Excretion (the kidney) q's Flashcards
a student designed an experiment to investigate the effect of temp on the rate of glucose diffusion through dialysis tubing. State factors that would need to be controlled in this experiment
- vol of solution
- initial glucose conc
- brand of dialysis tubing
- length of dialysis tubing
describe the structural difference between alpha and beta glucose molecules
H above the ring / OH below ring on carbon 1
what can you conclude about the likley effect of sulthiame (inhibits carbonic anhydrase) on the reabsorption of sodium ions in the PCT?
- fewer H+ ions in PCT cells
- No cotransport of Na+ ions into cells
- no active transport of Na+ ions into the blood
compare the processes occuring in the proximal and distal convoluated tubules
similarities
- both use active transport
- both involve co transport
- both involve selective reabsorption
- both involve use of Na+
differences
- DCT involves use of Ca2+
- co transport in DCT involves ions only
- PCT involves ions+ moleucles
state+ explain one symptom you would expect to oberserve as a result of nephrogenic diabetets insipidus (Li entering Na Channels ; prevent cells from responding to collecting duct)
- high level of urine/ always thirsty
- fewer aquaporins in the plasma membrane of CT
explain why podocytes are usually unable to undergo mitosis
- are differenciated therefore cannot divide
- are in G0 phase of cell cycle/ resting phase
- shape is too irregular therefore cannot divide
- cytoskeleton cannot function
- if mitosis occured, it would alter no. of fenestrations
- it would alter an aspect of ultrafiltration
what features of adult stem cells can make them suitable for regeneration of tissues in the kidney?
- adult stem cells are multipotent
- differenciate to became any cell type within kidney
similarities between ultrafiltration and formation of tissue fluid
- small molecules diffuse out of the blood
- both processes occurs in capillaries
- large molecules (proteins/rbc) remain in blood
- high hydrostatic pressure in both
- many molecules (water etc) reabsorbed back into capillaries
- blood vessels become narrower to maintain hydrostatic pressure
- hydrostatic pressure greater than oncotic pressure in both
- lymphocytes can pass through in both
- both involves basement membrane
differences between ultrafiltration and the formation of tissue fluid
- filterate enters the bowmans capsule + then PCT in the kidney but tissue fluid bathes cells
- molecules that are not reabsorbed by capillaries form urine in the kidney but molecules that are not reabsorbed from tissue fluid will form lymph
- blood filtered through 3 layers in ultrafiltration by only 1 layer in formation of tissue
- knot of capillaries in ultrafiltration but a network of capillaries in formation of tissue fluid
suggest+ explain 2 characteristics of a patient that must be taken into account when using this GFR measurement to diagnose kidney damage
- age bc kidney finction declines w/ age
- gender bc men+ women have diff muscle mass
explain why the presence of protein albumin in the urine indicates kidney damage
- large protein should remain in the blood
- protein too large to cross the basement membrane
state one function of the distal convoluted tubule
regulation of ions
describe the function of the structures labelled A (something in PCT)
increase SA for reabsorption
has cotransporters for active transport of Na+
suggest why DCT lumen had high conc of urea
water is removed earlier in the nephron
explain why some foods affect urine production (bar chart)
- salted crisps+ boiled sweers reduce WP bc of high sugar content
- osmoreceptors in hypothalamus detetct change in WP in blood + cause increased release of ADH
- ADH causes production of aquaporins in collecting duct so more water reabsorbed into capillaries
- bread/milk/choco incre WP of blood
- causes reduced ADH release
describe how the endocrine + nervous system work together to increase water reabsorption from the collecting duct (endocrine system)
-hypothalamus causes release of ADH from pituitary aldosterone released from adrenal cortex
- ADH released from pituitary gland
-ADH binds to receptors of the cell membranes of collecting duct cells+ incr permeability to water (regulated by aquaporins)
- role of cAMP
describe how the endocrine+ NS work together to incr water absorption from the CT (NS)
- Hypothalamus is part of NS
- osmoreceptors in the hypothalamus
- detect a low WP in the blood
- ADH prodcues in the hypothalamus
- posterior pituitary is extension of hypothalamus
decribe how endocrine + NS work together to incr water absorption from the collecting duct (aldosterone)
- sodium ions pumped out of collecting duct cells into tissue fluid + K+ ions pumped in
- decr WP in tissue fluid
- conc grad established
