Sonography Chapter 14: Pancreas Anatomy and Function

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Questions and Answers

What percentage of the pancreas is responsible for endocrine function?

20%

15%

10% (correct)

Which type of cell in the Islets of Langerhans produces the hormone glucagon?

Delta cells

Beta cells

Gamma cells

Alpha cells (correct)

What is the main action of insulin produced by beta cells?

Protein to glucose

Glycogen to protein

Glycogen to glucose

Glucose to glycogen (correct)

Which artery branch supplies the head and part of the duodenum?

Pancreaticoduodenal Artery Signup and view all the answers

What is the function of somatostatin produced by delta cells?

Inhibit alpha and beta cells Signup and view all the answers

What is the function of ghrelin produced by epsilon cells?

Related to blood sugar regulation Signup and view all the answers

Where is the pancreas located in the body?

In the retroperitoneum in the epigastric region Signup and view all the answers

Which part of the pancreas is more inferior to the body and tail?

Head Signup and view all the answers

What is a characteristic of the echotexture of the pancreas?

Homogenous with a mottled appearance Signup and view all the answers

What is the usual echogenicity of the pancreas compared to the liver?

Isoechoic or hyperechoic Signup and view all the answers

Which tributary of the pancreas is mentioned in the text?

Splenic vein Signup and view all the answers

What happens to the echogenicity of the pancreas with age?

It increases Signup and view all the answers

In which region of the body does the pancreas lie?

Midline Signup and view all the answers

What is the primary function of the exocrine tissue in the pancreas?

Secretion of pancreatic juice to aid digestion Signup and view all the answers

What is the name of the main pancreatic duct that collects pancreatic juice?

Duct of Wirsung Signup and view all the answers

What is the function of the enzyme amylase in pancreatic juice?

Breakdown of carbohydrates into smaller molecules Signup and view all the answers

What percentage of the pancreas is composed of exocrine tissue?

90% Signup and view all the answers

What is the function of the hormone glucagon in the pancreas?

Regulation of blood sugar levels Signup and view all the answers

What is the name of the structure that allows pancreatic juice to pass into the duodenum?

Ampulla of Vater Signup and view all the answers

What is the function of the enzyme trypsin in pancreatic juice?

Breakdown of proteins into smaller molecules Signup and view all the answers

During a pancreatic ultrasound, what is the recommended duration of fasting for the patient?

6 to 8 hours Signup and view all the answers

What frequency transducer is typically used for pancreatic ultrasound?

3.5 to 5 MHz Signup and view all the answers

In which plane is the entire pancreas typically visible?

Transverse Signup and view all the answers

What is the primary position used for pancreatic imaging?

Supine Signup and view all the answers

In which direction should the transducer be swept during transverse imaging?

Superiorly to inferiorly Signup and view all the answers

What is the purpose of imaging the pancreas in both transverse and sagittal planes?

To demonstrate the head, body, and tail Signup and view all the answers

What is the typical length of the adult pancreas?

12-18 cm Signup and view all the answers

What is the diameter of the head of the pancreas in the anteroposterior direction?

2-3 cm Signup and view all the answers

What is the location of the gastroduodenal artery in relation to the head of the pancreas?

Anterior lateral aspect Signup and view all the answers

What is the name of the duct that dumps secretions into the duodenum via the major papilla?

Main Pancreatic Duct or Duct of Wirsung Signup and view all the answers

What is the typical size of the main pancreatic duct?

3 mm or less Signup and view all the answers

What is the location of the splenic vein in relation to the tail of the pancreas?

Posterior to the tail Signup and view all the answers

What is the landmark that helps to identify the body of the pancreas?

Superior Mesenteric Artery Signup and view all the answers

What is the appearance of the main pancreatic duct on ultrasound?

Anechoic Signup and view all the answers

Study Notes

Pancreas Anatomy and Function

Lies in the midline, in the epigastric region, and composed of exocrine and endocrine tissue (90% exocrine, 10% endocrine)
Performs two main functions: exocrine and endocrine

Exocrine Function

Acini cells make up 90% of the pancreas and perform exocrine functions
Produces pancreatic juice containing:
- Amylase (breaks down carbohydrates)
- Lipase (breaks down fats)
- Trypsin, chymotrypsin, and carboxypeptidase (break down proteins)
- Nucleases (break down nucleic acids)
- Sodium bicarbonate (buffers hydrochloric acid)

Endocrine Function

Islets of Langerhans consist of alpha, beta, delta, gamma, and epsilon cells, which secrete hormones directly into the bloodstream
Hormones and their actions:
- Insulin (beta cells): glucose → glycogen
- Glucagon (alpha cells): glycogen → glucose
- Somatostatin (delta cells): inhibits alpha and beta cells
- Pancreatic polypeptide (gamma cells): related to blood sugar regulation
- Ghrelin (epsilon cells): related to blood sugar regulation

Vascularity

Arterial supply:
- Pancreaticoduodenal artery (branches of gastroduodenal artery) supplies the head and part of the duodenum
- Branches of the splenic artery supply the body and tail
Venous drainage:
- Tributaries of the superior mesenteric vein (SMV) and splenic vein

Pancreas Structure

Divided into four regions: head, neck, body, and tail
Head: more inferior (caudal) to the body and tail, with the uncinate process considered part of the head
Body: more superficial than the head and tail
Tail: more superior and posterior to the spleen

Sonographic Parameters of the Pancreas

Varies widely in echogenicity, texture, shape, and size
Echogenicity: usually isoechoic or hyperechoic to the liver, increasing with age
Echotexture: homogenous, can have a mottled appearance
Size: varies, comparable between sexes, decreasing with age
Shape: varies in shape, with a smooth or lobulated contour

Landmarks for Identifying the Pancreas

Head: gastroduodenal artery, common bile duct, and inferior vena cava
Neck and uncinate process: anterior to the superior mesenteric vein (SMV) and portosplenic confluence
Body: superior mesenteric artery, splenic vein, and aorta
Tail: splenic vein lies posterior to the tail, with the splenic artery seen in cross-section

Pancreatic Ducts

Main pancreatic duct or duct of Wirsung: usually merges with the common bile duct before entering the duodenum at the major papilla
Accessory duct or duct of Santorini: seen on ultrasound, less than 3 mm in size
Ducts are anechoic (fluid-filled) and seen as linear structures in the pancreas body

Scanning the Pancreas

Typical scan: 3.5 to 5 MHz transducer, fasting patient, and imaging in 2 planes (transverse and sagittal)
Windows used: supine, right anterior oblique, left lateral decubitus, and left coronal
Transverse images: demonstrate the head, body, and tail, with interrogation and imaging from superior to inferior
Sagittal images: demonstrate the head, body, and tail separately, with interrogation from the body to the head and back to the body, then to the tail and back to the body

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Description

This quiz covers the basics of pancreas anatomy and function, including sonographic landmarks and normal parameters. It also explores how to scan the pancreas and its appearance. Based on Chapter 14 of Sonography: Introduction to Normal Structure and Function, 5th edition.