Homeostasis - "Staying or Standing the same"
Examples of Homeostasis
-Temperature Regulation -Regulation of blood carbon dioxide level -Regulation of blood glucose level The body adjusts important variables from normal "set point" in order to get the body back into an acceptable or normal range (i.e. blood pressure)
Negative Feedback
-They oppose a change by creating a response that is opposite in direction to the initial disturbance -Drop in temperature (change) production of heat (response) -Stabilize physiological variables (keep them from going beyond the normal range) -Are responsible for maintaining homeostasis -Are much more common than positive feedback control systems -Example: Body Temperature Control or Blood Pressure
Basic components of control mechanisms
1. Variable - such as blood pressure, oxygen concentration, or temperature. 2. Sensory mechanism (receptor)- specific sensors that detect and react to any changes from normal. Ex.- Nerve 3. Integrating, or control, center- where the information is analyzed and integrated, and then, if needed, a specific action is initiated. Ex. CNS or Thyroid 4. Effector Mechanism - effectors directly influence controlled physiological variables Ex. Muscle or glad 5. Feedback - processes information about a variable and constantly sends information back from the sensor to the integrator (control)
Homeostatic control mechanisms
A device for maintaining or restoring homeostasis by self-regulation through feedback control loops
Positive Feedback
The effector produces a physiological response that reinforces the initial change in the controlled condition and: -Are stimulatory -Amplify or accelerate the change that is occurring -Tend to disrupt homeostasis -Bring specific body functions to swift completion -Example: Childbirth, Clotting, Immune Response, or Sneeze
Homeostasis
The term used to describe the relatively constant states maintained by the body's internal environment. -Coined by Walter B. cannon in 1932 -The body maintains homeostasis through feedback systems