- Na+ reabsorbed from the collecting duct lumen
- H20 diffuses into CT via osmosis
reason why a diuretic (drug) might be most effective at reducing a persons BP
more urine is produced
reason why a diuretic (drug) would be the most appropriate for use by a person w/ type 2 diabetes
one that does not have an affect on glucose
suggest two adv and one dis of a kidney transplant compared to dialysis
adv- doesnt require repeated dialysis ; better quality of life
dis- risks of surgery ; difficult to find organ donor
suggest a non invasive method that could be used to test for these cancers (bladder/kidney)
test urine
explain why the visible blood vessels are likely to be veins
- have valves so will bulge
- large lumen as contains large volumes of blood
- found closer to the surface skin than arteries
suggest why anabolic steriods are effective when applied to the surface of the skin
- skin has large SA for absorption
- skin has many capillaries
- steriods are lipid soluble so can cross phospholipid bilayer
- muscles are close to the skin surface so short diffusion distance
‘the IOC is succeeding in reducing the level of steriod abuse in professional sport’ evaluate this statement using the data
argument
- from 1986-1958 there was an incr in % test w/ testosterone
- correlation doesnt equal causation
- more test but more athletes competing
validity
- only a limited time was studied
- other steriod used+ not detected
- other drugs mask testosterone levels
- decr in % smaples w/ testosterone from start to end of test
- from 1988 to 1991. % samples w/ testosterone decr as test no. incr
- incr in no. of test carried over time
suggest why ‘uncertain diagnosis’ occur more often in the group of pateints aged 65+ yrs compared w/ the group below 65 yrs of age
older ppl may have complex medical problems
state the type of cells from which RBC are formed + where this type of cell is located
type of cell - stem cells
location - bone marrow
explain how the longer loop of henle is able to assist the desert kangaroo rat in preventing excessive water loss
- more Na+ and Cl- ions pumped into medulla
- builds up greater WP gradient
- allow reabsorption of more water from collecting duct
state the type of drug that can be misused in body building
anabolic steriods
explain the changes in fluid composition of blood, glomerulus filtrate, urine ( from data)
- proteins cannot leave blood / enter filtrate
- basement membrane prevents erythrocytes reaching bowmans capsule
- all glucose completely reabsorbed at the PCT
- not all ions are reabsorbed
- urea conc incr bc movement of urea into tubule
suggest + explain what a high conc of creatinine in the blood plasma indicates about kidney function
incr creatinine conc indicates reduced function bc less filtration
discuss (w/ reference from info) whether it is ethical for live donors to be used as a source of kidneys for transplantion
- ppl should have a right to choose what to do w/ their kidney
- ppl can donate a kidney to family member (adv)
- exploiting ppls poverty / minors (dis)
- ppl should recieve transplants irrespective of wealth
state precisely where the cells that detetc a decrease in the water potential of the blood plasma are found
hypothalamus
name the cells that dectect this decrease (in WP)
osmoreceptors
name the part of the adrenal gland that releases aldosterone
cortex
suggest + explain what effect the action of aldosterone will have on the secrection of ADH
- WP will decrease
- therefore ADH secretion will increase
which parts of the nephron corresponds to each of the statements in the table below:
- walls are impermeable to water
- glucose is reabsorbed into the blood
- ADH acts on the walls
- Contains podocytes
- most of the water is reabsorbed into the blood
ascending limb
proximal convoluted tubule
collecting duct
bowmans capsule
proximal convoluted tubule
explain the role of loop of henle in the production of urine
- role of loop of henle is to cause a decr in WP in medulla
- ascending limb active transport outwards of ions
- walls of descending limb permeable to water
- water removed from descending limb
- WP of tissues surrounding collecting duct is lower than fluid inside it
- water removed from urine
name the organ that produces urea
liver
suggest why a high intake of protein in the diet will be likley to result in a high conc of urea in urine
- incr intake of proteins leads to a large amount of amino acids
- excess amino acids cannot be stored
- amino acids deaminated
- large amount of ammonia enters ornithine cycle for converion of urea
- incr Blood conc of urea leads to more urea in urine
- high conc of urea in blood increases water absorption from urine
suggest what condition is indicated by the presence of gluocse in a persons urine
diabetes
state the substance that is being tested for in urine when a pregnancy test is carried out
