Anatomy Flashcards
1
Q
Describe the structure of the intrahepatic Bile ducts.
A
- The ductules (smaller bile ducts) have a thinner wall made of cuboidal epithelium
- Larger bile ducts are made of a single layer of columnar epithelium with underlying flexible connective tissue
2
Q
Describe the Biliary Tree
A
- Segments of the left liver form the left hepatic duct
- Sectoral ducts of the right liver join to form the right hepatic duct
- Left and Right leave through the porta hepatis and join to for the Common hepatic duct
- This is joined by this Cystic duct to form the Common bile duct
- the Pancreatic duct joins it forming the ampulla of Vater
- This drains into the Duodenum through the Sphincter of Oddi
3
Q
Describe the structure of the Extrahepatic duct
A
- the wall has a dense fibrous connective tissue to contain a larger volume of bile
- smooth muscle cells to propel bile along
- lumen remains highly columnar epithelium
- Lies within the lesser omentum close to the free edge
4
Q
Descrube the blood supply of the extrahepatic bile duct
A
- supplied by the cystic arteries (from the coeliac in the foregut)
- drains into the Portal vein
5
Q
Describe the anatomical placement of the Portal Triad ( Bile Duct, Portal Vein, Hepatic Artery).
A
- The Bile Duct is right of the Hepatic Artery
- The Hepatic Artery and Bile Duct are anterior to the Portal Vein
6
Q
Describe the anatomical position of the Gall Bladder
A
- found on the visceral surface of right liver lobe
- it’s at the inferior border of the liver anteriorly and the duodenum posteriorly
- It’s held by the same layer of visceral peritoneum as the liver
7
Q
Describe the anatomy of the Gall bladder
A
- Divided into the Fundus, Body and Neck
8
Q
What is the function of the gall bladder?
A
- store and concentrate bile salt
- selectively absorb bile salts
- to excrete cholesterol
- to excrete mucous
9
Q
Describe the mechanism of the Gall bladder emptying
A
- if fatty foods are detected in the duodenum, ( Cholecystokinin) CCK is released
- CCK release triggers the gallbladder to contract and bile flows down the biliary tree
- Sphincter of Oddi relaxes and bile enters the duodenum
10
Q
Describe the anatomy of the pancreas
A
- 12-15 cm long, 3 cm wide
- head, body, tail
- exocrine secretions are collected into small ducts then form one main duct called Wirsung
- the duct of Santorini which drains directly into the duodenum
11
Q
Describe the anatomical position of the Pancrease.
A
- found posteriorly to the stomach
- Head and body located in the Epigastrium
- the tail is in the left hypochondriac region closer to the spleen
- the head of the pancreas is encircled by the duodenum
12
Q
Descibe the function and histology of the Pancreas
A
- acts as an exocrine and endocrine gland
Exocrine
- Acini (cluster cells) make up 98-99% of total cell population: they excrete digestive enzymes
- they are pyramidal cells
Endocrine
- Centroacinar cells, islets of Langerhans; secretes hormones, insulin
- they are cuboidal cells
13
Q
Give the VAN of the Pancreas
A
- Arteries: mostly the splenic artery from the Celiac trunk, also the gastroduodenal and pancreaticoduodenal (which anastomosis with the superior mesenteric artery)
- Veins: Pancreatic veins, draining into the portal vein
- Nerves: sympathetic via Coeliac ganglia and parasympathetic via Vagus nerve
14
Q
What disease process occurs to the pancreas and what causes them?
A
Inflammation
- gallstones
- heavy alcohol intake
- cystic fibrosis
- high levels of calcium or blood fats
Pancreatic Cancer
- obstructive jaundice (gallstones)
- heavy alcohol intake
- smoking
- genetics
15
Q
Describe the anatomical position of the spleen
A
- located in the left hypochondria region
- lyes under ribs 9, 10 and 11
16
Q
Describe the anatomy of the Spleen
A
- Surrounded by Connective tissue
- inside contains parenchyma divided into two sections
Red pulp: blood-filled venous sinuses
White pulp: a greater proportion of lymphatic tissue
17
Q
What is the main role of the Spleen?
