Download Digestive system

Hepatic Pathology and Respiratory
System
Topics in Human Pathophysiology Fall 2011
Gilead
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 Liver
Part 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 Hepatitis
Hepatitis A
(HAV)
Hepatitis B (HBV)
Hepatitis C (HCV)
Etiology
Causes mild
acute illnesshepatocyte
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-oral
primarily 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 vaccine
From 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 liver
See labtestsonline for more information
CT Scan of the Liver
Normal liver
Nodular cirrhotic liver with ascites
www.integris-health.com
17
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
Respiratory Functions
 Gas exchange
 Protection
 Speech
 Compression of abdomen and spine
stiffening
 Acid-Base balance
Figure 10.8

Respiratory Interface
 Alveolar wall
 Capillary wall
 Surfactant
 Gas Exchange occurs by diffusion