hCG
using your knowledge of how a test stick works, suggest how the test stick in fig 2.1 can be used to indicate a positive result for LH in urine
LH binds to its complementary antibodies (anti-LH)
this antibody complex moves along test stick together w/ urine
this antibody complex binds only w/ immoblised antibodies specific to them
only control antibodies bind w/ immoblised abtibodies specific to them
binding of antibody w/ dye to its immoblised anti-antibody produced line
2 lines indicates the result
explain how glomerulus is able to perform its function
- afferent arteriole is wide than efferent arteriole
- build of hydrostatic pressure
- endothelium of capillary has fenestrations
- these allow ultrafiltration
name the specialised cells present in bowmans capsule that assist the function of glomerulus
- podocytes
suggest the effect of complete kidney failure on the compostion of the blood
if kidney cannot filter so substamces remain in blood such as will have an incr in urea, in water
explain the need for close matching of the donated kidney to the recipient
if not closely matched
- donated kidney will be recognised as foreign
- antigens on donated kidney will be different
- causing rejection by immune system
- use of immuno-suppressant drugs
describe the features of the glomerulus and bowmans capsule that allow them to perform their function effectively
- ultrafiltration
- afferent arteriole is wider than efferent arteriole
- high blood pressure in glomerulus / high hydrostatic pressure
- endothelium has gaps to prevent passage of cells
- basement membrane stops removal of large molecules
- podocytes of bowmans capsule have finger like projections
- projections ensure gaps to allow passage of substances
suggest diff in the composition of the urine of a person w nephritis when compared to the urine of a person w/ healthy kidney
- large proteins present
- blood cells present
- glucose present
- more water present
- more ions present
- more vitamins present
suggest 2 ways in which the structure of this aquaporin prevents the passage of ions
- the ions in solution are too large to passs through the channel
- shapes not compatible
- +ve charge in the channel repels the positively charged ions
explain the likely effect on the blood cells if the WP of the plasma was allowed to incr significantly
- WP outside cells would be higher than that of the blood cells
- water would enter blood cells
- blood cells will swell
name the type of monomer that makes up a moelecule of ADH + the bond that joins the monomers together
type of monomer: amino acid
name of bond: peptide
ADH doesnt stay in the blood indefinitley. suggest where ADH is removed from the blood and describe what then happends to the ADH molecule
how ADH is dealt w/ as a protein:
- in liver
- hydrolysis occurs
- deamination (amine group removed)
- ornithine cycle (formation of urea)
- amino aicds used in metablic pathway
how ADH/ urea is dealt w/ as a small molecule in kidney
- in kidney
- filtered from blood(moves from blood into nephron)
- bc small molecule
- urea not all reabsorbed / ADH not reabsorbed/ ADH present in urine
- excreted
explain how the stick detects this pregnancy hormone
- testing for human chorionic gonadotrophin / hCG
- hormone small so can pass from blood into filtrate at bownmans capsule
- immoblised antibodies on stick
- antibodies attched to dye
- hormone binds to antibody
- line become visible
comment on whether the use of steriods should be permitted in sport
- giving unfair adv
- health risks like infertility
- doesnt affect athletes natural talent
- pressure to keep up w/ rival competitors
- can train for longer
- idea that atheletes should be role models
explain how these observations changes in conc are bought about by the proximal convoluted tubule (from data)
- selective reabsoption
- of gluoce and amino acids
- direct uptake of glucose by AT
- water fellows by osmosis so conc of ions incr
suggest why it is necessary to add an anticoagulant to the blood when blood flows in machine
so that clots dont form while in the dialysis machine
siggest why no anticoagulant is added to the blood towards the end of a dialysis sessions
allowing blood to clot normally after treatment
state the process by which molecules + ions other than water will move from the blood into the dialysate
diffusion
suggest why the direction of flow of the blood and the dialysis is opposing
maintain conc gradient
name one chemical that transfers a nerve impulse from one neurone to another
acetylcholine
suggest the part of the neurone where the plasma membrane has TRA1 receptors
- presynaptic membranes
- prevents release of neurotransmitters
suugest a reason for the accumulation of high conc of NAPQI in the liver cells
- not enough glucuronide to metabolise NAPQI
