homeostasis Flashcards
define the term homeostasis
maintaining similar (not identical) internal body conditions. also prevents the disturbance of in a system
explain the importance of maintaining constancy of the internal environment
failure to do so results in illness, disease and even pathology
give examples of internal and external change that could affect homeostasis in organisms
external= temperature change
internal = change in energy demand
what happens if compensation with homeostasis succeeds?
leads to wellness
state the 3 main mechanisms of homeostasis
- negative feedback
-feed forward
-positive feedback
describe the principles behind negative feedback systems
it is a trigger that initiates a response
that response brings homeostasis back to its normal range & removes the initial trigger
what is one characteristic of negative feedback ( does it prevent situations from happening?)
no it only acts after disturbance has happened.
what homeostasis mechanism prevents change before it happens
feed forward system
e.g in digestion your body has cells that are activated even before any food enters your mouth
what are the characteristics of feed forward mechanism ?
prevents a situation from getting worse
give example of positive feedback and example its mechanism
e.g action potential or The positive feedback mechanism of childbirth is essential for the progression of labor, as it ensures increasingly powerful contractions to facilitate the dilation of the cervix and ultimately the delivery of the baby
makes a situation worse
what percentage of human body is water?
60%
if an adult male looses 10ml of water how much does he then gain?
10ml
as your gain and losses are ALWAYS equally balanced
*(what we gain we must loose and what we loose we must gain)
list the body fluid compartments in which water is located
- intracellular fluid (fluid inside cells)
-intersititial fluid (fluid between cells - plasma fluid ( fluid component of blood)
give examples of compartments that are classified as extracellular fluids
intersitial fluid and plasma fluids
what is the biggest water compartment in the body and how much does it weigh?
intracellular fluid (ICF) 28L
what is the difference between the intersitial fluid and Plasma fluid & is there a barrier that separates the two?
there are proteins in the plasma fluid but not in intersitial fluid.
no barrier
is the membrane that separates intracellular fluid and extracellular fluid selective?
yes
what component of the extracellular fluid is known as the dynamic component
Plasma fluid is known as the dynamic component
do arteries undergo exchange (nutrients and waste products) between the ISF and Plasma fluids?
no walls are too thick
what does the total body water consist of ?
ICF, ECF(intersitial and plasma fluid)
how would you measure body fluid volumes?
use dilution principle
V= M/C or C=M/V
can only measure plasma as we only have access to that
but can indirectly measure other components
What are the dominant ions in ECF and ICF?
and what do they form?
ECF= Na and CL
ICF = K
this forms conc gradient
why is the concentration gradient between the ECF and ICF important
important for nerve and muscle function
If homeostasis in the ECF isnt working what does this mean?
explain how this can be resolved if the individual is healthy
lead to death & disrupts muscle function
kidney fixes it if ur healthy
