The Liver HL IB Bio Mrs. Whitman and Mr. Everhart.

The LiverHL 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=ammoniaurea

Storage of nutrients

• Carbs: glucoseglycogen• 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• 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 tissuecirrhosis• 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