Kidney Function, Glomerular Filtration, Pt Reabsorption

Front 1

What is the function of the nephron?

Back 1

To filter blood which then passes as fluid into a series of tubules.

Front 2

Tubules reabsorb most of the constituents of the fluid remaining after blood is filtered to produce what? Where is this sent?

Back 2

Urine, which is passed into the renal pelvis.

Front 3

T or F: The renal artery receives 25% of cardiac output.

Back 3

True.

Front 4

The renal artery takes blood to afferent arterioles. How so?

Back 4

Via interbolar and arcuate arteries.

Front 5

What are the 2 types of nephrons?

Back 5

1) Cortical nephron
-glomeruli originate in outer section of cortex and loop of Henle descends into the outer medulla
2) Juxtamedullary nephron
-glomeruli originate in the inner cortex and loop of Henle descends into the inner medulla.

Front 6

Which of the 2 types of nephrons plays a central role in production of concentrated urine?

Back 6

Juxtamedullary.

Front 7

What surrounds the glomerulus?

Back 7

Bowman's capsule.

Front 8

Of which of the following 4 items do fenestrated capillaries allow filttration of into Bowman's capsule? Plasma, blood cells, platelets, and dissolved solutes.

Back 8

Plasma & dissolved solutes

Front 9

What are the 3 barries plasma passes through during glomerular filtration?

Back 9

1) Capillary fenestrations
2) Glomerular basement membrane
3) Inner layer of Bowman's capsule consisting of podocytes

Front 10

Podocytes wrap around capillaries with thousands of cytoplasmic extensions know as ______. (Slits between these extensions act as a barrier during glomerular filtration.)

Back 10

Pedicels.

Front 11

What is the fluid entering Bowman's capsule known as? What does this fluid consists of?

Back 11

Filtrate; consists of plasma and a small amount of plasma protein (albumin)

Front 12

T or F: Glomerular Filtration Rate (GFR) is the volume of filtrate produced by both kidneys per day.

Back 12

False. Glomerular Filtration Rate (GFR) is the volume of filtrate produced by both kidneys per minute.

Front 13

T or F: The total blood volume (5.5L) is filtered every hour.

Back 13

False. The total blood volume is filtered every 40 minutes.

Front 14

T or F: Vasoconstriction causes an increase in GFR.

Back 14

False: Vasoconstriction causes a reduction in GFR. Vasodilation causes an increase in GFR.
(more blood = more filtration)

Front 15

T or F: The kidneys maintain a constant GFR regardless of changes in MAP.

Back 15

True

Front 16

Explain the myogenic response of the afferent arterioles.

Back 16

BP increases -->reflex constriction of a.a.

BP decreases--> reflex dilation of afferent arterioles

Front 17

T or F: The tuboglomerular feedback system involves regulation of NaCl concentration levels.

Back 17

True.

Front 18

T or F: Macula Densa are the specialized cells in the descending loop of Henle which detect increases in [NaCl] of tubular fluid

Back 18

False. Macula Densa are the specialized cells in the ASCENDING loop of Henle which detect increases in [NaCl] of the tubular fluid.

Front 19

What do macula densa do in repsonse to high levels of NaCl in the tubular fluid?

Back 19

Release ATP, which triggers contraction of afferent arterioles...thereby reducing GFR.

Front 20

How is GFR regulated 'externally'?

Back 20

Renal sympathetic nerves release noradrenaline, which triggers constriction of afferent arterioles. A decreased urine production prevents reduction in blood vol. and BP.

Front 21

T or F: 99% of filtrate is reabsorbed in the nephron and is returned to the vasculature.

Back 21

True

Front 22

T or F: Reabsorption of the filtrate is carried out by epithelial cells lining the inner wall of the nephron.

Back 22

True.

Front 23

Reabsorption of ___ is the driving force for reabsorption of other filtrate constituents.

Back 23

Na+

Front 24

How is Na+ reabsorbed in the proximal tubule? (What type of transport?)

Back 24

Active transport;

Front 25

The energy released during movement of Na+ down a gradient also drives reabsorption of other molecules like glucose and amino acids. What type of transport is this?

Back 25

Co-transport.

Front 26

What molecules follow the movement of Na+, glucose, and amino acids? (Using passive transport)

Back 26

Cl- and H2O

Front 27

What does glomerular filtrate consist of?

Back 27

Plasma minus plasma proteins

Front 28

T or F: Glomerular filtrate is isosmotic with plasma.

Back 28

True. Both = 300 mOsm.

Front 29

Because salt and water transport are ______, filtrate exiting the PT is still isosomtic with plasma and is 300 mOsm.

Back 29

coupled

Front 30

T or F: The loop of Henle determines the osmolarity of tubular fluid using countercurrent multiplier system (CMS).

Back 30

False. The loop of Henle determines the osmolarity of URINE using the CMS.

Front 31

Briefly describe the countercurrent multiplier system.

Back 31

Dehydration- low vol, [ ]ed urine is produced

Excess hydration- high volume, dilute urine is produced

Front 32

Where is the site of urine concentration determination?

Back 32

The collecting duct.

Front 33

T or F: The CMS achieves the need to keep the osmolarity of interstitial fluid high and the osmolarity of tubular fluid to be low.

Back 33

True.

Front 34

T or F: The absorption of NaCl and H20 is coupled.

Back 34

False. Only the transport of these two molecules is coupled. Because there are no aquarporins in the ascending limb of the loop of Henle, there is NO H20 TRANSPORT.

Front 35

T or F: After reabsorption, the tubular filtrate is "salty" and the medulla is diltue.

Back 35

False. After Na+ reasborption, the tubular fluid becomes dilute and the MEDULLA becomes "salty".

Front 36

T or F: Vasa Recta are long blood vessels that parallel the loop of Henle

Back 36

True

Front 37

T or F: Fluid leaving the collecting duct is urine.

Back 37

True/

Front 38

As the abundance of AQP2 increases, the rate of water absorption decreases.

Back 38

False as AWP2 increases, H20 absorption also increases.

Front 39

T or F: As urine volume increases,it's osmolarity decreases.

Back 39

True.

Front 40

T or F: ADH triggers the insertion of AQ2 into the apical membrane to increase reabsorption.

Back 40

True.

Front 41

T or F: Aldosterone stimulates an increase in Na+ reabsorption.

Back 41

True.

Front 42

T or F: Alkalosis is a decrease in pH.

Back 42

False. Acidosis is a drop in pH. Alkalosis is an increase in pH.

Front 43

T or F: Glycosuria is a sign of diabetes mellitus.

Back 43

True. Glucose should not normally exist in the urine.