EHS 385 Lecture Notes - Lecture 3: Critical Role, Cellular Stress Response, Hyperglycemia
9 Dec 2017
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Chapter 2 lecture 3 oc control of the internal environment. Homeostasis: maintenance of a constant and normal internal environment. Steady state: physiological variable is unchanging but not necessarily normal, balance b/t demands placed on body and body"s response to those demands: ex. Intracellular control systems: protein breakdown and synthesis, energy production, maintenance of stored nutrients. Organ systems: pulmonary/circulatory systems: replenish o2 and remove co2. Most control systems work via negative feedback. Ex: initiation of childbirth stimulates receptors in cervix, sends message to brain, release of oxytocin from pituitary gland, oxytocin promotes increased uterine contractions. Failure of a biological control system results in disease. Failure of any component of a control system results in a disturbance in homeostasis. Ex: type 1 diabetes, damage to beta cells in pancreas, insulin no longer released in blood, hyperglycemia results, represents failure of effector . Exercise disrupts homeostasis by changes in ph, o2, co2, and temp.
