6A Flashcards
(14 cards)
What is homeostasis
Homeostasis is a complex process that maintains the internal environment of an organism within set limits so that cells and systems can function properly
What happens if cell parameters are not met
Cells within our bodies like to exist within a set range of parameters
If these parameters are not met, then cells can’t function normally and may potentially become damaged or die
What parameters affect the functioning of cells
Temperature (optimal body temp 36.5oC – 37.5oC)
pH (acidity level -optimal pH of blood is 7.35 – 7.45)
Blood sugar levels (blood sugar levels are maintained between 4.0 – 7.8 mmol/L)
Sodium and potassium concentration (normal levels are 135-145 mmol/L for sodium & 3.5 – 5.0 mmol/L for potassium)
Fluid balance
What is the purpose of homeostasis
Homeostasis aim is to maintain an internal environment that is just right for our cells.
what are the homeostatic mechanisms
All the homeostatic mechanisms can be described using a stimulus-response model and positive and negative feedback systems.
what are the homeostatic mechanisms
All the homeostatic mechanisms can be described using a stimulus-response model and positive and negative feedback systems.
five parts of the stimulus response model
Stimulus
Receptor
Modulator/s
Effector
response
5 types of receptors
thermoreceptors- temperature
nociceptors- pain
baroreceptors- pressure
chemoreceptors- chemical concentration
photoreceptors- light
whats the positive feedback system
Positive feedback systems occur when the response increases the initial stimulus. They are rare in the body and don’t form part of homeostasis. An example is the production of breast milk in feeding mothers.
whats the negative feedback system
Negative feedback systems occur when the response counters the stimulus – the response attempts to revert the system back to the state it was in before the stimulus occurred. This point is known as the set point, and it’s the value the body aims to maintain a given variable at.
what is cellular signalling
When discussing the stimulus response model at a cellular level is it represented as a 3 step process – reception, transduction and response
The same processes occur as in the five step process, although they’re grouped together a little differently
what happens in reception for cellular signalling
the detection of a stimulus and the transmitting of this stimulus into a mechanical, electrical or chemical signal
whats transduction in cellular signalling
transmission of a signal during cellular signalling. The transduction stage of the stimulus response model follows the detection of a stimulus and includes everything up to the final response of a cell or organ. Transduction can involve sending a signal between organisms, across the body, to a neighbouring cell or back to the original receptor cell
whats the response in cellular signalling
the change in the function of a target cell, organ or organism
