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.
The human heart is in essence a coordinated muscle that flushes 6,000 liters of blood through the body daily during a lifetime. The underlying heart muscle is highly vascularized and under nervous control to set the pace of heart beats. The cardiac muscle (myocardium) together with the skeletal muscles are composed of striated muscle tissue that form parallel musclefibers. Different to skeletal muscle, cardiac muscle cells may be branched instead of organized as parallel linear fibers. Striated muscle tissue of heart consists of cardiomyocytes arranged in fibers that exhibit cross-striations formed by alternating segments of thick and thin protein filaments.
The major cell type is cardiomyocytes, which usually contain one or two nuclei. The cells are rich in mitochondria and to a large extent contain actin and myosin proteins arranged in a repeating unit called a sarcomere. Histologically, this highly structured arrangement of sarcomeres appears as dark (A-bands) and light (I-bands) bands, which are clearly visible in the microscopic image. In addition to the muscle fibers, the myocardium also includes streaks of connective and cuffs of adiposetissue surrounding the smaller vessels. The cardiac muscle tissue is highly vascularized through the feeding coronary arteries that branch into smaller vessels that end in a dense network of capillaries running in between the fibers.
