GHM L6 Flashcards
State the functions of the liver
-Bile production
-Processes nutrient-rich blood in hepatic portal system
-Detoxifies the blood
-Stores glycogen
-Produces foetal erythrocytes
-Produces amino acids, lipids and more complicated carbohydrates
-produces proteins (blood-clotting factors
Describe the position of the liver
Immediately inferior to diaphragm
Right side of midline
How is the liver protcected?
RIB CAGE
ANATOMY OF THE LIVER
RIGHT AND LEFT HEPATIC DUCTS OF LIVER
CYSTIC DUCT
BARE AREA (touches diaghragm, not covered by visceral peritoneum)
-Sternum
-Nipple
-LIVER
RIGHT LOBE OF LIVER - VISBLE FROM ALL ASPECTS
Gallbladder
Round Ligament - remenants of foetal umbilical vein
Left Lobe of liver
Falciform ligament - mesentry - separates both lobes, suspends liver from diaphargm and anterioir body wall
PORTA HAPATIS - contains hepatic artery (left) and heparitc portal vein (right) from lesser omentum
QUADRATE LOBE OF LIVER
CAUDATE LOBE OF LIVER
Describe the segments of the liver
8 segments, clockwise from the caudate lobe
Each section has its own branches of portal vein, hepatic artery, bile duct
Describe the microscopic anatomy of the liver
Lobule
Central vein
Connective tissue septum
Describe the liver lobule
WHAT TO RECOGNISE ON DIAGRAM:
- Hepatic macrophages
- Sinusoids
- Hepatocyte plates
- Bile canaliculi
- Bile duct
- Fenestrated lining of sinusoids
- PORTAL TRIAD - portal venule, portal arteriole, bile duct
Descibr the structure and function of the hepatic macrophages
-Stellate, star shaped
-Remove bacteria and damaged erythrocytes from blood
-In sinusoids (sinusoid wall)
RECOGNSISE ON DIAGRAM
State the function of the hepatic artery
Provides oxygen rich blood to liver
State the function of hepatic portal vein
Supplies nutrient rich blood to the liver
Histology of Liver Lobule
-
State functions of hepatocytes
Produce bile
Storage of fat-soluble vitamins (VIT A)
Convert ammonia to urea
Protein synthesis
Glycogen synthesis
SECRETE GROWTH FACTORS IF LIVER IS INJURED
State functions of the gallbladder
STORAGE OF BILE, CONCENTRATE THE BILE
MUCOSA FOLDS OF GALLBLADDER EXPAND +TO FILL
THIS MUCOSA THEN CONTRACTS TO EXPEL THE CONTENTS
State which type of epithelium is present in the gallbladder
Simple columnar epithelium
Describe the structure of the gallbladder
HAS A BRUSH BORDER OF MICROVILLI
HAS A LAMINA PROPRIA
HAS A MUSCULAR LAYER
HAS A SEROSA
Describe how the structure of the gallbladder is similar to that of the intestinal absoptive cells. Also state the differences
SIMPLE COLUMNAR EPITHELIUM
BRUSH BORDER OF MICROVILLI
HAS LAMINA PROPRIA
HAS A MUSCULAR LAYER
HAS A SEROSA
GALL BLADDER DOES NOT HAVE MUSCULARIS MUCOSAE
Describe the compoosition of bile
- BILE SALTS (e.g. cholic acid)
This emulsifies fats, RECYCLED via enterohepatic circulation - BILE PIGMENTS - bilirubin
Product of heamoglobin breakdown
Metabolised by gut flora
bilirubin is broken down into sterocobilin which gives faeces its brown colour - Cholestrol
excess cholestrol is excreted in bile
this cholestrol is form:
-triglycerides
-phospholipids
-electrolytes
Describe the enterohaptic circulation of bile acids
Bile acids synthesised, secreted into bile, stored in gallbladder
Some circulated from CHOLANGIOCYTES (epithelial cells of bile duct) back into liver
Describe enterohepatic circulation after a meal
After meal, bile acids excreted to intestines
Some passively absorbed in upper intestines
Most reasbrobed in terminal ileum through sodium dependant salt transporter
(in epithelium/enterocytes of ileum)
where it is transported to blood then back to liver via hepatic portal system
Process happens many times a day
How much bile is recycled and what happens to the rest?
