introduction to body Log

Question 1

define homeostasis

Answer 1

physiological process by which the internal systems of the body are maintained at equilibrium (dynamic equilibrium)

Question 2

Recall percentage of water in standard 70kg male

Answer 2

60% water therefore = 42kg of water

Question 3

where are the fluid compartments in the body and the percentage of fluid in this

Answer 3

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

Question 4

what is cell dehydration

Answer 4

when cells dot have enough water and leads to organism death. This is because cells will absorb water from the organs which will die.

Question 5

what is cell toxicity

Answer 5

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.

Question 6

give 2 examples of negative feedback loops

Answer 6

thermoregulation and blood glucose regulation using insulin and glucagon.

Question 7

describe the fundamentals of negative feedback loop

Answer 7

an increase or decrease away from normal, body works to restore the normal state

Question 8

give 2 examples of a positive feedback loop

Answer 8

blood clotting cascade and the release of oxytocin during contractions before giving birth.

Question 9

explain how the clotting cascade is a positive feedback loop

Answer 9

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

Question 10

explain how oxytocin acts as positive feedback loop

Answer 10

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

Question 11

what is core body temperature and when may it fluctuate

Answer 11

37 degrees +/- 0.5 but during ovulation body temp rises

Question 12

how is body temperature controlled

Answer 12

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

Question 13

what happens when you become hypothermic

Answer 13

shivering, low pulse, drowsiness and rigid muscles

Question 14

what happens when you become too hot

Answer 14

fever, heat stroke and heat exhaustion. hot to touch strong pule, confused and restless, dizzy

Question 15

what is normal pH range of body

Answer 15

7.35-7.45

Question 16

how is blood pH controlled

Answer 16

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)

Question 17

name a blood pH buffer

Answer 17

carbonic acid and aluminium hydroxide is a good antacid to use

Question 18

how does bulk water flow work

Answer 18

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

Question 19

explain osmolality

Answer 19

the conc of a solution expressed as osmol/L and is not dependant on temp or pressure

Question 20

explain how osmolality is calculated

Answer 20

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. ???

Question 21

what is oedema and how does it happen

Answer 21

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