01:119:116 Lecture Notes - Lecture 13: Ecdysteroid, Pituitary Gland, Prothoracicotropic Hormone
12 Jun 2017
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Control of hormone secretion: simple endocrine pathways. A. a)endocrine cells respond directly to stimulus: simple neuroendocrine pathways. B. a)stimulus received by sensory nerve first: feedback regulation. Prothoracic gland: gland in first part of thorax (a. a. 2. i) makes ecdysteroid. Jh: juvenile hormone stay immature (a. b. 1. i)as it grows up, there is less of this hormone (a. b. 2) Ptth: prothoracic hormone tell prothoracic gland to make ecdysteroid (a. b. 3) Ecdysteroids: molting hormones molt command to molt fat soluble (steroids are fat soluble: endocrine pathway: ptth & jh. B. a)after hatching, caterpillar increase levels of jh, no ptth, no ecdysteroid. B. b)caterpillar continues to eat and grows inside, as it keeps eating, tissue inside of caterpillar grows (muscles, organs) B. c) the outside skeleton and it grows until it is the size of the outside skeleton. B. d)stimulus = inside of insect pushing on endoskeleton (good example of positive regulation: pushing of body against exoskeleton, the more ecdysteroid is released) B. e)brain makes ptth which signals prothoracic gland which makes ecdysteroid.
