PGY 412LEC Lecture Notes - Lecture 5: Tropic Hormone, Anterior Pituitary, Posterior Pituitary
20 Dec 2018
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Much slower than nervous system; like radio broadcasting. Negative feedback: to control when have enough (factory business) Dependent on circulating substrates (calcium, sodium, hormones) Ultra short feedback: hormone itself feedback on the target organ or tropic. Short feedback loop: tropic hormones affecting hypothalamus, hormone affecting. Long feedback loop: hormones feedbacks to hypothalamus hormones having effect on the anterior pituitary anterior pituitary. If have hormone all the time, the receptor loses its sensitivity. Upregulation means, more receptors and hence more sensitive to hormones. As we age hormones decrease, stress, cycles, endocrine pathologies. Anterior pituitary (adenohypophysis): derived from buccal cavity. Hypothalamic control occur via hypothalamic pituitary portal vascular system. Prolactin, gh, acth, tsh, lh (sex characteristics), fsh(testis and ovaries) Connected to hypothalamus by a stalk like structure. Siada (syndrome of inappropriate adh secretion): high levels of adh without normal stimuli. Neurogenic: inability of the ht to secrete/ synthesize adh. Hypopituitary: pituitary insufficiency because of the size, usually hyposecretion)
