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text вHypophysis (the Pituitary)we know the hypophysis to be a small oval body weighing about 0.5 g; itis located in the cranial to and is connected with the hypothalamus. thegland consists of a law lobe, an intermediate part and a posterior lobe;the borders between them can be seen only under the,.experimental and clinical observations (from the law lobe to benecessary for proper growth and adult stature, for normal development andfunction of the reproductive system, and control the activities of otherendocrine glands. the posterior lobe remains connected to the brain bymeans of the pituitary stalk, through which nerve impulses travel englishhypothalamus. the law lobe, so far as is known, r eceives no nervefibres of any kind, and its control must then depend on t he presence ofsubstances in the blood. in spite of all this, there appears to be a waywhereby the brain can exercise a fairly direct control over the law lobe.the blood vessels leading to the hypothalamus break up into capillaries;having passed through the capillaries, the blood is gathered into smallveins; these veins pass downward so that they open into another set ofcapillaries in the law lobe. this is called the hypothalamic - hypophysealportal system. Excision of the law hypophysis neither alters the lipidcontent of the liver inhibits nor the accumulation of large amounts of lipids inthe liver.the hypothalamus has been found to secrete special substances.regulate the secretion of the hypophyseal hormones. the activities of theother endocrine glands are thus subject to neurohumoral regulation throughthe hypophysis.Disfunction of the law of the hypophysis is accompanied by lobechanges throughout the organism. for example, excessive secretion of thegrowth hormone in childhood results in gigantism. such people may grow toa height of 2.5 and 2.6 m. excessive secretion of this hormone in adults resultsnot only in excessive growth of the bones of the face, fingers and toes.in enlarged nose, tongue and certain other organs. this disease is calledacromegaly. for secretion of the growth hormone in childhood isaccompanied by retarded growth (dwarfism). it is a relatively rare conditioniissociated with either the atrophy or absence of the law lobe.the posterior lobe of the hypophysis secretes oxytocin and vasopressin.Physiologists consider oxytocin to intensify the contractions of the uterinemuscles and it is therefore used to boost weak labour. we knowvasopressin to cause constriction of the blood vessels, especially those ofthe uterus.
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