Liver Flashcards
Where is the liver located?
URQ, beneath diaphragm and behind lower ribs
How much does the liver weigh?
1500 g (3 lbs, size of football) -aka LARGEST internal organ
What is the major function of the liver?
Excretion of waste products from the bloodstream by excretion into bile
-detoxification by splenic blood
What are the 3 basic functions of the liver?
1) Metabolic- processing of dietary AAs, carbs, lipids and vitamins; synthesis of plasma proteins; synthesis of bile
2) Secretory
3) Vascular
What is the function of the hepatic artery?
Provides 20-30% of O2-RICH blood supply to liver
-Liver is a vascular organ
What is the function of the portal vein?
Provides 70-80% of NUTRIENT-RICH (O2-poor) blood supply to liver
-Drains from the digestive tract via the splenic vein and superior mesentric vein
What are the lobes of the liver?
4 lobes: RT (largest lobe), LT, quadrate and caudate lobes
How is the liver connected to the diaphragm and abdominal walls?
5 ligaments: Falciform ligament, Teres ligament, Coronary ligament, RT and LT triangular ligaments
What is unique to the liver?
Only human organ with self-regeneration; only have to donate a small piece
What are Kuppfer cells?
Phagocytic cells of the liver that ingest toxins and waste products of metabolism
What are sinusoids?
Fenestrated vessels (porous), wider than capillaries; lined w/ endothelial cells
- Allow for mixing of O2-rich blood from hepatic artery and nutrient-rich blood from portal vein
- Do all the work
The liver has Kuppfer cells and ___ cells.
Fat storing
How do blood and bile flow to and from the liver?
In OPPOSITE directions
- Blood flow: deoxygenated blood from stomach or small intestine -> hepatic portal vein -> venules -> sinusoids -> central vein -> hepatic vein -> vena cava
- Bile flow: bile produced in hepatocytes -> secreted into canaliculi -> bile ductules -> common duct -> gallbladder -> bile duct -> small intestine
What is the liver role in nutrient storage?
Hepatocytes absorb and store excess nutrients in the blood
-Glucose (stored as glycogen), iron, retinol (vitamin A), calciferol (vitamin D)
How are erythrocytes broken down in liver?
Hemoglobin is absorbed by phagocytosis by Kuppfer cells in the liver; Hb split into:
1) Heme groups -> iron is removed from a heme leaving a substance called bilirubin (bile pigment)
2) Globins -> hydrolyzed to AAs and returned to blood
What happens if hemoglobin is not absorbed by Kuppfer cells?
Too much iron -> buildup causes toxicity of liver -> Hemochromotosis
What is the life span of a normal, healthy RBC?
120 days
What does glucagon do?
Raises blood sugar by stimulating the breakdown of glycogen
Where are plasma proteins synthesized?
In the rER of hepatocytes
What are the 3 main types of plasma proteins synthesized by the liver?
Albumin, globulin, fibrinogen
What happens if you have less synthesis of plasma proteins?
Hypoalbuminemia-> Third spacing of fluid (this happens in liver disease) -> Peripheral edema (poor quality of life, increased chance of infection because of tapping of fluid and peritonitis)
If less plasma proteins are synthesized in liver disease, how should a patient’s medication be altered?
Patient should be given a lower dose to avoid toxicity
-Medications are active when they are “free floating” through the blood, they are inactivated when they are bound to plasma proteins (less plasma proteins -> more free floating)
Where is cholesterol made?
In hepatocytes in the liver
What is cholesterol the precursor for?
Steroid hormones made by the testis, ovaries or adrenal gland (progestins, glucocortoids, androgens, estrogens, mineralocortoids); also Vitamin D
What is associated with decreased liver function?
Decreased adrenal function
What is cirrhosis?
Replacement of liver tissue with fibrosis (scar tissue) and regenerative nodules (lumps that occur due to attempted repair of damaged tissue)
-symptoms typically show up 20-30 years later
What are the most common causes of cirrhosis?
Alcoholism, hepatitis (especially B & C; C causes liver cancer), biliary (fatty liver disease)
What is the most common complication of cirrhosis?
Ascites- fluid retention in abdominal cavity (often caused by hypoalbuminemia)
What is hepatic encephalopathy?
AMS caused by buildup of toxins in blood (ammonia) that liver is unable to filter, can cause seizures and death
-aka organic brain syndrome (OBS)
What is alcohol dehydrogenase?
The enzyme used to breakdown alcohol; responsible for tolerance but does not change BAC
What bleeding problems are associated with cirrhosis?
1) Vascular problem: portal vein cannot dump blood into vena cava -> backs up into venous end -> surrounding veins swell -> varicose veins and esophageal varices
2) Hematologic: clotting factor
What are some PE findings consistent with liver dysfunction?
1) Hepatomegaly - enlarged liver
2) Ascites - needs about 1500 mL to be detected
3) Fetor hepaticus - musty breath odor from increased dimethyl sulfides
4) Jaundice
5) Muehrcke’s lines - paired horizontal bands separated by normal color in nails (due to hypoalbuminemia)
6) Terry’s nails - proximal 2/3 nail plate white, distal 1/3 read (due to hypoalbuminemia)
7) Clubbing - angle between nail plate and proximal nail fold >180 degrees
8) Dupuytren’s contacture - thickening and shortening of palmar fascia -> flexion deformities of fingers
What are spider angiomas?
Vascular lesions that blanche when you press them
-result due to an increase in estradiol (in 1/3 of patients with liver dysfunction)
What is the cause of palmar erythema?
Increased estrogen seen in liver dysfunction
What is a gynecomastia and what causes it?
Non-cancerous lesion caused by increase in estradiol
-seen in 2/3 of pts with liver dysfunction
What are other features of liver dysfunction?
- Spider angioma/spider nevi
- Palmar erythema
- Gynecomastia
- Hypogonadism
What is portal hypertension?
Increased hepatic vascular resistance (due to scarring and fibrosis/cirrhosis)
What are some effects of portal hypertension?
- Splenomegaly
- Esophageal varices
- Caput medusae
- Cruveilheir-Baumgarten murmur
What is a Cruveilheir-Baumgarten murmur?
Abdominal wall bruit and palpable thrill/venous hum heard in epigastric area, due to collateral collections formed between portal system and the remnant of the umbilical vein
-secondary to portal hypertension
