Download Osmoregulation and Routine Urinalysis

Peachy Mae A. Pineda
Urinary System

The urinary system (also called
excretory system) is the organ system
that produces, stores, and eliminates
urine.
 It consist of the kidneys, ureters, urinary
bladder, and urethra.
Urinary System
Renal artery
Kidneys
Renal vein
re
Aorta
Ureters
Inferior vena cava
Urinary bladder
Urethra
Kidney

is a compact, bean-shaped organ attached
to the dorsal body wall outside the
peritoneum.

its main roles are to regulate volume and
composition of the body fluids.

the structure of the kidney consists of the
cortex, medulla (inner and outer zones of
outer medulla and papilla or inner medulla),
pyramids, renal calyxes and pelvis, and
ureters.
Kidneys
MEDULLA
CORTEX
RENAL
PYRAMID
RENAL
PELVIS
URETER
MAJOR
MINOR
CALYXES
General Functions of the Kidney
Blood Filtering
 Excretion of Waste
 Homeostasis

 Acid-base balance
 Blood pressure
 Plasma volume

Hormone Secretion
General Functions of the Kidney
*Blood Filtering

Takes place in the nephron.

Blood pathway in the kidney (entering)
 renal artery in the renal sinus
 branches into segmental arteries
 further divide into interlobar arteries
 then supply blood to the arcuate arteries
 supply a variety of additional interlobar arteries
 afferent arterioles to be filtered through.
General Functions of the Kidney
*Blood Filtering

Blood pathway in the kidney (exiting)
 blood moves through a small network of venules
that converge into interlobar veins
 the interlobar provide blood to the arcuate veins
 back to the interlobar veins
 form the renal vein exiting the kidney for
transfusion for blood
General Functions of the Kidney
*Excretion of Waste Products

The excreted product came from the
waste produced by metabolism.

Mostly nitrogenous waste: UREA and
URIC ACID, and Water.

It is excreted through urine.
General Functions of the Kidney
*Homeostasis

The kidney is one of the major organs
involved in whole-body homeostasis.

Among its homeostatic functions are
acid-base balance, regulation of
electrolyte concentrations, control of
blood volume, and regulation of blood
pressure.
General Functions of the Kidney
*Homeostasis

Acid-base balance
 The kidneys regulate the pH of blood by
adjusting H+ ion levels, referred as
augmentation of mineral ion concentration,
as well as water composition of the blood.

Blood pressure
 Sodium ions are controlled in a homeostatic
process involving aldosterone which
increases sodium ion reabsorption in the
distal convoluted tubules.
General Functions of the Kidney
*Homeostasis

Plasma volume
 Controlled by hypothalamus.
 (together with posterior pituitary gland)
hypothalamus secretes antidiuretic hormone.
 resulting in water reabsorption by the kidney and
an increase in urine concentration.
 The two factors work together to return the
plasma osmolarity to its normal levels
General Functions of the Kidney
*Hormone Secretions

The kidneys secrete a variety of hormones.
 Erythropoietin is released in response to low
levels of O2 in the renal circulation. It stimulates
erythrocyte production in red bone marrow.
 Renin is involved in the regulation of
aldosterone secretion.
 Calcitriol, the activated form of vitamin D,
promotes the absorption of Ca2+ from the blood
and the excretion of PO32-. They both help to
increase Ca2+ levels.
Kidneys
*Nephrons

Nephrons are microscopic tube-like
structures in the kidneys which mainly
facilitates the functions of the kidney.

They are the most basic structural and
functional unit of the kidney, and are an
integral part of the urinary system.

Each kidney contains approximately one
million of them.
Kidney
*Nephrons
Glomerulus
 Proximal
convoluted
tubule


Loop of Henle
Distal
Convoluted
tubule
 Collecting
ducts

Kidney
*Glomerulus

A capillary network
enclosed by the a cupshaped tructure called
the Bowman's capsule.

Together with the
Bowman’s capsule,
glomerulus is called the
Renal corpuscle.

The renal corpuscle (or
Malpighian corpuscle) is
the beginning of the
nephron.
Kidney
*Glomerulus

It is the nephron's initial filtering component.

It regulates the concentration of essential
substances, and removes substances not
produced by the body.

Blood enters the glomerulus, it is filtered out to
the space made by the Bowman’s capsule.

The blood then enters the convoluted tubules
through the interstitial space, combines with
efferent venules of other glomerulus then rejoins
the main blood stream.
Kidney
*Renal Tubule

Renal tubule or the
convoluted tubules
is composed of
proximal convoluted
tubule, (2) loop of
Henle, and (3) distal
convoluted tubule.
Renal tubule
*Proximal Convoluted tubule

Can be divided into an initial
convoluted portion and a
following straight
(descending) portion.

