B12 - Homeostasis in Action Flashcards
adaptations of polar bears in terms of temperature
layer of fur - insulates and reduces heat loss by radiation
adaptations of a seal in terms of temperature
blubber - insulates and reduces heat loss by radiation
adaptations of an elephant in terms of temperature
large surface area and thinner skin to raise heat loss
homeostasis
keeping conditions in the body at a set point
constant body temperature
37 degrees
physical ways the body can gain/lose heat
*shivering
* sweating
* vasodilation
* vasoconstriction
vasodilation
widening of blood vessels due to the relaxation of the blood vessels’ walls
vasoconstriction
the narrowing of blood vessels by small muscles in their walls
what do capillaries do to control body temperature
control blood flow to the skin
how does sweat work
cools the body as it loses heat through evapouration of water molecules
ways water is gained
- food and drink
- metabolism
ways water is lost
- urine
- feces
- skin
- lungs
dehydration caused by
hypertonic solution - blood has lower water concentration
what happens if you eat too much protein
- broken down into amino acids
- amino acids converted into fats and carbohydrates (deamination)
- ammonia produced as waste - toxic so converted into urea
- urea also toxic and can lead to extensive damage to cells - removed from the body in the kidney
urine
solution made by the kidney fro urea and water
structure of urinary system
- liver - produces urea
- vena cava, aorta
- renal artery - brings blood containing urea and other substances in solution to the kidney
- ureter - tube that urine passes from kidney to bladder
- urethra - tube that urine passes through to leave the body
- renal vein - carries blood away from the kidney after the removal of urea and other substances from the blood
- diaphragm
ultrafiltration
substances are filtered out of the blood - including water, glucose, urea - NOT protein and blood cells - too large
reabsorption
useful substances are reabsorbed back into the blood - all glucose, some water, some ions
adaptations of the kidney nephron for effective reabsorbtion
many microvilli containing many mitochondria for active transport
what happens to urine on a hot day
darker, stronger scent
what happens to urine on a cool day
paler, less scent
what happens to the urine when a lot of salt is ingested
contains more ions
what happens to the urine if you have diabetes
contains more glucose
what happens to the urine if you drink more water
paler, less scent
dialysis
procedure to remove waste products and excess fluid from the blood when the kidneys stop working properly
when will you need a kidney transplant
if both of your kidneys fail - you can live with only one kidney
advantages of a kidney transplant
- lasts many years
- cheaper than dialysis over a long period of time
- can live a normal life afterwards
disadvantages of a kidney transplant
- large risk of infection
- very few tissue matches
- need to take immunosuppressant drugs
advantages of dialysis
- no major surgery needed
- easy access, no donor needed
disadvantages of dialysis
- low protein diet needed
- cannot lead a normal life afterwards
- start to feel ill before next treatment is due
- spend frequent long periods in the hospital
