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Showing posts from September, 2017

Thymus

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Thymus of Human Organ The thymus is a vascular organ of the lymphatic system situated just behind the breastbone. The human thymus continuous to grow for about a year after birth, reaching a weight of about 42 g; this size is maintained until puberty. After puberty the lymphatic tissue is replaced by fat, but the thymus remains functional throughout life. Thymus The main function of thymus is to process lymphocytes received from the blood producing bone marrow and fetal liver. These cells proliferate and differentiate in the thymus into thymic lymphoid cells called T cells, each one programmed for the number of antigens to which it will react. In humans the cellular immune system requires the presence of the thymus at birth; this system allows the body to recognize foreign, that is “non self” tissue and to attack malignant cells, viral infection, fungal infection, and some bacteria. Little is known of the factors and processes of thymic function. The importance of the thymu

Thyroid Gland

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Thyroid Gland Thyroid Gland and Endocrine Gland The thyroid, and endocrine gland, synthesizes stores and secretes two hormones, thyroxine or tetraiodothyronine (T4), and triiodothyronine (T3), that are chemically related and important to human growth and metabolism. Located below the larynx (voice box), the thyroid’s two lobes occurs on either side of the wind-pipe, connected by an isthmus (band of tissue). The gland is composed of many hollow sacs (follicles) filled with colloid (a gelatin material), which contains thyroglobulin, the storage form of the hormones. Essential to the synthesis of the hormones is inorganic iodide, which diffuses from citonin of calcitonin, acts against excessive levels of calcium in the blood and against the effects of parathyroid hormone on bone resorption. Thyroid hormone secretion is controlled by thyroid stimulating hormone (TSH), or thyrotropin, from the anterior pituitary. In turn the resultant increase in the level of thyroid hormones in the b

Kidney Structure

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Human Kidney and Function of Kidney Kidney is a human organ  like kidney beans shaped. In humans, kidney size, which is a length of 10 to 12 cm, width 5-6 cm, and thick, 3-4 cm, weighing about 140 grams. In cross kidneys, visible parts are different. The sections are from outside into the cortex, medulla, and pelvis. In the renal cortex and medulla there are about 1 million nephrons. Nephron is the structural and functional unit of the smallest of the kidney. Nephron serves as a screening tool. Human Organ Nephron is shaped like a large worm-headed eagle with a body like the winding. At the head there is a fine mesh that can only be bypassed by certain substances. Blood cells and blood proteins can not pass through this filter because it was bigger. The composition of the nephron consists of the following sections. 1) Malpighian Body, which includes Bowman's capsule and glomerulus. 2) convoluted tubules including proximal tubules, Henle, and distal tubules. Some tu