Fluid entering the proximal
convoluted tubule is
reabsorbed into the
peritubular capillaries,
including filtered salt and
water and all filtered organic
solutes.
Renal Tubule
*Loop of Henle

Also called the nephron
loop, is a U-shaped
tube that extends from
the proximal tubule.

The primary role of the
loop of Henle is to
concentrate the salt in
the interstitium, the
tissue surrounding the
loop.

It consists of a
descending limb and
ascending limb.
Renal Tubule
*Loop of Henle

It begins in the cortex, receiving filtrate from the
proximal tubule, extends into the medulla as the
descending limb, and then returns to the cortex as the
ascending limb (hairpin turn)to empty into the distal
convoluted tubule.

The descending limb is permeable to water but
completely impermeable to salt, and thus making the
interstitium hypertonic.

The ascending limb is impermeable to water, a critical
feature of the countercurrent mechanism. It actively
pumps sodium out of the filtrate, because of this the
fluid became more hypotonic.
Renal Tubule
*Distal Convoluted Tubule

Cells lining the tubule
have numerous
mitochondria to
produce enough
energy (ATP) for
active transport to
take place.

Regulated by the
endocrine system.
Renal Tubule
*Distal Convoluted Tubule

In the presence of parathyroid hormone, the
distal convoluted tubule reabsorbs more
calcium and excretes more phosphate.

Aldosterone promotes more sodium to be
reabsorbed and more potassium to be
excreted.
Atrial natriuretic peptide causes the distal
convoluted tubule to excrete more sodium.


In addition, the tubule also secretes hydrogen
and ammonium to regulate pH.
Collecting Ducts

The distal
convoluted tubules
of several nephrons
empty into a single
collecting duct.

Collecting ducts
then unite and
converge to form
papillary ducts.
Collecting Ducts

As the filtrate moves through the renal tubule, the
osmolarity of the filtrate changes.

As it moves deeper into the medulla, it increases, and
when it ascends the loop of Henle, it decreases only to
increase again while going down the collecting duct.

It is this hyperosmotic condition in the medulla that
allows passive transport to occur.

Collecting duct is normally impermeable to water, it
becomes permeable in the presence of antidiuretic
hormone (ADH). Lower portions of the collecting duct
are also permeable to urea..
Urine Formation
*What is Urine?

The waste product secreted by the kidneys that in
mammals is a yellow to amber-colored, slightly acid
fluid discharged from the body through the urethra.

An aqueous solution of organic and inorganic
substances, mostly waste products of metabolism.

It consists of water, carrying in solution the body's
waste products such as urea, uric acid, creatinine,
organic acids, and also other solutes such as Na+, K+,
Ca2+, Mg2+, Cl-, the body fluid concentrations of which
are regulated by the kidneys.
Urine formation

The production of urine is vital to the health
of the body.

“Cleaning" of the blood takes place in the
kidneys and, in particular, in the nephrons,
where the blood is filtered to produce the
urine.

The kidneys' 2 million or more nephrons
form urine by three precisely regulated
processes.
Urine Formation

The three processes are the following:
A. Glomerulus Filtration
B. Tubular Reabsorption
C. Tubular Secretion
Expressed mathematically as:
Urinary excretion rate = Filtration rate – Reabsorption rate +
Secretion rate
Urine Formation
*1.Glomerular Filtration

Urine formation begins with the process of filtration,
which goes on continually in the renal corpuscles
(glomerulus and Bowman’s capsule).

As blood courses through the glomeruli, much of its
fluid soaks out of the blood through the membranes
(by osmosis and diffusion) where it is filtered and
then flows into the Bowman's capsule.

The water, waste products, salt, glucose, and other
chemicals that have been filtered out of the blood are
known collectively as glomerular filtrate
Urine Formation
*1.Glomerular Filtration

The glomerular filtrate consists primarily of
water, excess salts (primarily Na+ and K+),
glucose, and a waste product of the body
called urea.

The total rate of glomerular filtration
(glomerular filtration rate or GFR) for the
whole body is normally about 125 ml per
minute. That is, about 125 ml of water and
dissolved substances are filtered out of the
blood per minute.
Urine Formation
*Glomerular Filtration

The GFR per hour is:
 125 ml/min X 60min/hr= 7500 ml/hr.

The GFR per day is:
 7500 ml/hr X 24 hr/day = 180,000 ml/day or
180 litres/day.
Urine Formation
*2.Tubular Reabsorption

Reabsorption is the movement of substances out of
the renal tubules and collecting ducts back into the
blood capillaries located around the tubules (called the
peritubular copillaries).

Substances reabsorbed are water, glucose and other
nutrients, and sodium (Na+) and other ions.

Reabsorption begins in the proximal convoluted
tubules and continues in the loop of Henle, distal
convoluted tubules, and collecting tubules.
Urine formation
*2.Tubular Reabsorption

Large amounts of water about 99% of the
180 liters of water that leave the blood
each day by glomerular filtration returns to
the blood from the proximal tubule through
the process of passive reabsorption.

