Chapter 7: Nephrology: Topic 1- Renal Anatomy and Physiology

Question 1

Name the 3 stages of embryonic kidney development and indicate which stage will form the definitive human kidney

Answer 1

1. Pronephros- disappears
2. Mesonephros –> BC, glomerulus, mesonephric duct
3. Metanephros –> kidneys

Question 2

When the mesonephric kidney degenerates, what does the cranial end of the mesonephric duct form in males?

Answer 2

under the influence of testosterone, it forms the ductus deferens, ejaculatory duct and seminal gland

Question 3

What structure begins the formation of the definitive human kidney?

Answer 3

The ureteric bud, –> collecting system

Question 4

Where does the definitive human kidney initially develop?

Answer 4

in the pelvis

Question 5

The embryonic origin of the bladder and urethra is

Answer 5

urogenital sinus

Question 6

Name 3 malformations evident in a stillborn infant that succumbed from bilateral frenal agenesis (Potter sequence)

Answer 6

oligohydramnios –> craniofacial anomalies, pulmonary hypoplasia, clubbed feet

Question 7

What vessel blocks the ascent of a horseshow kidney?

Answer 7

inferior mesenteric artery

Question 8

In a newborn with a patent urachus, there will be abnormal drainage of urine from

Answer 8

the umbilicus, via a fistula

Question 9

the 3 main anatomic regions of the kidney are

Answer 9

cortex, medulla, hilum

Question 10

Which nephrons have short loops of Henle and which nephrons have long ones?

Answer 10

Outer cortex, short ones: cortical nephrons

Inner cortex, long ones: juxtamedullary nephrons

Question 11

Name the 3 structures, in order, through which urine will pass to reach the ureter, beginning at the apex of a renal pyramid.

Answer 11

minor calyx
major calyx
renal pelvis

Question 12

If potter sequence develops from renal agenesis, what features are seen?

Answer 12

oligohydramnios–> club feet, pulmonary hypoplasia, craniofacial: flat noes, recessed chin

Question 13

Failure of the allantois to obliterate embryologically can cause what problem?

Answer 13

Patent urachus–> leak urine via umbilicus

Question 14

Name and briefly describe the 4 basic renal processes

Answer 14

filtration- water/ solute from G. capillary –> Bowman’s space
Reabsorption- solute/ water from lumen –> peritubular capillaries
secretion
excretion- water/ solute loss in the urine

Question 15

About __ of the body mass is water and its distribution is ___ extracellular and ___ intracellular

Answer 15

60%
1/3
2/3

Question 16

Four grams of inulin is infused into a patient and the plasma concentration of inulin is 250 mg/ ml after steady state ahas been achieved. What compartment is measured, and what is the volume of this compartment?

Answer 16

Extracellular volume

V = A/C amount/ concentration. 4g/.25 = 16 L

Question 17

Does the tracer measure plasma, extracellular, or total body compartments?
I-albumin, Evan’s blue dye, Cr red blood cell

Answer 17

Plasma

Question 18

Does the tracer measure plasma, extracellular, or total body compartments? Inulin, mannitol, 22Na+, sucrose

Answer 18

Extracellular

Question 19

Does the tracer measure plasma, extracellular, or total body compartments? Heavy water, tritiated water, urea, antipyrine

Answer 19

Total

Question 20

Under normal circumstances, ____ and ____ compounds are not filtered at the glomerular capillary

Answer 20

plasma proteins

lipid soluble

Question 21

Define GFR and indicate the force producing it

Answer 21

rate fluid is filtered into Bowman’s space

Pressure in glomerular capillary (Pgc)

Question 22

The equation for filtration fraction. What variable influences it directly?

Answer 22

FF = GFR/ RPF

Oncotic pressure in peritubular capillaries directly related to FF

Question 23

What impact do sympathetics have on RPF, GFR and FF?

Answer 23

(affect both, but afferent more than efferent)

RPF very much down, GFR down, FF up

Question 24

What impact does Angiotensin II have on RPF, GFR and FF?

Answer 24

(affect efferent more than afferent)

RPF down, GFR up, FF up

Question 25

What is the important role of prostaglandins in the regulation of renal blood flow? Which over-the-counter compounds block prostaglandin production?

Answer 25

Maintain dilation of afferent arteriole

NSAIDS

Question 26

Equation for clearance. The clearance of which compound is a measure of GFR? Why?

Answer 26

C= UV/P Urine concentration, flow, plasma concentration

Inulin; it is freely filtered and not secreted or reabsorbed

Question 27

Plasma creatinine is used as a marker of renal function because it

Answer 27

is freely filtered, not reabsorbed. Inverse relationship between plasma creatinine and GFR

Question 28

The clearance of ___ is a measure of effective renal plasma flow, and it is utilized for this measurement because if the plasma concentration is low enough, all of it is ____

Answer 28

PAH

secreted

Question 29

Compound X is infused into a patient until it reaches a steady-state plasma concentration of 100 mg/dl. Once steady state is reached, the urine concentration of X is 2 mg/ml and urine flow is 1 ml/ min. Inulin clearance is 100 ml/min. Given this, is there net secretion or reabsorption of X? what is the rate of this reabsorption or secretion, and is the clearance of X greater than, equal to or less than GFR?

Answer 29

Filtered load = GFR * Px = 100 mg/min (rate solute enters nephron)

Rate of excretion = UV = 2 mg/ml * 1 ml/min

Filtered load is greater than excretion; therefore reabsorbed at filtered load - excretion = 98 mg/min