MCELLBI 32 Lecture Notes - Lecture 2: Mass Balance, Thermoreceptor, Homeostasis

• School: Berkeley
• Department: Molecular And Cell Biology
• Course: MCELLBI 32
• Professor: Robin Ball

Document Summary

Mcb 32 lecture #2 - introduction to homeostasis: homeostasis, what is homeostasis, mass balance: what goes in must come out, helps maintain homeostasis, existing body load + intake/metabolic production + excretion/metabolic removal = mass balance. Internal environment is stable, but not totally constant. A. heater (causes the response: maintains homeostasis, very common in body. Input: a stimulus is measured by a sensor. Sensors are often neurons that can measure chemicals or temperature. Integration: something needs to take the information from the sensor and compare it to the set point = integrating center (nervous or endocrine system usually: response: integrating center relays signals to cells/tissues (effectors) that bring about final response. Cold day body temperature (stimulus) thermoreceptors sense temperature in skin and hypothalamus (sensors) hypothalamus signals effectors (integrating center) skeletal muscles contract (effectors) shivering (response) produces heat (response) increase body temperature. Also the blood vessels can restrict (effector) vasoconstriction (response) heat loss through the skin decreases.