Anatomy Misc.

Question 1

What does the ventral mesentery give rise to?

Answer 1

Lesser omentum Falciform ligament *As the liver grows rapidly it divides the mesentery

Question 2

What does the dorsal mesentery give rise to?

Answer 2

Dorsal mesocolon Greater omentum Mesentery of the small intestine *Acts as a pathway for vessels to travel to the gut

Question 3

Describe the embryological development of the pancreas

Answer 3

The pancreas is a foregut derived structure, formed from embryonic endoderm. The pancreas is formed from a ventral and a dorsal bud. Ventral bud –> Ucinate process Dorsal bud –> Head, neck, body and tail

Question 4

Describe the formation of the portal vein

Answer 4

The portal vein is formed from the union of the splenic and SMV

Question 5

Describe the hepatic blood supply

Answer 5

CT, common hepatic artery, hepatic artery proper, left and right hepatic arteries

Question 6

State the exocrine cells of the pancreas

Answer 6

Duct cells: Secrete bicarbonate ions Acinar cells: Secrete digestive enzymes e.g. proteases Collectively secrete pancreatic juice

Question 7

Outline the mechanism of portal hypertension and describe the possible consequences

Answer 7

Portal hypertension results from increased pressure within the portal system, causing porto-systemic hypertension. Portal hypertension is resultant of ‘blocked’ flow through the liver - commonly caused by cirrhosis. Consequences: Splenomegaly, oesophageal varices, caput medusa

Question 8

Name the retroperitoneal structures of the pancreas

Answer 8

Suprarenal gland Aorta/IVC Duodenum (except the first part - duodenal cap) Pancreas (except tail) Urethras Colon (ascending and descending) Kidneys (o)Esophagus Rectum

Question 9

What is hepatic encephalopathy?

Answer 9

A decline in brain function that is associated with acute or chronic hepatic insufficiency. As liver function decreases removal of toxins is decreased. This leads to a build-up of toxins within the bloodstream which may cause brain damage. Symptoms include mood and sleep disturbances

Question 10

Palmar erythema indicates….

Answer 10

Indicative of hepatic failure

Question 11

Where does the cystic artery arise from?

Answer 11

From the hepatic artery proper, from the CT

Question 12

Where does the portal vein form?

Answer 12

Posterior to the neck of the pancreas, around vertebral level L2

Question 13

Describe the venous drainage of the liver

Answer 13

The anterior, middle and posterior hepatic veins drain into the IVC

Question 14

Describe the portal venous system

Answer 14

The portal venous system is a vascular system with a capillary bed at either end. Blood from the abdominal region passes through the portal system, allowing cleansing of the blood as it passes through the hepatic capillary bed before returning to the systemic circulation.

Question 15

Describe the bare area of the liver

Answer 15

The bare area is found on the posterior aspect of the liver. The bare area is a space between the anterior and posterior coronary ligaments and it the point of contact between the liver and the diaphragm.

Question 16

What symptom may be related to pancreatic cancer?

Answer 16

Jaundice. The CBD passes posterior to the pancreas. A mass of the pancreas may obstruct the duct and cause jaundice (as bilirubin passes into the blood stream)

Question 17

Outline the autonomic supply of the abdominal viscera

Answer 17

Sympathetic and parasympathetic Foregut: Greater Splanchnics T1-T9, Vagus Midgut: Lesser T10-T11 and Least T12 Splanchnics, Vagus Hindgut: Lumbar Splanchnics L1-L3, Pelvic Splanchnics S2-S4

Question 18

Outline the pattern of pain within the abdominal viscera

Answer 18

Irritation of visceral peritoneum: Sensitive to stretch. Pain is felt at the area of the quadrant which relates to embryological origin (epigastric, umbilicus or pubic). Can also be referred, e.g. appendicitis. 2nd order neuron signalling leads to referral to skin, e.g. T10 Irritation of parietal peritoneum: Sensitive to pain. Pain is localised to the organ location

Question 19

Describe the defecation reflex

Answer 19

As faeces enter the anal canal stretch receptors detect the mass and signal for signal for relaxation of the internal anal sphincter. The internal anal sphincter, smooth muscle under involuntary control (inferior hypogastric plexus), relaxes. The external anal sphincter, skeletal muscle under voluntary control, may open if convenient. If not convenient the sphincter will contract, depressing the reflex. The faeces returns back to the colon until the next mass movement of the bowel.

Question 20

Outline the areas drained by the left and right hepatic ducts

Answer 20

Left: Drains the left, caudate and quadrate lobes

Right: Drains the right lobe

Question 21

Describe the supra and infra colic compartments. How are they connected?

Answer 21

Supracolic compartment is a division of the greater sac, above the transverse mesocolon. Infracolic is below this land mark.

The 2 compartments are connected via the paracolic gutters.

☆ Subphrenic recesses: Potential spaces between the diaphragm and the liver. Pus may accumulate here, causing a subphrenic abscess to form. Spread to this area can occur via the paracolic gutters. May also spread to the hepatorenal recess.

Question 22

Describe the importance of the hepatorenal recess

Answer 22

Fluid may accumulate within this potential space in conditions such as ascites - via the right colic gutter

Question 23

Describe the significance of the pelvic pain line

Answer 23

• Structures above the inferior peritoneum convery visceral pain via sympathetic splanchnic nerves
• Structures below the interior peritoneum conver visceral pain via parasympathetics pelvic splanchnic nerves