excretion corrections

Question 1

how does a natural membrane differ from a dialysis membrane (1)

Answer 1

natural ; performs active transport/ facilitated diffusion dialysis memb cannot !

Question 2

why does peritoneal dialsysis use dextrose and a bit of water rather than lots of water ?( 2)

Answer 2

dextrose reduces water pot, prevents water from moving into tbe blood by osmosis

Question 3

why is haemodialysis fluid replaced less that peritoneal dialysis (2)

Answer 3

.fluid is constantly being replaced in haemodyalysis (1) by countercurrent flow (1)

OBVIOUS MARK: periotneal dialysis removes less waste or haemodyalysis i more efficient at removing waste

other points: haemodyalyis maintains constant conc grad whereas in peritoneal dialysis the conc grad is lower

Question 4

what parts of the nephron are located in the cortex ?

Answer 4

everything apart from loop of henel, collecting duct ( basically the outer most bit of the nephrons on the diagram1!!)

Question 5

where is glucose selectively reabsorbed into the blood capillaries ?

Answer 5

its selectively reabsorbed in the PCT!

Question 6

What is the advantage of having a long loop of henle for camels ?

Answer 6

.more sodium/chloride ions are pumped at the ascending limb to the medulla so there is a larger water potential gradient thsus more reabsorption of water down collecting duct !

Question 7

state the TYPE of drug used in body buildign

Answer 7

anabolic steroids

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Question 8

in terms of erythrocytes, amino acids, glucose and ions, explain the chasnges in concentrations of each as they travel from the blood and out of the collecting duct as urine (5)

Answer 8

.large molecuels such as erythrocytes cannot leave blood

.due to the fact that they cannot pass through the basement membrane / fenestrations therfore conc of erythrocytes in glomerular filtrate and urin are 0

.all glucose is reabsorbed from PCT therefore concerntration of blood in urine is 0 in urine

.all amino acids are reabsorbed from the PCT therefore concentration is 0 in urine

. ions are reabsorbed into blood the conc of ions in urine are increased

Question 9

discuss the ethics of kidney transplanation ? (3)

for discuss questions ;

state general consensus, advantages, disadvantages, issues and conclusion

Answer 9

general consensus:. people should have a right to choose whether to donate or not

. state advantages : donors can benefit from the money + people can donate to family memmber

state disadvantages: poor people can be exploited for their kidneys+ minors can also be exploited for their kidenys (there IS an age of consent)

general ethics: people should recieve transplants regardless of wealth and its wrong to charge patients excessively

Question 10

what occurs in the PCT?

Answer 10

. glucose and water AND SALTS reabsorbed into the blood CAPILLARIES that surround the nephron at this point

Question 11

where are the cells that detect decrease in water potential of the blood found?

AND

what cells detect the decrease in water potential of the blood ?

Answer 11

HYPOTHALAMUS

OSMORECEPTORS

Question 12

which bit of the adrnenal gland releases aldosterone ?

Answer 12

the cortex

Question 13

where does ADH act on in the kidneys?

Answer 13

acts on DCT and collecting duct

Question 14

where in the nephron are the walls impermeable ?

Answer 14

ascending limb (loop of henle)

Question 15

explain the role of the loop of henle in the production of urine ( 5)

Answer 15

the role of the loop of henle was to cause a decrease in water potential in the medulla

since in the ascending limb, active transport outwards of ions and solutes occur

.walls of the descending limb are permeable to water thus removing the water from the descending limb

and in the end water is removed from filtrate in the collecting duct!