Homeostasis Flashcards
What are the types of signalling molecules?
Endogenous
Exogenous
- type 1
- type 2
What are endogenous signalling molecules?
Signalling molecules from within the body
What are exogenous type 1 signalling molcules?
Signalling molecules that are external to the body, but natural e.g. plant-based
What are exogenous type 2 signalling molecules?
Signalling molecules that are man-made
What is homeostasis?
Keeping the extracellular environment stable
What are some examples of conditions in the extracellular environment that are kept stable?
Temperature
Water
Oxygen, carbon dioxide
Ions
pH
Glucose
What are the components of a homeostatic control system?
Sensor
Controller
Effector
What is the set point?
Normal levels of condition
What is a stimulus?
Change in levels of a condition to being too low or too high
What are the functions of a sensor?
Detects levels of condition under control
In response to stimulus, produces signals that run to controller
What are the functions of a controller?
Produces signals that run to effectors
What determines the size of the signal sent to the controllers, effectors etc.?
The difference between the set point and what the sensors detect
What are the functions of an effector?
Bring about the change in condition back to normal
What is negative feedback?
Change away from set point results in mechanism that reverses the direction of change and brings levels back to set point
What are the different ways by which different control feedback loops can interact with each other?
Synergistically - work together to produce same effect
Antagonistically - oppose the effects of one another
Are synergistic or antagonistic feedback loops more physiologically useful? Why?
Antagonistic feedback loops
give more precise control of condition levels
What is the normal body temperature range?
36-38C
Why is normal body temperature range 36-38C?
Proteins function optimally at this temperature
Reduces rate of denaturation of proteins
Where are the sensors of core body temperature located?
Hypothalamaus
Where are the sensors of peripheral body temperature located?
Skin
What are the mechanisms to increase body temperature?
Peripheral blood vessels constrict, reducing heat loss from skin surface
Skeletal muscle shivers, generating heat
What are the mechanisms to decrease body temperature?
Peripheral blood vessels dilate, fill with warm blood, heat radiates from skin surface
Sweat glands are activated, heat lost by evaporation
What is the dynamic range of a condition?
Levels outside of the normal range
but system itself and the control system can still function in this range
What happens if the levels of a condition go outside of the dynamic range?
Control system function is affected
system itself is affected
