
- - Amylase
Which surfaces of the pancreas are covered in peritoneum?
Anterior surface of the pancreas; the pancreas is a retroperitoneal organ.
In which types of cells are insulin and glucagon secreted from?
- - Insulin is secreted from beta cells.
- - Glucagon is secreted from alpha cells
- - Both alpha and beta cells are located within Islets of Langerhans.
List the stages of insulin production.
- 1. Preproinsulin N-terminus is removed to form Proinsulin2. C chain of Proinsulin is removed to form Insulin.
List mediators of Beta cell activation.
- - Increases in:
- - blood glucose
- - amino acids
- - fatty acids
- - GIP
- - CCK
- - Acetylcholine
- - VIP
- - Decreases in:
- - somatostatin
- - ghrelin
- - NPY
- - nor/epinepherine
What physical property is required for optimal production of insulin within the islets?
- - Cell-to-cell contact.
- - 6 connexins form a connexon. Connexons of one cell dock to the connexon of an adjacent cell, mediated by E-cadherin.
- - Result is clusters of 20-30 beta-cells producing insulin
List the 4 main types of glucose receptor and describe each.
- - GLUT1: expressed in erythrocytes and BBbarrier.
- - GLUT2: bidirectional transporter, expressed in liver, renal tubule, pancreatic beta-cells, s.intestine. Transports glucose, galactose and fructose into portal system from intestinal mucosa.
- - GLUT3: Expressed in neurons
- - GLUT4: Major transporter in muscle and adipose tissue. Insulin-dependent.
How does a lack of insulin lead to ketone formation?
- 1. Lack of glucose entering muscle cells causes body to utilise fats as energy substrate.
- 2. Adipose releases triglycerides.
- 3. Broken down into FFAs.
- 4. FFAs enter liver cells.
- 5. FFAs are converted into fatty acyl carnitine.
- 6. FACarnitine is coverted into Acetyl CoA in mitochondria.
- 7. A.CoA > Aceloacetate > Acetone / Beta-Hydroxybutyrate
NB - Acelocetate and B-Hydroxybutyrate cause H+
dissociation and result in metabolic acidosis
Why should potassium levels be checked before giving insulin to a T1DM patient?
- - Insulin activates the NA/K ATPase, causing a flux of potassium into cells.
- NB - Serum potassium should be > 3.3mEq/L before initiating insulin therapy.
Briefly describe the types of insulin available for diabetic patients.
- - Short-acting insulin:
- Used for premeal injection in multiple-dose regimens. These analogues act and disappear more rapidly than human insulin.
- - Intermediate and long-acting insulin:
- Action of human insulin can be prolonged with addition of zinc or protamine. Can be premixed with soluble insulin.
What are the normal blood glucose ranges, before and after meals?
- - Before: 4-7mmol/L
- - After: 4-10mmol/L