F ever Jianzhong sheng md, phd Department of Pathology pathophysiology School of Medicine, Zhejiang University Email: shengjzazju.edu.cn
Fever Jianzhong Sheng MD, PhD Department of Pathology & Pathophysiology School of Medicine, Zhejiang University Email: shengjz@zju.edu.cn
Body temperature Normal body temperature 37C( set point,体温调定点) Circadian variation olT0.5> axillary T(腋温)
Body temperature •Normal body temperature: 37oC (set point，体温调定点) Circadian variation oral T 0. 5oC > axillary T（腋温）
F ever Pyrogens (exogenous or endogenous) Elevated set-point Maintaining an abnormally elevated Temperature BMR(basal metabolic rate) increases BMR个10% T个0.6°C T个= Elevated set-point
Fever Pyrogens (exogenous or endogenous) Elevated set-point Maintaining an abnormally elevated Temperature BMR (basal metabolic rate) increases T = Elevated set-point BMR 10% = T 0.6oC
Hyperthermia(过热) e fever due to a disturbance of thermal regulatory control excessive heat production (e.g. vigorous exercise, a reaction to some anesthetics decreased dissipation (e.g. dehydration loss of regulation (injury in the hypothalamic regulatory center)
Hyperthermia (过热） •Fever due to a disturbance of thermal regulatory control excessive heat production (e.g. vigorous exercise, a reaction to some anesthetics) decreased dissipation (e.g. dehydration) loss of regulation (injury in the hypothalamic regulatory center)
Hyperthermia Excessive heat Decreased Loss of production dissipation regulation T>unchanged set-point
Hyperthermia Excessive heat production T > unchanged set-point Decreased dissipation Loss of regulation
Pathophysiology Body temperature is determined by two opposing processes heat production heat loss They are regulated by the central nervous system Energy in the form of heat is generated by living tissues( thermogenesis生热作用) Energy may be passively absorbed from the environment and may be transferred to the surrounding medium
Pathophysiology •Body temperature is determined by two opposing processes heat production heat loss • They are regulated by the central nervous system • Energy in the form of heat is generated by living tissues (thermogenesis 生热作用) • Energy may be passively absorbed from the environment and may be transferred to the surrounding medium
Heat production Increased BMR, by varying the level of circulating thyroxine(甲状腺素) ( controlled by hypothalamus下丘脑) Increased muscle sensitivity(shivering
Heat production •Increased BMR, by varying the level of circulating thyroxine （甲状腺素) ( controlled by hypothalamus 下丘脑) •Increased muscle sensitivity (shivering)
Heat loss .By varying the volume of blood flowing to skins surface(>100 fold) By vaporization(exocrine sweating
Heat loss •By varying the volume of blood flowing to skin’s surface (>100 fold) •By vaporization (exocrine sweating)
Pathophysiology The body temperature is under control of the preoptic area of the anterior hypothalamus (视前区下丘脑前部) Thermostat(恒温器) .lt receives input from both central receptors and peripheral receptors
Pathophysiology •The body temperature is under control of the preoptic area of the anterior hypothalamus （视前区下丘脑前部） Thermostat （恒温器） •It receives input from both central receptors and peripheral receptors
Pathophysiology Elevation of body temperature shivering thermogenesis and dermal vasoconstriction sympathetic(交感神经) outflow Cooling mechanism sweating and dermal vasodilation mixture of sympathetic and parasympathetic pathways
Pathophysiology •Elevation of body temperature shivering thermogenesis and dermal vasoconstriction sympathetic (交感神经）outflow •Cooling mechanism sweating and dermal vasodilation mixture of sympathetic and parasympathetic pathways