On the welcome page of the dictionary, three major sections are shown: Normal tissues, Cancer and Cell structure. Below the image of each section are links to introductory texts for i) normal tissue histology, ii) hallmarks of cancer, and iii) cell structure overview. For the cancer-section there is also a link to current cancer statistics (incidence, survival, etc) for Sweden and the rest of the world. Within each section there are direct links to histology descriptions of different tissue types and tumor forms as well as descriptions of cell structures.
For the 'Tissue & cell types' and 'Tumor' sections, tissue-slides stained with hematoxylin and eosin (HE) are shown at three different levels of magnification. On the top level, an overview of the whole tissue-sample is shown with boxes in black indicating where zoomed-in representative parts of the tissue are available for viewing. Clicking on these boxes will zoom in on that part to show tissue structures, cells and features in greater detail. Throughout these sections, arrows indicate relevant tissue structures, cell-types and other features.
For the 'Cell structure' section, immunofluorescent images of formaldehyde-fixed cell lines are shown. The various cell structures that are demonstrated are always shown in the green channel using an antibody found in the Human Protein Atlas. The antibody name is linked to the subcellular location summary page of the target gene. The other channels: nucleus, microtubules and endoplasmic reticulum, are always shown in the blue, red and yellow channels, respectively. The channels can be toggled on and off by clicking on the respective coloured button above the image. When applicable, the immunofluorescent images are complemented by immunohistochemically stained cells where the location of the particular cell structure is shown in brown.
A common feature for all sections is that a general descriptive text about the tissue, tumor-type or cell structure is provided when browsing a particular topic.
Normal brain tissue is represented by four different regions: Cerebellum, Cerebralcortex, Hippocampus and Lateralventricle wall.
The nervous system represents the major communication network and consists of the central nervous system (CNS) and peripheral nervous system (PNS). The intracranial cerebrum and cerebellum together with the spinal cord constitutes the CNS. The brain is covered by layers of membranes, the meninges, and submerged in cerebrospinal fluid, which also fills the intracerebral ventricles. The brain can grossly be divided into different neuroanatomical functional regions such as the frontal, parietal, temporal, occipital lobes and central gray matter structures. Anatomically and histologically the brain can further be stratified into the cerebralcortex representing the outermost graymatter overlying whitematter and the innermost deep gray matter components. The hippocampus, containing the neuron rich dentatefascia, is closely associated with the cerebralcortex, and is located in the medial temporal lobe. The cerebralcortex incorporates neurons (nerve cells) and glialcells (supportive cells), whereas the white matter incorporates primarily glial cells and myelinated axons from neurons.
The brain parenchyma is composed of neurons embedded in a framework of glial cells (astrocytes and oligodendrocytes) as well as microglia and bloodvessels. The ependymal cell is also a specialized glial cell that lines the ventricles, including the lateralventricles, and is closely related to the cellular component of the cerebrospinal fluid producing choroidplexus. In addition to the cell bodies that can be defined in the microscope, cell processes from neurons and glial cells form a synaptically rich ?background substance? denoted as the neuropil. The cerebellum, important for coordination, appears as a highly ordered tissue with distinct layers including the cell dense granularlayer and the fiber rich but sparsely cell populated molecularlayer, between which the large Purkinjecells (specialized neuronal cells) are located.
The neurons are a morphologically and functionally heterogeneous family of cells that can transmit information through chemical and electrical signaling. Neurons vary in size from the small round cells that populate the internal granular layer of the cerebellum to the large pyramidal neurons of the primary motor cortex and the Purkinje cells of the cerebellum. Astrocytes represent the major glial cell type in the brain and are characterized by their cellular cytoplasmic processes reaching both synapses and capillary walls. The astrocyte is a star shaped cell involved in the maintenance of the microenvironment surrounding neurons and also important for the blood-brain barrier function. Oligodendrocytes are the main producer of myelin and are characterized by their small, rounded and lymphocyte like nuclei.