MOSTLY recirculated back to liver
OR
very little lost in FAECEL EXCRETION
very little in SYSTEMIC CIRCULATION, (WHICH IS CLEARED IN URINE)
Describe the mechanisms promoting secretion and release
- Chyme enters duodenum
- Causes release of CCK + secretin from duodenal enteroendocrine cells
- CCK + secretins enter blood stream
- CCK stimulates secretion of enzyme-rich pancreatic juice
- Secretin stimulates secretion of bicarbonate rich pancreatic juice
- Bile salts + secretin transported to in bloodtsream to stimulate liver to produce bile more rapidly
- CCK causes gallbladder to contract, hepatopanreatic sphincter to relax, bile enters duodenum
- During celiac + gastric phases, vagal nerve stimulation causes weak contractions of bladder
State where cholecystokinin is produced and where it is found
- Synthesised by enteroendocrine cells
- Mostly found in DUODENUM, JEJUNUM
State two issues with the secretion of cholecystokinin
- Anxiogenic (causes anxiety)
- Hallucionogenic (causes hallucinations)
State hormones involved in hunger and satiety
CCK
GHRELIN
GLUCAGON
LEPTIN
INSULIN
ADRENALINE
Which nerve fibres are involved in hunger and satiety?
VAGAL NERVE FIBRES
Describe factors affecting hunger and satiety
Blood glucose. When high, there will be a decrease in eating. But, when high, dopamine is also high, therefore, people overeat for pleasure
Blood amino acids - when high, decrease eating
Blood fatty acids, when high, decrease eating / HUNGER
Why do people tend to overeat despite them being “full” ?
When full, high blood glucose levels
Although this decreases hunger, which should decrease eating, increase in blood glucose, increases dopamine (positve reinforcement, pleasure), they continue to eat more to seek pleasure
State 4 patholgies related to the liver
- Hepatitis
- Alcoholic Liver Disase
- Cirrhosis
- Portal Hypertension
State the cause, symptoms and treatment of gallstones
Cause:
Excess cholestrol, too less bile salts
This leads to crystallisation
Symptoms
MOST PEOPLE SYMPTOM FREE
PAIN WHILE GALLBLADDER CONTRACTS
BLOCKAGE OF BILE DUCT - LEADS TO JAUNDICE
Treatment
Removal, dissolution, sonication
State the cause and symptoms of Hepatitis
Hepatitis - inflammation of liver
Cause:
1.Viruses known as HepA - HepF lead to presence of inflammatory cells in liver
- Damage caused by drugs, alcohol, autoimmune disease
(PRIMARY) symptoms
-flue-like
-jaundice
-appetite loss
-swelling of liver
-swelling of spleen
-Can be symptom free
can lead to
-CIRRHOSIS
-PORTAL HYPERTENSTION
State the two types of hepatitis
Acute (Hep A)
Chronic (Hep B)
State the risk factors of alcoholic liver disease
Gender: 2x more likely for women
Drinking without food (alcohol)
Diet: Low Vit A + E
Genes - hereditery
Describe how alcoholic liver disease occurs
- Long term excessive alcohol consumption
- Excessive alcohol leads to accumulation of fatty acids in liver cells (FATTY LIVER)
- Also leads to TNF-a and IL (inflammatory mediators) being released in response to the liver damage caused by alcohol. This triggers inflammation, damages hepatocytes + other liver cells. Liver cells undergo apoptosis. LEADS TO ALCOHOLIC HEPATITIS
- Cirrhosis of liver: Inflammation + liver damage = cirrhosis. Formation of scar tissue (FIBROSIS), replaces healthy rissue, disrupts liver function (CIRRHOSIS IS SIGN OF END STAGE ALCOHOLIC LIVER DISEASE) = LIVER F A I L U R E
State the causes, symptoms of liver cirrhosis
Formation of scar tissue (fibrous) in liver
How does cirrhosis lead to loss of liver function?
- In cirrhosis, normal healthy liver tissue replaced by excessive connective tissue (scar tissue). Scar tissue regenerates at a faster rate than liver tissue (hepatocytes)
Hepatocytes are funcional cells of liver
As scar tissue continues to accumulate, disrupts organisation of cells. Affects blood flow, exchange of nutrients and waste products.
State the causes, symptoms of portal hypertenstion
Inrease in BP in portal venous system
Causes:
- Liver cirrhosis: formation of lots of scar tissue (fibrosis). Disrupts blood flow to liver, increases pressure in portal venous system
- Due to increased pressure, (due to above), smaller veins in portal venous system ruptured
- THROMBOSIS - BLOOD CLOTS within portal venous system
SYMPTOMS:
- Vomiting blood (due to bleeding in upper GI tract
- Oesophagal verices - enlarged fragile blood vessels, can rupture
- Caput Medusae - engorged veins on abdomen (due to increased pressure in portal venous system)
- Ascites: Accumulation of fluid in perioneal cavity
Give treatment options for liver pathologies
PREVENTION of viral infection through vaccination
Liver dialysis - short-term, not fully effective
Liver transplants - most effective
What is the issue with liver transplants as a treatment for liver pathologies? Give an alternative
Organs are scarce
Tissue engineering
