Histology of Liver, Pancreas and Salivary Glands

Pancreas

• Located behind the stomach in the abdomen
• Plays a key role in digestion and blood sugar regulation
• Consists of three main histological layers: exocrine, endocrine, and connective tissue
• Exocrine layer contains acinar cells that produce digestive enzymes such as amylase, lipase, and proteases
• Enzymes are released into small ducts, which eventually merge into the main pancreatic duct
• Endocrine layer contains cells called islets of Langerhans, including alpha cells (secreting glucagon), beta cells (secreting insulin), and delta cells (secreting somatostatin)
• Connective tissue layer surrounds and supports the pancreatic lobules, consisting of fibrous tissue and blood vessels that supply nutrients and oxygen to the pancreas

Salivary Glands

• Play an important role in digestion, helping to moisten food
• Saliva contains an enzyme called amylase, which breaks down starches into sugars, and lingual lipase, which breaks down fats
• Consist of three types: Parotid, sublingual, and submandibular glands
• Histology: composed of glandular secretory tissue (parenchyma) and supporting connective tissue (stroma)
• Parenchyma consists of secretory acini, intercalated ducts, and striated ducts
• Ducts are recognizable by their simple cuboidal epithelium, with larger ducts having simple columnar or stratified cuboidal epithelium

Liver

• Located in the upper right-hand portion of the abdominal cavity, protected by the ribcage
• Reddish-brown in color, with a shape generally like a cone or wedge
• Divided into two conventional lobes: right lobe and left lobe
• Histology: composed of hexagon-shaped lobules
• Lobule consists of connective tissue, hepatocytes, and blood vessels
• Blood vessels include hepatic artery branches, portal veins, bile ducts, and central vein
• Liver capillary (sinusoids) are larger than normal capillaries, with irregular shapes and gaps in their walls, allowing for cell transport