Lecture 25 Flashcards
What is homeostasis - balance
- a relatively constant internal environment that supports cell functioning and life processes
- human body systems keep each regulated variable withen an original range
Imbalance - loss of homeostasis
- as cells function, they use up nutrients and produce biproducts
- example = during growth, reproduction, exercise, stress and illness
What is regulated variable
A variable for which there is a sensor and a system to ensure the variable is kept withen a normal range, around a set point
What are examples of regulated physiological variables
- core temperature
- plasma gluclose concentration
- plasma calcium concentration
- basal metabolic rate
And many more
Regulated variables, Normal range
The restricted set of variables for a regulated variable, that permits optimal cell functioning
Regulated variable, set point
- the physiological value of any given variable, around which its normal range fluctuates
- each person has a unique set-point for each variable based on genetics and other factors
What is the set point
This is the target value for which the system aims to maintain
What is the normal range
The normal rage is rages that are a range of values that are around the set point
Control system for non physiological example, so if we are thinking about temperture
control system is responsible for regulating the room temperature to keep it within the normal range around the set-point. In this example, the control system consists of a thermostat connected to a heat pump. The thermostat continuously monitors the current room temperature and compares it to the set-point. If the temperature deviates from the set-point, the thermostat sends signals to the heat pump to adjust its operation accordingly. For instance, if the room temperature rises above the set-point, the heat pump activates the cooling function to lower the temperature back to the desired level. Conversely, if the temperature drops below the set-point, the heat pump switches to heating mode to warm up the room.
What is a physiogical example if we are talking about normal range and set point
If we were discussing the regulation of body temperature in a living organism, such as a human, it would be a physiological example because it involves the natural processes that occur within the body to maintain temperature homeostasis.
What is a non-physiological example
On the other hand, the room temperature control scenario is a non-physiological example because it pertains to the regulation of temperature in an artificial environment (a room) using a mechanical system (a thermostat connected to a heat pump). It does not involve biological processes or living organisms.
What is population refernace rage
The set of values for a regulated variable that are considered normal and/or healthy and it tends to be wider than any given individuals normal range
Population refernace range vs individuals normal range
- most indivuals will have a set point that is withen the population refernace range
- remember the normal range fluctuates around the set point for any given variable
And so if the variable was to move outside the normal range this may lead to deasises or symptoms of a disorder
This can even occur if the variable is in the population refernace range
Homeostasis of regulated variables: NEGATIVE FEEDBACK FOR BALALCE
A negative control loop keeps a regulated variable in its normal range around the set point,-
-if the variable was to go up the negative feedback will bring it down
- if the variable was to go down, the negative feedback will bring it up
What is the negative feedback control loop
- sensors : this monitors the variable and directs changes
- control centre - this compares the variables changed value to its set point and it send signals to effectors if correction is required
- effectors - these act to oppose the effect of the stimulus, meaning it corrects the change and restoring the variable to its setpont
