Hepatic Pathology and Respiratory SystemTopics in Human Pathophysiology Fall 2011Gilead Drug Safety and Public Health
Outline Hepatic Pathophysiology
Digestive System Overview Placement and role of liver Liver microstructure Pathologies of liver
Respiratory Structure and Function
Digestive system
The LiverPart of digestive system
Located in upper right abdominal quadrant
Is served by two blood vessels: the hepatic portal vein, the hepatic artery
Has one duct that carries bile away from it to the gall bladder for storage
Composed of lobules that contain hepatocytes
Blood moves easily from the external vessels, in porous capillaries past the hepatocytes to a central vein
Hepatocytes do the work of the liver
Figure 14.11
Hepatic Portal System
Liver Functions
Secretes bile – which emulsifies fats within small intestine
Metabolizes bilirubin - a breakdown product of hemoglobin
Produces albumin, and clotting factors
Metabolizes fats, proteins, carbohydrates, stores glycogen, makes HDLs and LDLs
Inactivates many biologically active chemicals including alcohol, medicinal and recreational drugs, hormones, poisons
Stores fat soluble vitamins and iron
Converts ammonia (NH3) into soluble urea to be excreted by kidneys
Hepatitis• Inflammation of the liver• Causes include:
• Viruses and other pathogens
• Drug and alcohol toxicity
• Environmental toxins• Obesity, autoimmune
disorders
Viral HepatitisHepatitis A (HAV)
Hepatitis B (HBV) Hepatitis C (HCV)
Etiology Causes mild acute illness- hepatocyte injury
Causes acute illness and chronic liver disease, can lead to liver cancer
May cause acute illness, acts long term leading to chronic liver disease and risk of liver cancer
Mode of transmission
Fecal-oralprimarily in children, young adults
Contact with infected body fluids – blood, semen; contaminated needles, mother to newborn
Contact with infected blood, mostly through contaminated needles
Vaccination Hep A vaccine Hep B vaccine No vaccineFrom http://www.cdc.gov/hepatitis/index.htm
Figure 9.20
Reverse transcriptase required
Pathophysiology of Hepatitis Destruction of hepatocytes (necrosis) by
inflammation Altered blood flow through and to liver Edema – both peripherally and in portal vessel area Blockage of bile ducts leading to reduced bile in
small intestine and problems with fat absorption Reduction of ability to make blood proteins including
albumin, clotting factors, complement Buildup of blood toxins including urea and ammonia
Symptoms of Hepatic Damage Jaundice Dark amber colored urine Nausea/vomiting Abdominal pain - R upper
quad Fatigue Also- ascites, hepatic
encephalopathy, coma, death
Cirrhosis Long term
result of liver damage
Liver Tests – Liver Panel AST– liver enzyme, elevated with damage to cells ALT - liver enzyme, elevated with damage to cells ALP – enzyme related to bile ducts, levels elevate
if there is a blockage total bilirubin (blood)– may be elevated with liver
damage or excessive RBC destruction Albumin (blood) – checks on synthetic ability of
liver cells prothrombin time - decreased synthesis of
clotting factors by liverSee labtestsonline for more information
CT Scan of the Liver
17
Nodular cirrhotic liver with ascitesNormal liver
www.integris-health.com
Drug Induced Hepatotoxicity More than 900 drugs, toxins
and herbs cause drug induced hepatotoxicity,
20-40% of all fulminant liver failure cases are caused by drug induced hepatotoxicity
It is the most common reason a drug is withdrawn from approval
Damage to liver can be hepatocellular or cholestatic
Drug-Induced Hepatotoxicity from http://www.emedicine.com/Med/topic3718.htm
Figure 10.1 Respiratory System
Gas exchange Protection Speech Compression of abdomen and spine
stiffening Acid-Base balance
Respiratory Functions
Figure 10.8
Respiratory Interface
Alveolar wall
Capillary wall
Surfactant
Gas Exchange occurs by diffusion