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Thread: Thyroid Gland, Trichrome Stain picture - Endocrine Histology Atlas

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    Default Thyroid Gland, Trichrome Stain picture - Endocrine Histology Atlas

    Study the pars distalis (anterior lobe) in the slide stained with Masson trichrome [example]. The cells are arranged in irregular clusters or cords and are distinguishable by their staining as either acidophils, basophils, or chromophobes. The acidophils stain red or orange-red, while the basophils stain various shades of blue or blue-gray. Remember that the acidophils include two different cell types, somatotropes (growth hormone) and mammotropes (prolactin), while the basophils include gonadotropes (FSH and LH), thyrotropes (TSH) and corticotropes (ACTH). ACTH is actually a cleavage product of pro-opiomelanocortin (POMC), which is made by corticotropes and processed primarily into ACTH in these cells. To a lesser extent, corticotropes also produce other signaling factors derived from POMC such as lipotropins (involved in lipid metabolism), endorphins (endogenous opioids that reduce pain perception), and melanocyte stimulating hormone (MSH). Occasional cells in the anterior pituitary show no distinctive staining and are called “chromophobes”. You will only be required to distinguish acidophils from basophils. Your best strategy is first to identify acidophils, which are more distinctively stained, and then the remaining cells are almost entirely basophils. The cells are not uniformly distributed throughout the pars distalis, but instead there are areas where acidophils predominate, other areas where basophils are more numerous, while still other regions may show a more even mixture of acidophils and basophils. What would be the most pronounced histological difference between the pituitaries of castrated and non-castrated males (assuming no hormone replacement)? (EN1) Note the abundant sinusoidal capillaries (often filled with red blood cells) [example] that lie between the cell cords or clusters. You can appreciate how readily the hormones secreted from the cells can reach the blood. Since collagen stains bright blue with the Masson trichrome method, you can see the delicate connective tissue partitions between cords and around blood vessels.
    In the routine H&E-stained sections, you can also identify acidophils and basophils, although the difference is not as obvious as it is with Masson trichrome staining. Here again, you should first identify acidophils, which stain various shades of reddish pink, and then the remaining cells are almost entirely basophils, which vary generally from bluish/grayish-pink to blue.

    Although the pars nervosa can be found on the human pituitary slides in our collection, the monkey pituitary specimens (H&E and trichrome-stained) contain a significant portion of the pars nervosa (posterior lobe) [example] and are probably better for studying this tissue. The pars nervosa looks like brain tissue, which it is. It is an extension of the brain, composed primarily of nerve fibers (axons) which originate from nerve cell bodies in the hypothalamus and pass to the pars nervosa by way of the hypothalamo-hypophyseal tract and the infundibular stalk. These nerve fibers carry oxytocin and antidiuretic hormone (ADH, vasopressin) to nerve endings, from which they are released into nearby capillaries upon neural stimulation from the hypothalamus. There is not much to see in the posterior lobe in these histological sections. Since there are no neuron cell bodies in this structure, most of the prominent nuclei belong to pituicytes [example], which are the characteristic glial cells of the pars nervosa. You will also see the nuclei of blood vessel endothelial cells [example], and fibroblasts which are in the connective tissue around these vessels.

    1. Zona glomerulosa, the outermost zone of the adrenal cortex secretes mineralcorticoids. These hormones are important for fluid homeostasis. These include aldosterone, which regulates absorption/uptake of K+ and Na+ levels in the kidney.
    The secretory cells are arranged in irregular ovoid clusters that are surrounded by trabeculae which contain capillaries. Can you identify them?
    The nuclei stain strongly, and the cytoplasm is less pale than that of the next zone, the zona fasciculata, as there are fewer lipid droplets in these cells.

    2. Zona fasciculata, the middle zone of the adrenal cortex secretes glucocorticoids which are important for carbohydrate, protein and lipid metabolism. An example is cortisol which raises blood glucose and cellular synthesis of glycogen. Its secretion is controlled by a hormone from the pituitary - ACTH.
    The secretory cells are arranged in cords, often one cell thick, surrounded by fine strands of supporting tissue. Can you identify them?
    The nuclei of these cells stain strongly, and the cytoplasm is rich in sER, mitochondria and lipid droplets. The cytoplasm looks pale and 'foamy' due to the presence of lipid droplets.

    3. Zona reticularis, the innermost layer of the cortex, secretes sex hormones (androgens). and small amounts of glucocorticoids. These hormones are secreted by the inner zone of the cortex, which is called the zona reticularis.
    Some brown pigment is seen in some of these cells - this is lipofuscin, probably an insoluble degradation product of organelle turnover - an 'age' pigment. The cytoplasm of the cells in this region stains more darkly, and contains fewer lipid droplets.

