SA Anatomy Refresher Flashcards
Recap the anatomy and function of the pancreas
- The pancreas is a tubuloalveolar gland and has exocrine and endocrine tissues. The exocrine is the larger of the two parts and secretes pancreatic juice; a solution containing enzymes for carbohydrate, protein and triacylglycerol digestion. Pancreatic juice drains into the small intestine where it is functional. The endocrine part secretes hormones for the regulation of blood glucose concentration, including insulin, glucagon and somatostatin. The functional units of the endocrine part are the islets of Langerhans.
- The pancreas is located in the craniodorsal part of the abdomen in close association with the duodenum. It can be divided into three parts; a body and left and right lobes. The lobes are loosely united by interlobular connective tissue. Connective tissue contains blood vessels, nerves and lymphatics. Generally, the portal vein runs between the left and right lobes (see species differences). The pancreas is roughly “V” shaped in all species.
What enzymes are released from the pancreas and what are their actions?
How does the anatomy of the pancreas differ in dogs and cats?
- Carnivores have a pancreas that is clearly distinguishable as a body and left and right lobes. The portal vein runs dorsally between the left and right lobes. The left lobe is smaller than the right. The tip of the left lobe contacts the left kidney and lies in the greater omentum. The right lobe follows the descending duodenum and lies in the mesoduodenum. Dorsally, it is related to the visceral surface of the liver and the ventral surface of the right kidney. Ventrally, it is related to the descending duodenum. Laterally it is related to the ascending colon. In dogs, both pancreatic and accessory ducts persist throughout development. However, the pancreatic duct is smaller. It joins the bile duct just before opening into the major duodenal papilla which lies 3-6cm distal to the pylorus of the stomach. The accessory duct is the bigger duct and opens 3-5cm further distally to the pancreatic duct. The two ducts communicate inside the pancreas.
- In cats, the distal part of the accessory duct atrophies during development, so only the pancreatic duct persists. Cats normally have pacinian corpuscles in the interlobular tissue that are visible grossly being 1-3cm in diameter. Dogs and cats produce little pancreatic juice between meals, but lots during a meal
A 6 year old MN dog presents with a history of subtle weight gain and increasing lethargy/slowing up on walks over the last 4-6 weeks. He had a seizure over the weekend. A blood test at the time showed a blood glucose of 1.1mmol/l and an insulin assay run on a blood sample taken at the same time gave a result just above the normal reference range.
What is your suspected diagnosis?
Insulinoma?
Thinking about the anatomy of the oesophagus- where are the most likely sites for an obstruction to occur?
Objects usually lodge in the areas of the esophagus with the least distensibility: the thoracic inlet, over the heart base, or the caudal esophagus just cranial to the diaphragm. Occasionally, an object may lodge in other locations such as the upper esophageal sphincter
The cervical oesophagus is a common site to place a feeding tube in small animal patients.
What important anatomical features do you need to be aware of in the region of the cervical oesophagus if you are going to minimise risks associated with oesophagostomy tube placement?
Vagal nerve
Larynx
Thyroid
Trachea
Carotid artery
Jugular vein
Recurrent laryngeal nerve
Where is a common site to place a feeding tube in SA patients?
Cervical oesophagus
Which side of the neck would you choose to insert an oesophagostomy tube and why?
Clip and scrub the left side of the neck. The cervical oesophagus lies closest to the left side.
Where might a corn cob foreign body lodge in a Labrador that scavenged the bin after a barbecue? Assume the foreign body managed to get down the oesophagus and in to the stomach.
normally at the outflow of the stomach or in the small intestine
Where does the bile duct enter the duodenum?
The common bile duct (CBD) of the dog opens near the minor pancreatic duct at the major duodenal papilla, and the accessory pancreatic duct opens a few inches distally. In the cat, the CBD fuses with the pancreatic duct just before entering the duodenal papilla 3 cm caudal to the pylorus
What is gastric torsion/volvulus?
Which breeds is it mostly seen in?
Peracute, rapidly fatal syndrome resulting from abnormal accumulation of gastric ingesta and gas (dilatation) which may precipitate rotation of the stomach (volvulus).
Most common in the German Shepherd Dog, Irish Setter, Great Dane and other giant breeds.
What are the clinical signs of a gastric torsion?
- Retching, unproductive vomiting efforts and hypersalivation.
- Rapid anterior abdominal distension.
- Circulatory collapse and dyspnea.
- Concurrent pathophysiological changes include: hypovolemic shock, electrolyte and acid-base abnormalities, gastric necrosis, cardiac arrhythmias, endotoxemia.
What is the diagnosis for a gastric torsion?
history, signs; priority is to differentiate simple dilatation from that complicated by volvulus.
What is the treatment for a gastric torsion?
- Gastric decompression.
- Treat shock and stabilize patient.
- Restore gastric anatomy and create a gastropexy.
- Surgery is no substitute for inadequate shock therapy.
What are the presenting signs for a gastric torsion?
- Retching, unproductive vomiting efforts and hypersalivation.
- Rapid abdominal distension.
- Restlessness.
- Ptyalism.
- Non-productive retching.
- Depression.
- Abdominal distension is not always present, especially in dogs who have the majority of their stomach tucked up under the rib cage.
- Acute presentation
- Collapse.
- Dyspnea.
