CHAPTER 32 (PORTH 2020) KIDNEY AND URINARY

Question 1

A 32-year-old woman with diabetes is found to have a positive result on a urine dipstick test for microalbuminuria. A subsequent 24-hour urine specimen reveals an albumin excretion of 50 mg (an albumin excretion >30 mg/day is abnormal).

A.Use the structures of the glomerulus in Figure 32-5 to provide a possible explanation for this finding. Why specifically test for the albumin rather than the globulins or other plasma proteins?

Answer 1

A.Urine formation involves
1. the filtration of blood through the glomerulus to form an ultrafiltrate of urine
2. the tubular reabsorption of electrolytes and nutrients is needed to maintain the internal environment’s constancy while eliminating waste materials.

The movement of fluid through the glomerular capillaries is determined by the same factors that facilitate fluid movement in all capillary beds: capillary hydrostatic pressure (filtration pressure), capillary colloidal osmotic pressure (reabsorptive pressure), and capillary permeability

albumin: Is too large to pass through the pores in the capillary wall; therefore, it remains in the circulation, where it contributes to the plasma osmotic pressure and maintenance of blood volume

Question 2

Each _______has a _______that filters the blood and a system of tubular structures that selectively reabsorb needed substances back into the blood and secrete unneeded substances into the tubular _______that will become urine.

Answer 2

nephron
glomerulus
filtrate

Question 3

Under conditions of decreased perfusion or increased sympathetic nervous system stimulation, blood flow can be redistributed away from the cortex toward the __________.

Answer 3

medulla

Question 4

Under conditions of decreased perfusion or increased sympathetic nervous system stimulation, blood flow can be redistributed away from the cortex toward the
________

Answer 4

medulla

Question 5

The kidney is sheathed in a_______ external capsule and surrounded by a mass of ______ _________tissue, particularly at the ends and borders.

Answer 5

fibrous
fatty
connective

Question 6

A single renal _______arises on either side of _______the to supply each ______.

Answer 6

artery
aorta
kidney

Question 7

What is the term for this definition?
Away from or being the farthest from the point of reference.

Answer 7

distal

Question 8

Alterations in the structure and function of the glomerular basement membrane are responsible for the leakage of proteins and blood cells into the
_________ glomerus.

Answer 8

filterate

indication: glomerulus disease

Question 9

Mesangial cells exhibit contractile properties in response to neurohumoral substances and are thought to contribute to the regulation of blood flow through the
______

Answer 9

glomerulus

Question 10

The size of the ______
basal in the basement membrane normally prevents red blood cells and plasma proteins from passing through the glomerulus into the filtrate.

Answer 10

pores

Question 11

In most cases, substances move across the luminal membrane along a concentration gradient but require facilitated transport or active carrier systems to move across the
________membrane into the
_______fluid, where the substances are absorbed into the _______

Answer 11

basolateral
interstitial
peritubular

Question 12

_______of ADH to the
_______receptors causes water channels, known as aquaporin-2 channels, to move into the luminal side of the tubular cell membrane, producing a marked increase in water ______

Answer 12

binding
vasopressin
permeability

Question 13

The ______ level at which the
_________ appears in the
__________ is called the renal threshold.

Answer 13

plasma
substance
urine

Question 14

Write a definition for Countertransport.

Answer 14

The process by which a substance moves across a membrane in opposite directions.

Question 15

The
______responds to changes in the
________ of the extracellular fluid by producing either concentrated or dilute ________.

Answer 15

kidney
osmolarity
urine

Question 16

The osmolarity of body fluids relies heavily on the ability of the
______ to produce dilute or concentrated urine.

Answer 16

kidney

Question 17

When ADH is present, the water that moves from the blood into the urine filtrate in the _______ is returned to the circulatory system, and when ADH is absent, the water is excreted in the urine.

Answer 17

glomerulus

Question 18

Nitric oxide, a vasodilator produced by the vascular
_________ appears to be important in preventing excessive
_________ of renal blood vessels and allowing normal _________ of sodium and water.

Answer 18

endothelium
vasocontristion
excretion

Question 19

In the _______, _________ of blood flow must allow for precise _______ of solute and water excretion.

Answer 19

kidney
auto regulation
regulation

Question 20

Specialized
__________cells monitor the systemic
_________ blood pressure by sensing the stretch of the
_________arteriole and also monitor the concentration of sodium chloride in the tubular filtrate as it passes through the macula densa.

Answer 20

juxtaglomerular
arterial
afferent

Question 21

Write a definition for Juxtaglomerular.

Answer 21

• secretes, stores, enzyme renin
• an essential role in linking RBF to both GFR and the composition of the distal tubular fluid
• Monitor the systemic arterial blood pressure by sensing the stretch of the afferent arteriole.
  -Monitor the concentration of sodium chloride in the tubular filtrate as it passes through the macula densa.

Question 22

aldosterone
__________ acts on the distal________ to increase sodium__________ and exerts a longer-term effect on the maintenance of blood pressure.

Answer 22

aldosterone
tubule
reabsorption

Question 23

In addition to regulating body fluids and electrolytes, the kidneys function as an endocrine organ by producing
receptor_________ mediators that travel through the blood to distant sites where they exert their actions.

Answer 23

chemical

Question 24

ADH maintains _______ volume by returning water to the
__________ compartment, producing concentrated urine by removing water from the _______

Answer 24

extracellular
vascular
tubular

Question 25

People with end-stage renal disease are unable to transform vitamin D to its active form and may require pharmacologic preparations of the active vitamin (calcitriol) for maintaining mineralization of their
___________

Answer 25

bones

Question 26

With diminished renal function, there is a loss of renal concentrating ability, and the ______ The correct answer is urine. specific gravity may fall to levels of 1.006 to 1.010.

Answer 26

urine

Question 27

Because of the glomerular capillary
__________
________., less than 150 mg/L of protein is excreted in the
_________ over 24 hours in a healthy person.

Answer 27

filterate
barrier
urine

Question 28

The serum protein
___________ C has been demonstrated to serve as a useful marker of
glomerulus________ because it is also filtered at the ________but has a stable production rate across populations.

Answer 28

cystitis
GFR
Glomerulus

Question 29

Creatinine is a product of creatine
_________ in muscles that is freely filtered in the ________ and neither reabsorbed nor secreted in the tubules; therefore,
_________ creatinine levels are commonly used to estimate the GFR.

Answer 29

metabolism
glomeruli
serum

Question 30

Urine specific gravity is used to assess the _______ ability to concentrate urine.

Answer 30

kidneys

Question 31

Ureteroscopy involves the use of a smaller, thinner scope that may be used to remove stones from the ureter and aid in the treatment of ureteral disorders, such as ureteral
___________.

Answer 31

strictures

Question 32

___________ is used to visualize the structures of the kidneys and has proved useful in the diagnosis of many urinary tract disorders, including congenital anomalies, renal abscesses, hydronephrosis, and kidney stones.

Answer 32

ultrasonography