BIOLOGY 2A03 Lecture Notes - Lecture 5: Posterior Pituitary, Endocrine System, Prolactin
22 Feb 2018
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Lecture 5: signaling & endocrine systems part 2. Is a long distance communication system in our body, along either the nervous system. Hormone actions will have a slower onset but are longer-lasting than other forms of chemical communication. Evolved independently along with circulatory system of animals. Primary endocrine organs - releasing hormones is the primary role of these organs. Secondary endocrine organs - releasing hormones is a secondary role. Endocrine system interacts with the nervous system (ns) Axons from hypothalamus terminate in posterior pituitary where they release neurohormones into the blood. Posterior pituitary - composed of neural tissue (aka neurohypophysis in mammals) Short peptides (8-9 amino acids) synthesized in the cell bodies of giant neurons of the hypothalamus. These are transported down the axons and stored in synaptic vesicles in terminal knobs (similar to neurotransmitters) at blood vessels in posterior pituitary. Released in response to low blood volume, low blood pressure, or high ecf osmotic pressure (detected by hypothalamic osmoreceptors)
