Filtration

Question 1

what causes high hydrostatic pressure in the glomerulus

Answer 1

a wide afferent arteriole feeding the glomerulus and a narrow efferent arteriole leaving it

Question 2

what is the effect of the wide afferent and narrow efferent called

Answer 2

the bottleneck effect

Question 3

the bottleneck effect causes what to happen to the plasma

Answer 3

it is forced into Bowman’s Capsule

Question 4

what kind of things cannot leave the glomerulus

Answer 4

cells and most proteins

Question 5

what happens to the things that cannot pass through the glomerulus

Answer 5

they enter the efferent arteriole and go back to the blood

Question 6

name the three filtration barriers that do not allow these materials through the glomerulus

Answer 6

1. fenestrated capillaries
2. basal lamina
3. podocytes

Question 7

describe fenestrated capillaries

Answer 7

leaky; does not allow any type of blood cell or protein to pass through

Question 8

where are mesangial cells found and what can they do

Answer 8

found between and around the capillaries and can contract to influence GFR

Question 9

what is the basal lamina

Answer 9

extracellular matrix that acts as a course sieve

Question 10

what are podocytes and what do they do

Answer 10

the cells of Bowman’s Capsule and they wrap around the glomerular capillaries to create filtration slits

Question 11

what can widen filtration slits

Answer 11

infection, hypertension, late term pregnancy, extreme exercise

Question 12

define GFR (glomerular filtration rate)

Answer 12

the volume of fluid that enters Bowman’s Capsule over time 125ml/min

Question 13

what is the purpose of regulating GFR

Answer 13

to maintain 125ml/min despite changes in BP

Question 14

in the myogenic response _____________ in the ________ detect BP and influence diameter of the arterioles (mostly which one?)

Answer 14

1. Stretch receptors
2. glomerulus
3. mostly the afferent arteriole

Question 15

in the event of high BP, the myogenic response will be what

what is the less common response

Answer 15

constrict the afferent arteriole to decrease the bottleneck effect
less common is to vasodilate the efferent arteriole

Question 16

in the event of mild-moderate hypotension what will the myogenic response be

Answer 16

1. vasodilate afferent arteriole

2. vasoconstrict the efferent arteriole

Question 17

what would be the response in extreme hypotension

Answer 17

it is ok to have low GFR to keep as much volume as possible in the blood and not in the kidneys

Question 18

tubuloglomerular response involves the ___________ apparatus

Answer 18

juxtaglomerular

Question 19

the juxtaglomerular apparatus is the association of the ________________ and ________ arteriole

Answer 19

ascending limb and the afferent arteriole

Question 20

where are macula densa cells found and what are their functions

Answer 20

cells on the ascending limb; they monitor the amount of NaCl moving through and thus indirectly monitor GFR

Question 21

what happens when the macula densa cells dectect high levels of NaCl

Answer 21

it indirectly indicates high GFR so they release a paracrine to target granular cells (afferent arteriole) to vasoconstrict the afferent arteriole

Question 22

________ neurons relate both afferent and efferent arterioles to _______ the bottleneck effect and lower GFR during extreme __________
name examples of these situations

Answer 22

1. sympathetic
2. decrease
3. hypotension
   examples: dehydration and hemorrhaging

Question 23

what are the two chemical signaling molecules we talked about for GFR regulation

Answer 23

1. angiotensin II (vasoconstriction)

2. prostaglandins (vasodilation)