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Rat liver | Rat pancreas | Rat gut |
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Size | Transverse diameter = 7.5–8 cm, superior-inferior diameter = 2.8–4.2 cm, anterior-posterior diameter = 2.2–2.5 cm. 5% of total body weight, mean weight = 13.6 g | Size | Weight = 804 mg | Size | The long tube measures up to 2 m in length |
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Location | Upper right portion of the abdomen, beneath the diaphragm and above the stomach. A small portion extends into the upper left quadrant | Location | In the cranial abdominal cavity, between the stomach and the small intestine | Location | From mouth to anus |
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Shape | 4 lobes: left, middle, right, and caudate | Organisation | Diffused, lobulated in appearance and divided into 3 parts: biliary, duodenal, and gastrosplenic | Oesophagus | Long tube from mouth to stomach, approx. 20 cm long |
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Organisation of hepatocytes | Lobular | Endocrine tissue | 2–3.5% of the pancreas. 5000 islets of Langerhans scattered within the organ | Composition | Stratified squamous epithelium |
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Composition | Hepatocytes, endothelial cells, bile duct epithelial cells, Kupffer cells | Beta cells | 65–80% of the islet. Production of insulin granules (207 nm) | Role | Transport food from mouth to stomach |
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Hepatocytes | 80.6% of total liver volume | Alpha cells | 15–20% of the islet. Production of glucagon granules (172 nm) | Stomach | Functions are comparable to the ZF intestinal bulb, approx. 6 cm long |
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Size | Polyhedral, 27 µm in diameter. Overlapping plate-like sheets (trabeculae) form the three-dimensional structure of the liver lobule | Other-cells | Delta-cells (3–10% of the islet) produce somatostatin. PP-cells (3–5% of the islet) produce pancreatic polypeptides | Composition | Enterocytes are the main cell types (90% of the villi surface) |
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Organelles | Nucleus (25% are binucleate), mitochondria, rER, sER, lysosomes, Golgi apparatus, peroxisomes, lipid droplets, free ribosomes, lipoproteins, glycogen, polyosomes | Vascular system | Rich vasculature (10% of the islet) | Role | Storage of food, start of enzymatic digestion |
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Biliary system | 0.2% of liver | Exocrine tissue | 95% of the pancreas | Small intestine | Functions are comparable to the midintestine, approx. 1–1.5 m long |
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Bile canaliculi | Presence of microvilli on the surface. Diameter = 1.5 µm | Acinar cell | Polyhedral, 10 µm in diameter, surrounding a central acinar duct. | Composition | Divided into 3 parts: duodenum, jejunum, and ileum. Enterocytes are the main cell types |
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Bile ducts | Intrahepatic, interlobular, and extrahepatic bile ducts | Organelles | Zymogen granules (500–800 nm), nucleus, ER, mitochondria | Role | Absorption of nutrients |
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Vascular system | 19.2% of liver volume | Pancreatic system | Anterior pancreatic duct (main duct) occupies 50–60% of the pancreas. Draining the pancreatic juice to the stomach and small intestine | Large intestine | Functions are comparable to the posterior intestine, approx. 22–26 cm long |
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Endothelial cells | Fenestrated, average diameter = 6.5 µm | | | Composition | Enterocytes |
| | Role | Absorption of water and left over digested nutrients |
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