A
- immunity
- removal of old blood cells by macrophages
- storage of platelets
- during the fetal stage: produces blood cells
18
Q
What are the main functions of the liver?
A
- detoxification
- protein synthesis
- production of bile
- glycogen storage
19
Q
Describe the location of the liver
A
- below the diaphragm
- right of the stomach
- above the colon
- overlies the gallbladder
- mostly in the right hypochondrium and epigastrium, does extend into the left hypochondrium
20
Q
What can be seen on the posterior view of the liver?
A
21
Q
What are the peritoneal folds associated with the liver and what are their functions?
A
- Falciform ligament: links diaphragm to the upper surface of the liver. ligamentum trees (round ligament) at eh lower end
- Round ligament: obliterated left umbilical vein, extends to the umbilicus
- Coronary ligament: links the diaphragm to the liver
- Lesser omentum: links the liver to the stomach
22
Q
Where does the lesser omentum extend to and what does it enclose?
A
- from the lesser curvature of the stomach to the porta hepatis
Encloses
- hepatic artery
- portal vein
- bile duct
- lymph vessels
- encloses the fastic arteries and veins near the stoamach
23
Q
What is the blood supply to organs in the foregut, midgut and hindgut?
A
- Foregut: Coeliac artery/ trunk
- Midgut: superior mesenteric artery
- Hindgut: inferior mesenteric artery
24
Q
What is the blood supply of the liver?
A
- the hepatic artery originating from the coeliac artery (foregut organ)
- the portal vein: formed by the joining of the sup mesenteric and splenic veins
25
Where does the coeliac artery exit from the aorta, what are the main branches and the organs it supplies?
- exits the aorta at T12/L1
- Main branches: Left gastric, Splenic, Hepatic
- also supplies: duodenum and the pancreas
26
What are the function of hepatocytes?
* Synthesis and release plasma proteins into blood, e.g. albumin clotting factors
* Deaminates amino acids, creating ammonia (this is then converted into urea in order to be safe)
* Converting bilirubin to bile pigment
* Production of bile salts, to emulsify fats
27
Describe the division of the liver into segments
- Lobes divided into Couinauds, according to how the hepatic artery and portal vein subdivide them
- branches of hepatic artery and portal vein carry blood into sinusoids
- Each lobe of liver contains several lobules which are hexagon-shaped
- these lobules contain hepatocytes which secrete bile
- each lobule has a portal triad at each corner
28
Describe the venous drainage of the liver
- mixed portal and hepatic blood in sinusoids pass through the hepatocytes into the central vein
- the central vein is at the centre of a hepatic lobule
- several central veins then drain into the interlobular (sublobular) vein
- sublobular veins drain into hepatic veins
- hepatic veins drain into the inferior vena cava
29
What is the Hepatic portal system?
- blood draining from the GI tract towards the liver
- anything that is absorbed from the GI has to pass through the liver before reaching the heart
30
What is portal-systemic anastomosis?
- the systemic anastomosis is having some branches between the portal and systemic systems
- these are **portocaval** anastomosis: this allows blood to bypass the liver to get to the heart
- prevents _portal hypertension_ if the portal vein becomes blocked or passage via the liver meers resistance
31
Give some examples of portal-systemic anastomosis
* Abdominal part of oesophagus – _left gastric tributaries_ with oesophageal branches azygos
* Anal canal – _superior rectal_ anastomoses with middle and inferior rectal
* Umbilicus – _paraumbilical veins_ with epigastric veins
* Veins of _colon, duodenum, pancreas, liver_ with renal, lumbar and phrenic
(underlined is portal system)
32
What are the presenting signs of portal hypertension? And how can it be treated?
- Varicoses
- Caput medusa
Transjugular intrahepatic portosystemic shunting (TIPS)
33
How would the liver experience trauma and whats the impact?
- if ribs are fractured/ a penetrating wounds
- the liver is highly vascularized leads to severe haemorrhage
- portions can be removed due to the segmental nature of the liver: this can be done if there is metastatic spread, cirrhosis and in case of liver bipsies
