Proglottids are continually being produced by the neck region of the scolex, as long as the scolex is attached and alive.Mature proglottids are essentially bags of eggs, each of which is infective to the proper intermediate host. They are released and leave the host in feces, or migrate outwards as independent motile proglottids. The number of proglottids forming the tapeworm ranges from three to four thousand. Their layout comes in two forms: craspedote, meaning any given proglottid is overlapped by the previous proglottid, or acraspedote, indicating the proglottids do not overlap. Reproduction
Cestodes are exclusively hermaphrodites, with both male and female reproductive systems in each body. The reproductive system includes one or more testes, cirri, vas deferens, and seminal vesicles as male organs, and a single lobed or unlobed ovary with the connecting oviduct and uterus as female organs. The common external opening for both male and female reproductive systems is known as the genital pore, which is situated at the surface opening of the cup-shaped atrium. Though they are sexually hermaphroditic and cross-fertilization is the norm, self-fertilization sometimes occurs and makes possible the reproduction of a worm when it is the only individual in its hosts gut. During copulation, the cirri of one individual connect with those of the other through the genital pore, and then spermatozoa are exchanged. Life cycle
Cestodes are parasites of vertebrates, with each species infecting a single definitive host or group of closely related host species.
A goitre, or goiter, is a swelling in the neck resulting from an enlarged thyroid gland. A goitre can be associated with a thyroid that is not functioning properly. Worldwide, over 90% of goitre cases are caused by iodine deficiency. The term is from the Latin gutturia, meaning throat. Most goitres are not cancerous (benign), though they may be potentially harmful. Signs and symptoms
A goitre can present as a palpable or visible enlargement of the thyroid gland at the base of the neck. A goitre, if associated with hypothyroidism or hyperthyroidism, may be present with symptoms of the underlying disorder. For hyperthyroidism, the most common symptoms are associated with adrenergic stimulation: tachycardia (increased heart rate), palpitations, nervousness, tremor, increased blood pressure and heat intolerance. Clinical manifestations are often related to hypermetabolism, (increased metabolism), excessive thyroid hormone, an increase in oxygen consumption, metabolic changes in protein metabolism, immunologic stimulation of diffuse goitre, and ocular changes (exophthalmos). Hypothyroid people commonly have poor appetite, cold intolerance, constipation, lethargy and may undergo weight gain. However, these symptoms are often non-specific and make diagnosis difficult.According to the WHO classification of goitre by palpation, the severity of goitre is currently graded as grade 0, grade 1, grade 2. Causes
Worldwide, the most common cause for goitre is iodine deficiency, commonly seen in countries that scarcely use iodized salt. Selenium deficiency is also considered a contributing factor. In countries that use iodized salt, Hashimotos thyroiditis is the most common cause.