CHAPTER 12 Flashcards
where is temperature controlled
thermoregulatory centre
where is the thermoregulatory centre
the hypothalamus brain
how does the thermoregulatory centre detect changes
receptors test temperature of blood in brain receptors in skin
how does the body cool down
sweat vasodilation
what is vasodilation
the blood vessels near the skin dilate so more blood is exposed to the cool air and cools down
how does sweat cold you down
it evaporates from the skin takin heat with it
how does the body warm up
vasoconstriction
shiver
hairs stand on end
how does hair standing on end warm you up
it catches and traps an insulating layer of air
how does shivering warm you up
the movement of skeletal system means for respiration (an exothermic process)this heats up the body
what is vasoconstriction
blood vessels constrict near the skin so less blood is available to the cold air
why should the body not get too hot
dentures enzymes
what are the two main waste products
carbon dioxide and urea
when is carbon dioxide produced
carbon dioxide
why is carbon dioxide so dangerous
when it dissolves, it produces acid which effects the enzymes in cells
how do you get rid of CO2
diffuses from cells into blood stream diffuses from blood stream into lungs this air is exhaled
how is urea produced
breakdown of excess amino acids turns into ammonia which turns into urea
where is urea produced
liver
why is urea dangerous
it is poisonous to cells
how do you get rid of urea
kidneys filter it out
3 ways in which you lose water from body
exhaling
sweat
urine
function of kidneys
filters substances like urea from the blood
maintains a healthy water level
how do the kidneys conserve water
you produce very concentrated urine with not that much water
how do kidneys work
filter blood substances like urea are small enough to pass through membrane to be excreted substances like glucose are too big selectively absorbs molecules like water to be reabsorbed if you need them
what is selective reabsorption
the amount of water that is reabsorbed into your body depends on the circumstances eg dehydrated
what does ADH stand for
anti diuretic hormone
where does ADH come from
pituitary gland in brain
how does ADH affect water concentration in blood
it tells the kidneys how much water to converse
if the water conc is too high what happens
less ADH so less water reabsorbed
if water conc is too low what happens
more ADH so more water reabsorbed
two options of treating kidney failure
dialysis
transplant
how does a dialysis machine work
blood passes through dialysis fluid
toxins absorbed into fluid
fluid is cleaned and rid of toxins
importance of a partially permeable membrane in dialysis
allows small particles like urea through the blocks useful bigger ones like glucose
importance of dialysis fluid having same concentration of minerals as blood
so the minerals don’t cross into the fluid by diffusion
why should the dialysis fluid contain no urea
steep concentration gradient - effective diffusion of urea
why is kidney failure life threatening
build up of urea
why do people with kidney failure have to control what they eat
their kidneys cant filter substances like salt and protein out
what process does dialysis depend on
diffusion
why is it important that dialysis fluid is circulate
urea will build up in one place so doesn’t diffuse out of blood as same concentration
what is the main problem with kidney transplant
rejection
why are donated kidneys often rejected
the antigens on the surface of the new kidney will be different to those of recipient so the immune system seed the kidney as a pathogen and attacks it
what drugs are used to stop rejection
immunosuppressants
why are kidney transplant from living family members often better than transplants from unrelated dead donors
kidney hasn’t began to shut own -higher chance of success
family members = closer tissue types
advantages of kidney transplants 3
no dialysis machine
can live normal life
cheaper long term
disadvantages of kidney transplants 4
rejection
immunosuppressants
only last 9 years
waiting list
advantages of dialysis 4
immediate treatment
no surgery
no threat of rejection
no immunosuppressants
disadvantages of dialysis 4`
longterm more expensive
special diet
regular time consuming session
can cause long term damage
how and where is water made
respiration of all body cells
how and where is co2 made
respiration all body cells
why do you urinate more in winter
in summer you can sweat out excess water
what would urine look like in a cold day where you have drank a lot
pale
less concentrated - more water to dilute it
side effect of dialysis
no way of fighting other infections
where are the two types of temperature sensors found
skin and brain
what vessel enters kidney
renal artery
what vessel leaves kidney
renal vein
3 ways in which you can gain water
respiration
eating
drinking
4 ways in which water can leave body
faeces
breathing
sweating
urinating
how does a healthy kidney produce urine
blood passes into kidney flows through membrane (blood cells are too big to cross) all of glucose reabsorbed by active transport and diffusion
selective absorption of water and ions releases urea in urine
