PSL300H1 Lecture Notes - Lecture 1: Chemical Substance, Homeostasis, Endocrine Gland
Document Summary
Physiology - is the science of how we stay alive and healthy. The constancy of the internal environment claude bernard, 1880"s. Homeostasis , regulation of the internal environment walter b. cannon, 1929. Holding an internal environment constant despite changing conditions. K intracellular=na extracellular: this critical for neuro function. Classical definition: a substance secreted from a cell/cluster of cells into the bloodstream and exerting a regulatory action at low concentration on a distant target. Nuanced definition: a chemical substance secreted by a cell acting at low concentrations via specific receptors to regulate target cellular functions. (the agent and substance work locally; doesn"t have to be in the bloodstream) Neuroendocrine: corticotropin releasing factor secreted by the hypothalamus. Endocrine cell: polarized, sensory end of the cell, Do not lead to the outside of the body. Endocrine gland secrete hormones directly into the blood. Regulating homeostasis and other body functions by hormones works by. E. g. oxytocin and the control of uterine contractions.
