Summary of Endocrine System - 1 Summary of Endocrine System...

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1 Summary of Endocrine System A. Pituitary Gland – the “master gland” 1. Posterior = neurohypophysis consists of pars nervosa and infundibulum (pituitary stalk). Neurons in the supraoptic and paraventricular nuclei (ganglia) in the hypothalamus make ADH and oxytocin . These hormones are then transported through the axons to the posterior pituitary. The axons pass through the infundibulum to reach the posterior pituitary. The two hormones are stored in the dilated ends of the axons (Herring bodies). We say ADH and oxytocin are the two hormones of the posterior pituitary but they are really made by neurons in the hypothalamus and stored in axons in the posterior pituitary. Most of the posterior pituitary is occupied by axons but there are some glial like cells called pituicytes. ADH and oxytocin are small peptide hormones (nine amino acids). 2. Other neurons in the hypothalamus produce peptide hormones that are stored in their axons that lie in the median eminence (basically the top of the infundibulum). These hormones are the Releasing (and I nhibitory ) hormones that are secreted into the primary capillary bed of the hypophyseal portal system. This primary capillary bed reforms into veins ( portal veins ) which again break up into capillaries in the anterior pituitary. For example, thyrotropin-releasing hormone is made by a neuron in the hypothalamus, transported in the axon, and released on to capillary in the
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2 median eminence. From there, the hormone passes though the portal vein to enter the secondary capillary bed in the anterior pituitary where it leaves the capillary to act on the basophil cell
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This note was uploaded on 11/08/2011 for the course SCIENCE 3254 taught by Professor Dr.shoupe during the Spring '11 term at Fort Valley State University .

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Summary of Endocrine System - 1 Summary of Endocrine System...

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