PHSI 208 Lecture Notes - Lecture 5: Walter Bradford Cannon, Mass Balance, Hemoglobin
Document Summary
Answer: actin and mysoin can not form enough crossbridges with each other because they cannot couple and uncouple fast enough. Myosin is sliding past actin too quickly. Because cells need o(cid:454)(cid:455)gen and rbc"s bring it to them. Oxygen binds to hemoglobin molecules in the red blood cells. Homeostasis: the ability to maintain a relatively stable internal environment in spite of exposure to external variability, key principle in physiology, ex: blood pressure, body temp, ion/molecule concentration, gas partial pressures, term coined by walter cannon: Homeo = like or similar (range of values) Stasis = condition (not a static state: external change: toxic chemicals, physical trauma, foreign invaders (bacteria or viruses) Internal change: abnormal cell growth, autoimmune disorders, genetic disorders: depends on mass balance: Law of mass balance: the amount of a substance in the body is to remain constant, any gain must be offset by an equal loss. Mass balance= existing body load+ intake or metabolic production excretion or metabolic removal.
