medical sciences and homeostasis Flashcards
What is homeostasis
Homeostasis prevents disturbance in the system and it’s applied in the body to monitor the relatively constant internal environment in which all processes work optimally
Why is it important to maintain constancy of the internal environemnt
Bodies aren’t tolerant to change in the internal environment and failure to correct these imbalances can lead to illness and disease.
What are the principles behind negative feedback control systems
It’s the key mechanism by which homeostasis is maintained. It brings homeostasis back to normal range and brings regulated conditions back.
What is feed forward control
it’s a very sophisticated form of negative feedback control. It predicts theres going to be a disturbance and limits further damage by performing appropriately, until NFC can restore condition back to normal.
What is a positive feedback system
PFS have the opposite effect to NFS and they set off a chain of events that lead to more disturbance. They are rare in normality but more common in pathophysiology. Do occur in nerve action potential
Identify and describe the bodily fluid compartments
- Intracellular fluid- found within cells
- Interstitial fluid- found between cells
- Plasma- fluid component of blood
explain the composition of the extracellular fluid
ECF is made up of interstitial and plasma and surrounds all cells. Interstitial fluid is the fluid outside of blood vessels and plasma is the dynamic component contained within blood vessels. Their composition is almost identical other than plasma proteins and blood cells that cannot cross the blood vessel capillary wall so are only in plasma.
Define the dilution principle and state what compartments can be sampled.
It’s a method of measuring body fluid volumes. Only plasma can be sampled therefore only plasma, ECF and TBW can be measured.
What does homeostasis require in terms of systems
Requires systems to integrate to maintain optimum internal environment
List some changes that effect our internal environment and how this threatens homeostasis
External temp, access to nutrients and exercise will all impact on our body fluid composition, energy stores and body temp that threaten homeostasis
What is the major component of all 3 body fluid compartments
water- it can move freely between plasma, interstitial fluid and intracellular fluid
Of what compartment is the composition very important and why
The Extracellular fluid- as body can only survive if the composition is maintained in a state compatible with the survival of its individual cells
Explain the composition of ICF in relation to ECF
their composition is very different, particularly for ions as the cell membrane is selectively permeable and only allows certain things to cross.
What is the dynamic component of ECF and why is it called this
Plasma- because it is continuously moving around the body through blood vessels by pumping action of the heart
