LIFESCI 2 Lecture Notes - Lecture 17: Thyroid, Scrotum, Paracrine Signalling
Document Summary
Maintains blood-glucose & calcium levels: ex. ) Change in glucose or calcium causes a response that brings the level back to set point. > muscle/liver break down glycogen & release glucose --> increase in blood glucose. If blood-glucose levels control fails, diabetes mellitus happens: positive feedback provides acceleration of target cells response for a short time. Stimulus --> response -> more response -> so on. In endocrine system, stimulus leads to secretion of hormone that leads to a response that causes more hormone release. Reinforces itself until it"s interrupted or broken by some sort of external signal outside of loop. Stimulus --> sensor --> effector --> response --> sensor --> effector --> etc. Uterine contractions: oxytocin released from pituitary gland --> causes uterine muscles (effector) to contract --> contractions stimulate gland to secrete more oxytocin --> more contractions: hormones: 2 types, peptide & amines: hydrophilic so they cannot diffuse across membrane.