    Results and Discussion
    The thyroid glands were encapsulated by a
    capsule whi ch consisted of well developed
    collagen fibres, reticular fibres and very few
    elastic fibres. It was frequently thickened in
    areas where small arteries, veins and nerves
    were present on the surface of the gland as
    reported by Hodges (1974). The capsule was
    made up of three layers. The external layer
    was a mesothelial layer lined with simple
    squamous epithelium, the middle layer was rich
    in fat cells, blood vessels and nerves and the
    inner layer was closely adherent to the gland.
    Yaswant Singh and Bharadwaj (1982) reported
    the same three layers as outer "Capsule serosa",
    middle "Capsule adiposa" and the innermost
    "Capsule fibrosa" in the White Leghorn chicken.
    The reticular fibres were more in younger
    age groups than in older and were replaced by
    collagen fibres with aging. Hence in older age
    groups the collagen fibres predominated at the
    expense of r e t i c u l ar fibres. The increased
    production of thicker collagen fibrils masked
    Thyroid Gland, Trichrome Stain picture attachment.php?s=c788ed5dddd0ec6417e50e3c405d82ed&attachmentid=1312&d=1439059476

    Addison’s disease is an uncommon autoimmune disease, characterized by chronic and insufficient functioning of the outer layer of the adrenal gland. The adrenal glands are located atop each kidney and produce vital glucocorticoid hormones. Because of this chronic under-functioning of the adrenal glands, persons with Addison’s disease have a deficiency in the production of glucocorticoid hormones. Glucocorticoid hormones are involved in how the body utilizes and stores carbohydrates, protein, fat and blood sugar.

    The adrenal gland also plays a role in the immune response. A deficiency in glucocorticoid hormones causes an increase in the release of sodium and a decreased release of potassium in the urine, sweat, saliva, stomach and intestines. These changes can cause low blood pressure and increased water excretion that can in some cases lead to severe dehydration.

    Although there are many underlying factors in the development of adrenal insufficiencies, including destruction of the adrenal cortex due to diseases such as tuberculosis, the growth of tumors, non-autoimmune diseases amyloidosis and adrenoleukodystrophy, and atrophy of the gland due to prolonged use of cortical steroids used in the treatment of other conditions and illnesses, most cases of Addison’s disease are thought to be autoimmune in nature.

    Agammaglobulinemia is an immune disorder related to antibody deficiency (hypogammaglobulinemia) and is manifested in a variety of immune deficiency disorders in which the immune system is compromised. This group of immune deficiencies may be the consequence of an inherited condition, an impaired immune system from known or unknown cause, a relation to autoimmune diseases, or a malignancy.

    Immunoglobulin deficiencies may be referred to by many different names, as there are several variables within the separate but related immune disorders; and there are also many subgroups. Antibody deficiency, immunoglobulin deficiency, and gamma globulin deficiency are all synonyms for hypogammaglobulinemia.

    Alopecia areata is an autoimmune disorder which is characterized by hair loss. Alopecia areata is found equally in both men and women. The disease can occur at any age, including childhood.

    The hair loss may result in round bald patches on the scalp (alopecia areata) or involve the loss of all facial and scalp hair (alopecia totalis). The loss of all body hair is called alopecia universalis. Alopecia postpartum is characterized by loss of significant hair following pregnancy and is usually temporary. When a patient is diagnosed with alopecia, the first question is usually about whether or not the hair will regrow. The answer is usually vague as each case is different. Regrowth of hair may occur in some patients; and in other, the hair loss is permanent.

    Amyloidosis is a disorder in which abnormal proteins build up in tissues and organs. The cause of primary amyloidosis is unknown. The condition is related to abnormal and excess production of antibodies by a type of immune cell called plasma cells. Clumps of abnormal proteins build up in certain organs. This reduces their ability to work correctly. Symptoms depend on the organs affected. This disease can affect the tongue, intestines, skeletal and smooth muscles, nerves, skin, ligaments, heart, liver, spleen, and kidneys. Symptoms include: abnormal heart rhythm, fatigue, numbness of hands or feet, shortness of breath, hoarseness or changing voice, and joint pain.

    References:
    http://www.aarda.org/descriptions-of...n'sdisease
    http://www.cvaslibrary.com/journals/1_31_8.pdf
    Histology Guide | Glandular
    Medical Histology and Virtual Microscopy: University of Michigan











    Last edited by Medical Photos; 08-08-2015 at 06:44 PM.

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