Renal II: Glomerular Filtration

Question 1

filtration

Answer 1

blood plasma filtered into capsular space

Question 2

reabsorption

Answer 2

water and useful substances are reabsorbed into blood from tubular fluid

Question 3

secretion

Answer 3

certain wastes are removed from blood by secretion into tubular fluid (soon to be urine)

Question 4

excretion

Answer 4

the process of eliminating waste products from the body

Question 5

rate of excretion

Answer 5

rate of glomerular filtration + rate of secretion - rate of reabsorption

Question 6

what are the three layers of the filtration barrier of glomerular filtration?

Answer 6

fenestrated endothelium, basement membrane, podocytes

Question 7

What does the fenestrated endothelium of the glomerular capsule filter and allow to pass through?

Answer 7

filters blood cells, allows components of blood plasma to pass through

Question 8

What does the basement membrane of the glomerular capsule filter?

Answer 8

large proteins, negatively charged substances

Question 9

What do the podocytes of the glomerular capsule filter?

Answer 9

medium sized proteins

Question 10

NFP =

Answer 10

GBHP - CHP - BCOP

Question 11

what does GBHP do

Answer 11

forces blood into glomerulus

Question 12

What is GFR?

Answer 12

glomerular filtration rate
Amount of filtrate formed in all renal corpuscles of both kidneys per minute

Question 13

What happens if GFR is too high?

Answer 13

Useful substances are lot due to the blood passing through too quickly
(everything goes through)

Question 14

What happens if GFR is too low?

Answer 14

Sufficient waste products may not be removed

Question 15

Why is a constant GFR required to maintain homeostasis?

Answer 15

to ensure everything that needs reabsorbed gets reabsorbed (maintain homeostasis of blood, BP, blood volume)

Question 16

What does NFP depend most heavily on?

Answer 16

GBHP

Question 17

At what level does GBHP stop filtration?

Answer 17

less than 45 mmHg
(MAP 80-100 mmHg does NOT stop filtration)

Question 18

What are the 3 mechanisms for GFR regulation?

Answer 18

auto
neural
hormonal

Question 19

What cells are at the top of the ascending limb of the loop of Henle?

Answer 19

Macula densa cells

Question 20

What cells line the afferent arteriole?

Answer 20

juxtaglomerular cells

Question 21

What are mesangial cells?

Answer 21

contractile cells associated with the capillaries

Question 22

What two mechanisms play a role in autoregulation of GFR?

Answer 22

myogenic mechanism and tubuloglomerular feedback

Question 23

Which mechanism of autoregulation of GFR is faster?

Answer 23

myogenic mechanism

Question 24

What causes the myogenic mechanism of autoregulation of GFR?

Answer 24

systemic increases in blood pressure stretching the afferent arteriole

Question 25

What is the effect of the myogenic autoregulation of GFR?

Answer 25

smooth muscle contraction reduces the diameter of the afferent arteriole which returns the GFR to its previous levels in seconds

Question 26

What causes the tubuloglomerular feedback of autoregulation of GFR?

Answer 26

elevated systemic BP raises the GFR so that fluid flows too rapidly through renal tubule Na+, Cl-, and water are not reabsorbed so there is an increase in them

Question 27

What cells detect the increased levels of Na+ and Cl- causing the tubuloglomerular feedback of autoregulation of GFR?

Answer 27

macula densa cells in the ascending limb of the loop of henle

Question 28

What are the effects of tubuloglomerular feedback of autoregulation of GFR?

Answer 28

inhibits release of NO (a vasodilator) from juxtaglomerular apparatus afferent arterioles constrict, reducing GFR

Question 29

Does neural regulation lower or raise GFR?

Answer 29

lower

Question 30

What happens during neural regulation of GFR?

Answer 30

Blood vessels of the kidney have sympathetic fibers that cause vasoconstriction of afferent arterioles caused by norepinephrine release

Question 31

What neurotransmitter is used for vasoconstriction of afferent arterioles in neural regulation of GFR?

Answer 31

norepinephrine

Question 32

Does autoregulation or neural regulation of GFR take precedent?

Answer 32

neural regulation overrides renal autoregulation

Question 33

What arterioles undergo vasoconstriction with moderate sympathetic stimulation during neural regulation of GFR?

Answer 33

both afferent and efferent arterioles

Question 34

When does extreme sympathetic stimulation occur?

Answer 34

During exercise or hemorrhage

Question 35

What occurs when extreme sympathetic stimulation for neural regulation of GFR happens?

Answer 35

vasoconstriction of afferent arterioles GFR decreases substantially lowers urine output to maintain blood volume permits greater blood flow to other tissues (muscle)

Question 36

What two hormones contribute to the regulation of GFR?

Answer 36

Atrial Natriuretic Peptide (ANP) and Angiotensin II

Question 37

What effect does atrial natriuretic peptide have on GFR?

Answer 37

ANP increases GFR

Question 38

What triggers the hormonal regulation release of atrial natriuretic peptide?

Answer 38

High blood volume causes atrial stretching releasing ANP from the heart

Question 39

How does atrial natriuretic peptide increase GFR?

Answer 39

ANP relaxes glomerular mesangial cells, increasing glomerular capillary surface area and increasing GFR

Question 40

Does angiotensin II increase or reduce GFR?

Answer 40

reduce GFR