Download The Liver - The Practical Educator

The Liver
HL IB Bio Mrs. Whitman and Mr. Everhart
Circulation of Blood
Sinusoids=-large lumen
Lobule: Sinusoids
Kupffer=phagocytes
Nutrient Storage
• Homeostasis
• Sugar+salt=osmolarity (osmolues/ liter)
• Extra amino acids
• No matter meal, liver maintains and regulates nutrients
• Ex: sugar 90mg/100mL
• Extra glucose=glycogen in hepatocytes; if in need turn into glucose
Nutrient Storage
• Ex: extra amino acids=ammoniaurea
Storage of nutrients
• Carbs: glucoseglycogen
• Controlled by pancreatic hormones (insulin and glucagon)
• Iron: component of hemoglobin
• Liver breaks down dead RBC and stores Fe in ferritin
• Vit A: vision: rhodopsin (low light); rods in retina
• Night blindness
Storage of Nutrients cont
• Vit D: uptakes Ca; prevents rickets
• B12: helps nerve and blood cells
• Prevents anemia
Liver synthesizes plasma proteins & cholesterol
• Plasma proteins
• Albumin- osmotic pressure (tendency to uptake water)
• Fibrinogen- precursor for fibrin (clots blood)
Detox
• Hepatocytes have enzymes that break down toxins
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Alcohol
Preservatives
Herbicides
Nicotine
Alcohol Abuse
• Alcohol brought in via hepatic portal vein, converted by hepatocytes,
unconverted brought back through sinusoids via hepatic artery
Alcohol Abuse
• Healthy cells replaced by fibrous scar tissue
cirrhosis
• Fat accumulates
• Inflammation= alcoholic hepatitis
• Liver regerates
Erythrocyte and hemoglobin break down
• RBS rupture after 120 days
• Kupffer cells break down hemoglobin into globin and heme
• Globin is broken down into amino acids and returned into the blood
to later be used in protein synthesis
• Heme broken down into Iron and bilirubin (bile pigment)
• Iron is either stored or sent to bone marrow to contribute to new RBC
• Bilirubin is absorbed by hepatocytes and used to synthesize bile