Lecture 2: Filtration And Renal Blood Flow

Question 1

What does filtration occur?

Answer 1

Glomerulus

Question 2

Filtrate enters Bowman’s capsule, which is the beginning of what?

Answer 2

PCT

Question 3

What forms the filtration membrane?

Answer 3

Capillary epithelial cells, basements membrane, and podocytes

Question 4

Rate of filtration is measured by….

Answer 4

GFR

Question 5

The best way to determine GFR is to determine clearance of molcules such as:

Answer 5

Inulin

Creatinine

Question 6

Sugar that your body cant metabolize

Answer 6

Inulin

Question 7

Byproduct of muscle metabolism

Answer 7

Creatinine

Question 8

As GFR decreases, plasma creatinine __________

Answer 8

Increases

Question 9

Small changes in creatinine mean…

Answer 9

Big changes in GFR

Question 10

What filters and what doesn’t filters?

Answer 10

Does filter: water, ions, small molecules.

Doesn’t filter: plasma proteins and solutes bound to plasma proteins (thyroid hormone or bound calcium)

Question 11

Amount of solute that entered the tubular fluid

Answer 11

Filtered load

Question 12

What can filtered load be used for?

Answer 12

To determine HOW a solute is handled in the nephron.

Because filtration and secretion adds solute to the tubular fluid while secretion removes them

SO

Excretion=filtered load + secretion - reabsorption

Question 13

If you constrict the afferent arteriole..

Answer 13

Reduce Pgc
Reduce GFR
Reduce RBF

Question 14

If you dilate the afferent arteriole….

Answer 14

Increase Pgc
Increase GFR
Increase RBF

Question 15

If you constrict the efferent arteriole…

Answer 15

Increase Pgc
Increase GFR
Decrease RBF

Question 16

If you dilate the efferent arteriole….

Answer 16

Reduce Pgc
Reduce GFR
Increase RBF

Question 17

Dilating the afferent arteriole will have what effect on GFR and RBF?

Answer 17

Increase GFR and RBF

Question 18

If a patients filtered load of K+ is 10mg/min and excretion rate is 1mg/min, how is K handled in the nephron? (select all that apply).

Answer 18

Filtered, reabsorbed, and secreted

Question 19

RBF is calculated by clearance of what?

Answer 19

PAH

Question 20

Kidney is able to control its own blood flow in response to:

Answer 20

Change in pressure

Autoregulation

Question 21

At a high blood pressure, will you have more or less urine?

Answer 21

More

Question 22

What’re the 3 mechanisms of autoregulation in the kidney?

Answer 22

1. Myogenic response, in smooth muscle
2. Tubuloglomerular feedback, in the nephron
3. RAAS system, due to release of renin

Question 23

What is the myogenic response of the kidney?

Answer 23

Smooth muscles stretch, and it actively contracts against that force.

Maintains constant flow by changing resistance

Question 24

What is the tubuglomerular feedback?

Answer 24

Nephron is able to sense GFR and regulate RBF

high sodium in tubular fluid, means a high GFR and BP

Occurs at JGA (macular densa and juxtaglomerular cells)

Question 25

If GFR is high, NaCl will be filtered and taken up by the: Which will result in what?

Answer 25

Macula densa More sodium in the tubular fluid and more activity of the Na/K ATPase, which will produce more adenosine. Also lowers Renin production

Question 26

What does adenosine do??

Answer 26

Binds to smooth muscle cells and causes constriction of afferent arteriole Which then reduces GFR and RBF

Question 27

Renin is released under what 3 conditions ?

Answer 27

1. Low arterial pressure 2. Tubular sodium decreases 3. Effective circulating volume decreases

Question 28

Renin will increase levels of what?

Answer 28

AngII and aldosterone

Question 29

Low levels of AngII...

Answer 29

Constrict efferent arterioles and increase GFR

Question 30

What are high levels of AngII damaging?

Answer 30

It constricts both afferent and efferent arterioles

Question 31

Aldosterone increases what?

Answer 31

Na and H2O retention (increases BV)

Question 32

In which arteriole would the myogenic/autoregulatory response be most prominent?

Answer 32

Afferent

Question 33

Myogenic and Macular Densa work most on the __________ arteriole

Answer 33

AFFERENT

Question 34

AngII acts preferentially on the ____________ arteriole

Answer 34

EFFERENT

Question 35

When and what do Norepinephrine and Epinephrine do to the kidney?

Answer 35

Constrict both afferent and efferent, only in times of high SNS stimulation, like a massive hemorrhage.

Question 36

What does Nitric Oxide do to the kidney?

Answer 36

It's a vasodilator. | Counteracts AngII on afferent Doesn't make it to the efferent

Question 37

What do prostaglandins do to the kidney?

Answer 37

They're vasodilators. Counteracts AngII on afferents

Question 38

NSAIDS block production of what vasodilators? | What could this lead to?

Answer 38

Prostaglandins. Could lead to kidney ischemia in already hypotensive patients

Question 39

GFR/RBF Regulation Response to hemorrhage? response to massive MI? Response to a high dose of ACE-1? Response to being scared?

Answer 39

Last slide of lecture 2, draw it out