Anatomy & Physiology

(MCQ) Not true about islets of langerhans? A- b cells secrete insulin and is evenly distributed B- A cells secrete glucagon predominant in body and tail C-D cells secrete somatostain D-F cells secrete PP and is predominant in head of pancreas

Explanation:

F cells - PP = Uncinate process [not head]

(MCQ) First endocrine cells to appear in embryo ?

• A- A cells
• B- B cells
• C- C cells
• D- D cells

(MCQ) Not true about development of pancreas

• A- Pancreas begins development during 4-5th week of gestation
• B-Ventral bud appears first and form uncinate process
• C- Dorsal bud develops into body and tail of pancreas
• D-clockwise rotation occurs during 4-8 week of gestatation

(MCQ) Duct of Wirsung is formed by? A- Dorsal pancreatic bud along with proximal portion of ventral pancreatic bud B- Dorsal pancreatic bud along with distal portion of ventral pancreatic bud C- Ventral pancreatic bud along with distal portion of dorsal pancreatic bud D-Ventral pancreatic bud along with proximal portion of dorsal pancreatic bud

Explanation:

• Ductal development:
  • Duct of Wirsung: ventral pancreatic bud+ distal part of Dorsal pancreatic bud •
  • Duct of Santorini: Proximal portion of dorsal pancreatic bud
• Pancreas development
  • PDX1 and PTF1a-induce pancreatic differentiation
  • Dorsal pancreatic bud- Suppression of sonic hedgehog pathway
  • Ventral pancreatic bud- cardiogenic mesenchyme-lack of FGF- leads to ventral pancreas development by default

(MCQ) Genes responsible for endocrine differentiation in pancreas ?

A-PDX1 B- PTF1 C-NEORG3 D-None of these

Genetics:

• NEORG 3- earliest marker specific to endocrine differentiation(NOTCH SIGNAL PATHWAY)
• PDX1- earliest marker for pancreatic progenitors ; Required for B cells functions
• PTF-1- promotor of acinar fate

• PAX4-endocrine differentiation

  

Genes involved in Early Liver, Bile Duct and Pancreas Development:

(MCQ) No of sphincters in Sphincter of Oddi at ampulla = 3 or 4 controversial

• Accd to Blumgart = 3 Sphincters:
  • Sphincter of Oddi
  • Sphincter of choledochus of Boyden
  • Sphincter pancreaticus

Blood supply of Pancreas

(MCQ) • Arteria pancreatica magma (greater pancreatic artery) is a branch of ? A - Splenic artery B-SMA C-GDA D-Left gastric artery

Inferior pancreatic artery = transverse pancreatic artery

• Blood supply :
  • GDA---SPDA----Anterior & Posterior
  • SMA- IPDA ----Anterior & Posterior
  • Splenic artery- Greater pancreatic artery, transverse pancreatic artery, dorsal pancreatic artery, caudal pancreatic artery

Uncinate Process:

(MCQ) Not true about uncinate process of pancreas ?

A- Develops from ventral pancreas B- Related to SMA medially C-Posteriorly related to left kidney, left renal vein and adrenal gland D-All of above

Explanation:

• Medially = SMV and laterally SMA

ENDOCRINE FUNCTION:

INSULIN SECRETION:

(MCQ) All of following increases insulin secretion except ?

• A-GIP
• B-Ach
• C-leptin
• D-glutamate

Explanation:

• Stimulate insulin secretion:
  • Glucose, amino acid (arginine, glutamate)
  • Incretins = GIP and GLP 1
  • Ach ( non neuronal pathway)
• Inhibit insulin secretion:
  • Sympathetic pathway : Substance P, VIP, neurotensin
  • Somatostatin, amylin, leptin, pancreastatin
• GLUT 1 and GLUT 3 in beta cells in human
• Acute pancreatitis and diabetes
• 15% develop within 12 month of AP
• Independent from severity of pancreatitis
• 40% risk after hospitalization for first episode

(MCQ) Not a function of insulin ? A- lipogenesis B-Protein synthesis C-hepatic gluconeogenesis D-glycogenesis

Explanation:

• Insulin- energy storage
• uptake of amino acid and glucose
• Decrease lipolysis
• Glycogenesis

INCRETIN:

(MCQ) Not true about incretins ?

• A- secreted by L cells of small intestine in response to rise in plasma glucose
• B-GLP-1 stimulates insulin and inhibits glucagon secretion
• C- gastric emptying is decreased
• D-All of above

Explanation:

• Incretins are secreted due to enteric response of glucose [not secreted by IV glucose]
• 2 incretins:
  • GIP = K cells of duodenum ; Inhibit gastric acid and Pepsin secretion
  • GLP 1 =L cells of ileum, colon, rectum ; inhibit P. Glucagon release & Increase food transit time in stomach
• Stimulate insulin in response to enteral stimulation
• Enteral stimulation > parenteral stimulation
• inhibit gastric emptying
• Inhibit glucagon secretion
• Gliptins ( Sitagliptin) GLP-1 analogue in management of DM

EXOCRINE FUNCTION:

(MCQ) true about exocrine function of pancreas?

A-S cells in duodenum secrete secretin which primarly stimulate acinar cells to secrete pancreatic enzymes B-CCK is stimulated by I cells of duodenum and jejunum in response to acidic chyme C- Pancreatic enzyme secretion is primarly stimulated by sympathetic stimulation D-DNAse, RNAse and amylase does not require activation in duodenum

Explanation:

• Cephalic phase, gastric phase, intestinal phase
• Secretin -
  • S cells of duodenum
  • centroacinar and ductal cells to release fluid and bicarbonate, increases blood flow.
  • Lesser extent on acinar secretion (enzymes)
• CCK-
  • I cells of duodenum and jejunum
  • CCK---neurons--- Ach---M1 &M3 receptors----enzyme secretion
  • Fatty acids, and amino acids stimulate I cells
  • Enzymes Secretion = acinar cell stimulation
• Active form :
  • DNAse, RNAse, Amylase and lipase
  • only 4 enzymes are secreted in active form