introduction to body Log Flashcards
define homeostasis
physiological process by which the internal systems of the body are maintained at equilibrium (dynamic equilibrium)
Recall percentage of water in standard 70kg male
60% water therefore = 42kg of water
where are the fluid compartments in the body and the percentage of fluid in this
extracellular = 1/3 which breaks down to 20% being blood plasma and 80% being interstitial fluid. The other 2/3 of fluid is intracellular fluid
what is cell dehydration
when cells dot have enough water and leads to organism death. This is because cells will absorb water from the organs which will die.
what is cell toxicity
when cells have too much water leading to metabolic failure and eventually organism death because enzymes and proteins stop working and the cells will burst.
give 2 examples of negative feedback loops
thermoregulation and blood glucose regulation using insulin and glucagon.
describe the fundamentals of negative feedback loop
an increase or decrease away from normal, body works to restore the normal state
give 2 examples of a positive feedback loop
blood clotting cascade and the release of oxytocin during contractions before giving birth.
explain how the clotting cascade is a positive feedback loop
platelets adhere to the site of haemorrhage and release chemicals which attract more platelets which then also relate chemicals to attract more platelets. when a change results in an increased response
explain how oxytocin acts as positive feedback loop
baby head pushes against cervix, signals sent to brain which cause oxytocin to be released from the pituitary and this leads to the cervix further contracting and more oxytocin being released
what is core body temperature and when may it fluctuate
37 degrees +/- 0.5 but during ovulation body temp rises
how is body temperature controlled
TOO HOT
hypothalamus activates cooling systems eg sweating, vasodilation to decrease body temp
TOO COLD
hypothalamus detects low temp and activates heating systems e.g shivering and vasoconstriction
what happens when you become hypothermic
shivering, low pulse, drowsiness and rigid muscles
what happens when you become too hot
fever, heat stroke and heat exhaustion. hot to touch strong pule, confused and restless, dizzy
what is normal pH range of body
7.35-7.45
how is blood pH controlled
blood acidosis occurs when increased metabolism and when this happens kidneys excrete H+ and retain hco3- and lungs blow off CO2 to decrease acidity
blood ankylosis occurs and kidneys excrete hco3- and retain h+ and if you breathe into paper bag then you take up more co2 which would increase the pH of your blood (co2 is acidic)
name a blood pH buffer
carbonic acid and aluminium hydroxide is a good antacid to use
how does bulk water flow work
aquaporins are found in the membrane and allows facilitated diffusion of water across membrane. whether they are open or not depends on amount go glycerol in cell
explain osmolality
the conc of a solution expressed as osmol/L and is not dependant on temp or pressure
explain how osmolality is calculated
if there is an NaCL then this when it dissolves give Na+ and cl- which gives 2 mosmoles. If you want to find it of a whole patient then you’d have to add together all the different concentration of things in the body. ???
what is oedema and how does it happen
fluid retention when hydrostatic pressure is higher than osmotic pressure. Commonly found in ankles due to presence of plasma proteins in interstitial space or due to blocked lymph nodes
