renal

Question 1

intracellular fluid

Answer 1

all fluid in cells, 2/3 total body fluid, has water, ions, proteins and enzymes

Question 2

extracellular fluid

Answer 2

interstitial fluid (holds cells in place), plasma and trans-cellular fluids

Question 3

difference between interstitial fluid and plasma

Answer 3

plasma has more proteins than interstitial fluid

Question 4

forces that move water

Answer 4

hydrostatic pressure and colloid osmotic pressure

Question 5

hydrostatic pressure

Answer 5

force from a fluid against a wall, causes movement of fluid between different compartments

Question 6

colloid osmotic pressure

Answer 6

relies on selectively permeable membranes, small ions moving

Question 7

osmolality

Answer 7

conc of substance in 1L solvent (water) measured in mosmoles / Kg

Question 8

renal cortex

Answer 8

outermost ring of the kidney, start of the urine making

Question 9

renal medulla

Answer 9

inner region of kidney, loops of nephrons drop down into it

Question 10

how many nephrons in a kidney on average

Answer 10

1.5million

Question 11

the juxtoglomerular apparatus

Answer 11

afferent arteriole brings blood to glomerulus, HP forces fluid through bowmans capsule

Question 12

what do macula densa cells dp

Answer 12

sense DCT flow and release factors that affect afferent arteriole diameter

Question 13

main components of Juxtaglomerular apparatus

Answer 13

1. macula densa cells
2. granular cells
3. mesangial cells

Question 14

granular cells

Answer 14

respond to macula densa cells and then signal to vasoconstrict/dilate

Question 15

what is the glomerular filtration rate dependent on

Answer 15

1. capillary permeability
2. HP in capillaries
3. HP in tubules
4. osmotic pressure of plasma and tubular filtrate

Question 16

BP in a capillary compared to bowmans capsule

Answer 16

bowmans capsule is lower

Question 17

GFR equation

Answer 17

GFR = Kf (Pcap - Pbc - Pi cap)

Question 18

what happens to GFR if there is afferent vasoconstriction

Answer 18

GFR decreases

Question 19

what happens in the PCT

Answer 19

reabsorption of glucose, bicarbonate and Na+, Na+ sets up gradient so water is reabsorbed. Secretion of H+ ions so there can be bicarbonate reabsorption

Question 20

what happens in loop of henle

Answer 20

water reabsorption by osmosis in descending limb, ascending limb impermeable to water, reabsorption of salts

Question 21

what happens in DCT

Answer 21

Na+ actively reabsorbed

Question 22

what is the countercurrent multiplier

Answer 22

by reabsorbing NaCl in ascending limbs the filtrate becomes more concentrated which therefore drives the water to be reabsorbed.

Question 23

where is most of the Na+ reabsorbed

Answer 23

PCT (60-70%)

Question 24

hormonal control of the kidney - Renin-angiotensin-aldoserone system (RAAS)

Answer 24

regulates fluid balance, stage 1: release renin (enzyme) from granular cells, stage 2: release of ACE, stage 3: angiotensin 2 exerts actions on body

Question 25

what is renin released in response to

Answer 25

decrease in perfusion pressure, increase in SNS drive, decrease in Na+ conc at DCT

Question 26

what does angiotensin converting enzyme (ACE) do

Answer 26

converts angiotensin 1 to 2 by cleaving

Question 27

what does renin do

Answer 27

convert angiontensinogen into angiotensin 1

Question 28

what does angiotensin 2 effect

Answer 28

adrenal gland, kidneys and vasculature

Question 29

what do renal baroreceptors do?

Answer 29

decrease renal perfusion, increasing renin release

Question 30

what do catecholamines do

Answer 30

beta-adrenoreceptor stimulation leads to renin release

Question 31

what is aldosterone

Answer 31

steroid hormone from zona glomerulosa

Question 32

what are the consequences of aldosterone

Answer 32

Na+ retention, K+ loss, H+ loss

Question 33

hormonal control of the kidney - ADH

Answer 33

synthesised in hypothalamus, 2 main receptors are osmoreceptors and baroreceptors

Question 34

what does ADH do

Answer 34

makes urine more concentrated, pulls water back into the body. It causes vasoconstriction which increases arterial pressure

Question 35

where does ADH act and how

Answer 35

late part of DCT and in collecting duct, increases aquaporins

Question 36

hormonal control of the kidney - ANP

Answer 36

opposite of RAAS, inhibits renin, causes Na+ and water loss and increases GFR. Acts to reduce plasma volume

Question 37

what diuretics work mainly work in PCT

Answer 37

osmotic diuretics and carbonic anhydrase inhibitors

Question 38

what do diuretics do

Answer 38

trap ions etc to increase urine volume (diuresis)

Question 39

osmotic diuretics

Answer 39

alter osmolarity of plasma, suck water into tubule. issue is it doesn't block sodium reabsorption so water can be reabsorbed in DCT

Question 40

Mannitol

Answer 40

osmotic diuretic for when there is a build up of volume in brain or eye

Question 41

carbonic anhydrase inhibitors

Answer 41

in PCT, carbonic anhydrase is inhibited. stops the absorption of bicarbonate back into the body by blocking the conversion of carbonic acid into water and CO2. water and Na+ trapped in tubular fluid

Question 42

why are carbonic anhydrase inhibitors not great

Answer 42

the Na+ they trap in the PCT causes an increased delivery to the macula densa cells so there is a reduced GFR

Question 43

what are carbonic anhydrase inhibitors used for

Answer 43

glaucoma - ocular swelling, heart failure and altitude sickness

Question 44

Acetazolamide

Answer 44

carbonic anhydrase inhibitor, inhibits reabsorption of bicarbonate, is a weak diuretic and is associated with metabolic acidosis

Question 45

what are loop diuretics

Answer 45

act on ascending limb to block Na+/ K+ and 2Cl- symporter. 1/4 of the Na+ is trapped in tubules and therefore water follows.

Question 46

what do loop diuretics treat

Answer 46

pulmonary oedema

Question 47

Furosemide

Answer 47

loop diuretic used to treat chronic heart failure and renal failure

Question 48

What are thiazides

Answer 48

DCT diuretics, rely on good GFR, block Na+ and Cl- reabsorption at DCT

Question 49

Bendroflumethiazide

Answer 49

moderately powerful diuretic, traps Na+ in tubular fluid, effective as a hypotension treatment and for heart failure

Question 50

Potassium sparing diuretics

Answer 50

dont act on Na+ pump, block Na+ channels and less H+ and K+ are exchanged and therefore less K+ and H+ lost compared to other diuretics

Question 51

spironolactone

Answer 51

potassium sparing diuretics, blocks effects of aldosterone