Liver Histology Flashcards
Name 5 functions of the liver
Secretes products that aid digestion of macromolecules and absorption of nutrients in small intestine
* Bile is produced in liver and released into duodenum via the common bile duct
* Helps solubilizes, digest and absorb lipids
* Contains waste products – bilirubin and cholesterol
Receives and processes nutrients from small intestines
Synthesises and degrades plasma proteins
Detoxifies drugs and toxins
Stores glycogen and release glucose
Conversion of T4 to T3
Describe the structural organisation of the liver
Hepatocytes are arranged in lobules (that appear hexagonal in X section)
At (6) points around of lobule: portal triad:
* Hepatic artery
* Portal vein
* Bile duct
Centre of lobule: central vein
* Blood flows from hepatic artery & portal vein into central vein
Hepatocytes are in sinusoids between the portal triads and central vein
What is the CT like in liver?
- Very little
- Sinusoids are supported by collagen type III
Liver lobule structure:
What are the 3 zones in a liver lobule? [3]
Where are the 3 zones located in relation ot the portal triAd?
Differences in appearance between the 3 zones? [3]
Liver lobule structure:
All have different metabolic activities
What are the 3 zones in a liver lobule? [3]
* Zone 1: oxygenated blood
* Zone 2: medium oxygenated blood
* Zone 3: less oxygenated blood
Where are the 3 zones located in relation ot the portal triAd?
Zone 1: closest to portal triad: lighter purple
Zone 3: futhest to portal triad: deeper purple
What are the different functions of zone 1 c.f. zone 3 hepatocytes?
Zone 1 = oxidative/phase II reactions, gluconeogenesis and glycogen synthesis and, proteosynthesis and bile salt formation
Zone 3 = anaerobic/phase I reactions, glycogen stores (glycolysis), fat stores (lipolysis) and pigment store and glutamine synthesis
Label A-C
What is the cell structure like of bile ducts?
Simple squamous
Simple cuboidal
Simple columnar
Stratified squamous
Stratified columnar
What is the cell structure like of bile ducts?
Simple squamous
Simple cuboidal
Simple columnar
Stratified squamous
Stratified columnar
Which is bigger: portal vein or hepatic artery?
Which is bigger: portal vein or hepatic artery?
Label A-C
Describe how blood reaches the central vein
Blood from hepatic artery and portal vein mix and flow toward central vein through sinusoids
Sinusoids have:
continuous endothelium
discontinuous endothelium
fenestrated endothelium
Sinusoids have:
continuous endothelium
discontinuous endothelium
fenestrated endothelium
What is secreted at the apical surface of hepatocytes? [1]
Which way does the basolateral surface of the hepatocytes face in relation to the sinusoids? [1]
What is secreted at the apical surface of hepatocytes? [1]
Bile secretion into lumen on bile canaliculi
Which way does the basolateral surface of the hepatocytes face in relation to the sinusoids? [1]
Basolateral membrane faces the sinusoid: where materals absorbed / excreted
Label A-C
What is the name of the resident macrophages in the liver? [1]
Where exactly do they live? [1]
What is the name of the resident macrophages in the liver? [1]
Kupffer cells
Where exactly do they live? [1]
Lumen of sinusoids
Describe the passage of bile into gallbladder
- Hepatocytes secrete bile into canaliculi
- The canaliculi are defined by tight junctions between adjacent hepatocytes
- Bile flows through these narrow tubes towards the hepatic (bile) duct
- From the bile duct it flows into the biliary tree out of the liver to the gallbladder or intestines
Label A&B
Describe the structure of gallbladder cells
Characteristic features:
* Irregular shaped villi
* Lined with very tall columnar epithelial cells
* Smooth muscle in the wall contracts under influence of hormone cholecystokinin
* Expels bile into duodenum
Describe the structure of gallbladder cells
Characteristic features:
* Irregular shaped villi
* Lined with very tall columnar epithelial cells
* Smooth muscle in the wall contracts under influence of hormone cholecystokinin
* Expels bile into duodenum
Describe the histopathological changes that occur due to cirrhosis?
What effect does this have?
Parts of the liver are repeatedly destroyed and replaced with type 1 collagen and type 3 collagen from hepatic stellate cells at the expense of the hepatic architecture
This scarring disrupts the sinusoids and this results in the backup of blood in the portal vein and portal hypertension
Explain how alcoholism can induce steatosis?
Alcoholism can also induce steatosis because the metabolism of ethanol produces NADH which shifts the metabolism of hepatocytes toward lipid synthesis
- Hepatocyte swelling and necrosis
- If chronic then fibrosis
Describe the histopathological changes that occur from cholestasis and why they occur [2]
Cholestasis is a pathological accumulation of bile within the liver parenchyma
It results from blockage of bile ducts or defects in bile secretion by hepatocytes
In this image, note the presence of bile in the ducts and cytoplasm of cells
Which pathology is depicted here?
Cholecystitis
Cholestasis
Steatosis
Cirrhosis
Which pathology is depicted here?
Cholecystitis
Cholestasis
Steatosis
Cirrhosis
Which pathology is depicted here?
Cholecystitis
Cholestasis
Steatosis
Cirrhosis
Which pathology is depicted here?
Cholecystitis: chronic
Cholestasis
Steatosis
Cirrhosis
Which pathology is depicted here?
Cholecystitis
Cholestasis
Steatosis
Cirrhosis
Which pathology is depicted here?
Cholecystitis
Cholestasis
Steatosis
Cirrhosis
