The abdominal organs may be classified as solid organs, or hollow organs. The solid organs are the liver, pancreas, spleen, kidneys, and adrenal glands. The hollow organs of the abdomen are the stomach, intestines, gallbladder, bladder, and rectum. In the thoracic cavity the heart is a hollow, muscular organ.The number of organs in any organism depends on the definition used. By one widely adopted definition, 79 organs have been identified in the human body. Animals
Except for placozoans, multicellular animals including humans have a variety of organ systems. These specific systems are widely studied in human anatomy. The functions of these organ systems often share significant overlap. For instance, the nervous and endocrine system both operate via a shared organ, the hypothalamus. For this reason, the two systems are combined and studied as the neuroendocrine system. The same is true for the musculoskeletal system because of the relationship between the muscular and skeletal systems. Cardiovascular system: pumping and channeling blood to and from the body and lungs with heart, blood and blood vessels. Digestive system: digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, colon, rectum and anus. Endocrine system: communication within the body using hormones made by endocrine glands such as the hypothalamus, pituitary gland, pineal body or pineal gland, thyroid, parathyroids and adrenals, i.e., adrenal glands. Excretory system: kidneys, ureters, bladder and urethra involved in fluid balance, electrolyte balance and excretion of urine.
Liver biopsy
On microscopic examination of liver biopsy specimens, PBC is characterized by chronic, nonsuppurative inflammation, which surrounds and destroys interlobular and septal bile ducts. These histopathologic findings in primary biliary cholangitis include:
Inflammation of the bile ducts, characterized by intraepithelial lymphocytes
Periductal epithelioid granulomas. Proliferation of bile ductules
Fibrosis (scarring)The Ludwig and Scheuer scoring systems have historically been used to stratify four stages of PBC, with stage 4 indicating the presence of cirrhosis. In the new system of Nakanuma, the stage of disease is based on fibrosis, bile duct loss, and features of cholestasis, i.e. deposition of orcein-positive granules, whereas the grade of necroinflammatory activity is based on cholangitis and interface hepatitis. The accumulation of orcein-positive granules occurs evenly across the PBC liver, which means that staging using the Nakanuma system is more reliable regarding sampling variability. Liver biopsy for the diagnosis and staging of PBC lost favour after the evidence of a patchy distribution of the duct lesions and fibrosis across the organ. The widespread availability of noninvasive measures of fibrosis means that liver biopsy for staging of PBC is somewhat obsolete. Liver biopsy does, however, remain useful in certain settings. The main indications are to confirm the diagnosis of PBC when PBC-specific antibodies are absent and confirm a diagnosis of PBC with AIH features (i.e. overlap PBC-AIH). Liver biopsy is also useful to assess the relative contribution of each liver injury when a comorbid liver disease is present, such as non-alcoholic steatohepatitis.