HLSC 1F90 Lecture Notes - Lecture 14: Thyroid, Adrenal Gland, Autocrine Signalling
9 Mar 2018
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Document Summary
Chemical signals packaged in granules or secretory vesicles. Secreted by a cell or a group of cells. Activate physiological response at low concentrations (nanomolar to picomolar) Hormones are secreted by endocrine glands/ cells into the bloodstream. Only target cells with receptors for that specific hormone will respond to that signal. Neurohormones are chemicals released by neurons into the blood for action at distant targets. The action of hormones can be either autocrine or paracrine. Autocrine signals act on the same cell that secreted them. Paracrine signals are secreted by one cell, and diffuse to adjacent cells. Depends on binding to target cell receptors. May have different actions depending on the tissue or stage of development. Transport of ions or molecules across cell membranes. Typically, as a measure of the time needed to decrease its concentration in the circulation by 50% There are degrading enzymes in the circulation, liver and kidneys. Mrna on ribosomes binds amino acids into a peptide chain.
