Normal Histology | Histology Image Gallery
Liver
Mon 11 May 2009 10:48:24 PM EDTThe liver is fairly complex and its histology is directly related to its anatomy and function. Here are the basics though. The liver is divided into hexagons, lobules, through sheets of connective tissue which can been seen easily on a reticulin stain. There are portal triads at the six points of the hexagon and a central vein in the middle. The liver cells are termed hepatocytes. Hepatocytes are polygonal in shape and are joined with one another in anastomosing plates, with borders facing sinusoids or other hepatocytes.
Lung
Mon 11 May 2009 10:51:52 PM EDTThe lung, and the respiratory system is divided into the conducting portion and the respiratory portion, which allows for the exchange of gases. The conducting portion consists of thick tubes of tissue which clean and humidify air through a pseudostratified ciliated columnar epithelium with goblet cells on top of a connective tissue lamina propria. This gradually changing as you go closer to the alveoli to cuboidal cells and then squamous-like cells with loss of goblet cells, then ciliated cells. The connective tissue cartilage, smooth muscle cells and seromucous cells disappear, with only pneumocytes left at the ends forming the alveolar sacs and ducts.
Lymph Node
Mon 11 May 2009 10:52:38 PM EDTLymph nodes are the lymphoid organs which allow for the interaction of immune cells with antigen within lymph, that has been drained from the tissues. Lymph nodes consist of an architecture of connective tissue forming a stable framework, where histiocytes and antigen presenting cells reside and stimulate B cells into germinal centers and lymphoid follicles with help from T cells. Lymph nodes are also the site of lymphomas such as Hodgkins.
Pancreas
Mon 11 May 2009 10:54:19 PM EDTThe pancreas is both an endocrine and exocrine organ. Therefore, it has basically two cell populations. There are lightly staining cell clusters termed the islets of Langerhans, which make the hormones insulin and glucagon. The darker staining cells, arranged in a glandular architecture are the exocrine pancreas. These acini connect to ducts and then to larger ducts that empty into the gastrointestinal tract and aid in digestion of food.
Parathyroid Gland
Mon 11 May 2009 10:55:55 PM EDTHumans most often have four parathyroid glands, but variations are common. The parathyroid gland consists of two types of cells, the parathyroid chief cells, which are dark staining, smaller in size and more abundant. The chief cells make parathyroid hormone, PTH. The other cells, the lighter staining cells, which are larger but less abundant than the chief cells, are the oxyphil cells which do not have a known function.
Placenta
Mon 11 May 2009 10:56:52 PM EDTThe placenta is a complex but interesting organ, with a fetal side and a maternal side. The fetal side consists of villi surrounded by trophoblast and a connective tissue core with vessels. The surrounding trophoblast has a outer syncitiotrophoblast and an inner layer of cytotrophoblast. The core consists of mesenchymal cells. The maternal side consists of a decidual reaction with fibrin deposition. Decidualization is the process of change in the endometrial glands when exposed to progesterone, as in the menstrual cycle. The tissue becomes plump red and thick.
