Lect 3 - Block 3 - Glomerular Filtration

Question 1

Filtered load is _________ x __________
It is the quantity of a compound that enters Bowman’s capsule each minute

Answer 1

GFR x filtrate concentration

Question 2

Blood flow through kidney:

Answer 2

Renal artery, arterial branches, interlobular artery, afferent arteriole, glomerular capillary, efferent arteriole, peritubular capillary, venous branches, renal vein

Question 3

Filtration fraction

Answer 3

GFR/renal plasma flow = filtration fraction

Percent of plasma which is filtered by the renal glomerulus and enters Bowman’s capsule
Usually about 20% of total RPF

Question 4

Tubular system order of flow

Answer 4

Bowman’s capsule, proximal tubule, loop of Henle (thin descending, thin ascending, thick ascending), distal tubule, cortical collecting duct, medullary collecting duct, renal papilla, ureter, bladder, urethra

2 tipos de néfrons

Juxtamedullary nephrons
Cortical nephrons

Question 5

Ultrafiltrate first enters where?

Answer 5

Bowman’s capsule

Question 6

Glomerular capillaries get what percent of cardiac output?

Answer 6

20-25%
1200-1300mL/min

Question 7

2 capillary beds of the kidney

Answer 7

Glomerular: 1300mL/min
Peritubular capillaries
Cortex: 1000mL/min
Outer medulla: 240mL/min
Vasa recta to inner medulla: 60mL/min

Cortex and outer medulla get most do the peritubular capillary blood flow

Question 8

Plasma is what percent of blood?

Answer 8

55% (other 45% are RBC’s)

Question 9

Renal Plasma Flow (RPF) =

Answer 9

RBF(1-hematocrit) = RBF
600-700mL/min (both kidneys)

Question 10

GFR is normally

Answer 10

125mL/min (120-140 - both kidneys)

Question 11

Urine production rate is normally about _______, and ranges from _____ to _____

Answer 11

1mL/min, ranges from 0.4 to 20mL/min

Question 12

Filtration fraction is ______ if preglomerular resistance changes
Filtration fraction is ______ if postglomerular resistance changes

Answer 12

constant
altered

Question 13

Kidneys use autoregulation for blood pressure. The normal BP range is from ___to___mmHg, and changes in BP within this range (do/don’t) alter renal blood flow or GFR.

Answer 13

80-150mmHg
changes in this range don’t alter renal blood flow or GFR

Question 14

Kidney blood flow control - autoregulation
1.
2.
3.

Answer 14

1. Tubuloglomerular feedback
2. Myogenic
3. Prostaglandins

Question 15

Kidneys shut down at blood pressures less than ____mmHg

Answer 15

50mmHg

Question 16

Blood flow (is/isn’t) controlled by metabolism in kidneys

Answer 16

isn’t

Question 17

Even though GFR doesn’t change with blood pressure, the rate of urine formation is directly tied to arterial blood pressure. This is called ______ ________, where increase in arterial pressure causes an increase in the rate of urine production

Answer 17

pressure diuresis

Question 18

Sympathetic innervation of kidneys
1.
2.
3.

Answer 18

1. mostly afferent arterioles, some efferent
2. Justaglomerular cells (renin secretion)
3. Tubule (Na+ reabsorption)

Question 19

Hydrostatic pressure from across glomerular capillary starts at ____ and ends at _____

Answer 19

50, 40

Question 20

colloid osmotic pressure in glomerular capillary changes from ____ to ____

Answer 20

25, 30

Question 21

Hydrostatic pressure of Bowman’s capsule is ____

Answer 21

10mmHg

Question 22

Net filtration pressure across glomerular capillary is _____

Answer 22

10mmHg outward (15 at afferent arteriole side, 0 at efferent arteriole side)

Question 23

Filtration is dependent on 5 things

Answer 23

1. permeability
2. capillary hydrostatic pressure
3. filtrate oncotic pressure
4. plasma oncotic pressure
5. filtrate hydrostatic pressure
   (filtrate oncotic pressure is normally 0, because large oncotic proteins are not filtered)

pressao efetiva de ultrafiltracao=peuf

Question 24

Oncotic pressure due to presence of proteins in plasma (increases/decreases) as fluid flows through the glomerular capillaries

Answer 24

Increases

Question 25

Afferent arteriole is changed by \_\_\_\_\_\_\_\_

Answer 25

sympathetics

Question 26

Efferent arteriole is changed by \_\_\_\_\_\_\_\_

Answer 26

angiotensin II tubuloglomerular feedback

Question 27

Protein oncotic pressure is changed by \_\_\_\_\_\_\_

Answer 27

plasma protein concentration barrier integrity

Question 28

Renal blood flow: afferent constriction causes \_\_\_RBF, \_\_\_GFR, \_\_\_Peri Reabs

Answer 28

decrease RBF, decrease GFR, increase Peri Reabs

Question 29

Renal blood flow: efferent constriction causes \_\_\_RBF, \_\_\_GFR, \_\_\_Peri Reabs

Answer 29

decrease RBF, increase GFR, increase Peri Reabs

Question 30

Renal blood flow: afferent dilation causes \_\_\_RBF, \_\_\_GFR, \_\_\_Peri Reabs

Answer 30

increase RBF, increase GFR, decrease Peri Reabs

Question 31

Renal blood flow: efferent dilation causes \_\_\_RBF, \_\_\_GFR, \_\_\_Peri Reabs

Answer 31

increase RBF, decrease GFR, decrease Peri Reabs

Question 32

3 layers filtrate passes through from glomerular capillaries to Bowman's capsule

Answer 32

barreira de filtracao 1. Capillary endo (fenestrated), keeps RBC's out ENDOTELIO 2. Basement membrane, has a "-" charge, keeps proteins out MBG 3. Bowman's capsule epi. small holes that do more filtering of big particles=estruturas podocitarias resitencia por tamanho e carga eletronegativa

Question 33

3 things that are freely filtered

Answer 33

H2O, NaCl, Glucose

Question 34

Inulin is used to measure _____ and is filtered at about 90%

Answer 34

GFR

Question 35

\_\_\_\_ charged particles are easier to filter through the basement membrane into Bowman's capsule

Answer 35

Positively

Question 36

The loss of negative charge in the basement membrane in the kidney is a consequence of this long-term disease.

Answer 36

Diabetes, due to glycosylation of the basement membrane proteins

Question 37

The loss of negative charge in the basement membrane in the kidney is a consequence of this infection.

Answer 37

Post streptococcal glomerulonephritis, where antibodies created in response to strep infection attack the glomerular basement membrane

Question 38

GFR is maintained even though the number of nephrons is lost in chronic kidney disease. This is because the remaining nephrons...

Answer 38

have a compensatory increase in glomerular filtration rate

Question 39

The body can tolerate a loss of 1/2 of the nephrons and still maintain \_\_\_\_% of GFR

Answer 39

90%

Question 40

Administering an ACE inhibitor will cause a(an) ____ in GFR and a _____ in filtration fraction. This is because the ____ arteriole is dilated

Answer 40

decrease, no change, efferent

Question 41

During malignant hypertension, administering an ace inhibitor will __________ GFR. This is due to dilation of the ________ arteriole

Answer 41

Decrease, efferent