BIO 012 Lecture Notes - Lecture 6: Blood Sugar Regulation, Blood Sugar, Positive Feedback
12 Jun 2018
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Chapter 40 – Physiology, Homeostasis, and Temp Regulation 9/14/17
40.1 How do Multicellular Animals Supply the Needs of Their Cells
The goal is to maintain a stable internal environment.
Physiological systems are regulated to maintain homeostasis.
- Physiological variables of the body are maintained within a predictable range (set points).
- Homeostasis is a dynamic, (it is ongoing and set points can shift over time) (ex: blood sugar
fluctuates over the day, temperature decreases overnight) not a static process.
- Variables can change dramatically over a 24-hour period, but the system is still in overall
balance.
Maintaining set points through feedback systems.
- The thermostat sensor responds to the temperature of the air, providing feedback – info that
its compared with the set point.
- Any difference between the set point and the air temperature is an error signal.
- Effectors effect changes in the internal environment. (ex: nervous system)
General Process
Setpoint →Sensor →Integrating Center (which is machinery that receives info from sensor and decides
what to do with it – usually is the nervous system but not always) →Effector (something that creates
change – getting back to the setpoint) → Setpoint Environment (When the environment changes the
set point, the sensor senses it and works to make change to bring you back.)
- Negative feedback – effectors cause an effect which stops the loop (reduction in activity
where the effector turns itself off) (ex: blood sugar regulation)
Environment
(alters variable) Sensor senses difference
Integrating Center
Set point changes (Starts to work to find what to
do to get back to set point. Then
it initiates the effector.)
(Fixes problem: Effector causes change
Sensor senses this and tells (To get variable back to set point)
integrating center to stop the effector)
- You eventually should get a negative feedback point in the process.
- Positive feedback – effectors cause an effect which continues the loop (magnifies effect) (ex:
birth → to get baby out magnifies)
- Regulatory systems obtain, process, and integrate info, then issue commands to controlled
systems. Important components of any regulatory system are the sensors.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Chapter 40 physiology, homeostasis, and temp regulation. How do multicellular animals supply the needs of their cells. The goal is to maintain a stable internal environment. Physiological variables of the body are maintained within a predictable range (set points). Homeostasis is a dynamic, (it is ongoing and set points can shift over time) (ex: blood sugar fluctuates over the day, temperature decreases overnight) not a static process. Variables can change dramatically over a 24-hour period, but the system is still in overall balance. The thermostat sensor responds to the temperature of the air, providing feedback info that its compared with the set point. Any difference between the set point and the air temperature is an error signal. Effectors effect changes in the internal environment. (ex: nervous system) Negative feedback effectors cause an effect which stops the loop (reduction in activity where the effector turns itself off) (ex: blood sugar regulation)