The nutrient glucose (blood sugar) is
entirely reabsorbed back into the blood
from the proximal tubules. In fact, it is
actively transported out of the tubules
and into the peritubular capillary blood.
Urine Formation
*2.Tubular Reabsorption

Sodium ions (Na+) and other ions are only
partially reabsorbed from the renal tubules
back into the blood.

Sodium ions are actively transported
back into blood from the tubular fluid.

The amount of sodium reabsorbed varies
from time to time; it depends largely on
how much salt we take in from the foods
that we eat.
Urine Formation
*3.Tubular Secretion

Secretion is the process by which substances
move into the distal and collecting tubules
from blood in the capillaries around these
tubules.

Secretion is reabsorption in reverse.

Whereas reabsorption moves substances out
of the tubules and into the blood, secretion
moves substances out of the blood and into
the tubules where they mix with the water and
other wastes and are converted into urine.
Urine Formation
*3.Tubular Secretion

These substances are secreted through either
an active transport mechanism or as a result
of diffusion across the membrane.

Substances secreted are hydrogen ions (H+),
potassium ions (K+), ammonia (NH3), and
certain drugs.

Kidney tubule secretion plays a crucial role in
maintaining the body's acid-base balance
Summary of Urine Formation
Characteristics of Normal Urine
Characteristic
Description
Amount
1–2 liters per 24 hours; highly variable
depending on fluid intake and water loss through
the skin.
Color
Straw or amber; darker means more
concentrated; should be clear, not cloudy.
Specific Gravity
1.010–1.025; a measure of the dissolved
material in urine; the lower the value, the more
dilute the urine.
pH
Average 6; range 4.6–8.0; diet has the greatest
effect on urine pH
Composition
95% water; 5% salts and waste products
Nitrogenous Wastes
Urea—from amino acid metabolism
Creatinine—from muscle metabolism
Uric acid—from nucleic acid metabolism
Abnormal Constituents in Urine
Characteristics
Reasons
Glycosuria (presence of glucose)
In an untreated diabetic, for example, blood glucose is too high;
therefore the filtrate glucose level is too high. The kidneys
reabsorb glucose up to their threshold level, but the excess
remains in the filtrate and is excreted in urine.
Proteinuria (presence of protein)
Most plasma proteins are too large to be forced out of the
glomeruli, and the small proteins that enter the filtrate are
reabsorbed by pinocytosis. The presence of protein in the urine
indicates that the glomeruli have become too permeable, as
occurs in some types of kidney disease.
Hematuria (presence of bloodRBCs)
Another possible cause might be bleeding somewhere in the
urinary tract. Pinpointing the site of bleeding would require
specific diagnostic tests.
Bacteriuria (presence of bacteria)
Bacteria give urine a cloudy rather than clear appearance;
WBCs may be present also. The presence
of bacteria means that there is an infection somewhere in the
urinary tract. Further diagnostic tests would be needed to
determine the precise location.
Ketonuria (presence of ketones)
Higher levels of ketones indicate an increased use of fats and
proteins for energy. This may be the result of malfunctioning
carbohydrate metabolism (as in diabetes mellitus)
or simply the result of a high-protein diet.
Osmoregulation

Regulation of the concentration of
dissolved substances in the cells and
body fluids (e.g. blood) of an animal.

Importance: Maintains homeostasis
○
cells being bathed in tissue fluid which
has the correct amount of water, mineral
salts, glucose and temperature.
Osmoregulation
the physiological processes that an
organism uses to maintain water balance;
that is, to compensate for water loss, avoid
excess water gain, and maintain the proper
osmotic concentration (osmolarity) of the
body fluids
 Most humans are about 55 to 60 percent
water by weight (45 percent in elderly and
obese people and up to 75 percent in
newborn infants).

Procedure
Four subjects were
asked to drink 500 ml
of coffee, water, brine
solution and soft
drinks
Amount of urine
excreted was noted.
Urine samples were
collected thrice with
an interval of 30
minutes.
Physical
characteristics of
urine were noted.
Results and Discussions
Volume of Urine Produced
Subject
First
collection
Second
collection
Third
collection
Total
Subject 1
(water)
150 mL
240 mL
200 mL
590 mL
Subject 2
(brine
solution)
275 mL
225 mL
75 mL
575 mL
Subject 3
(soft drink)
150 mL
70 mL
200 mL
420 mL
Subject 4
(coffee)
40 mL
180 mL
110 mL
330 mL
Results and Discussions
Chart Title
800
700
Axis Title
600
500
subject 4
subject 3
subject 2
subject 1
400
300
200
100
0
1st col
2nd col.
3rd col
Results and Discussions
Total Volume of Urine Produced
700
600
590
Total volume
575
500
420
400
330
300
200
100
0
Subject 1
Subject 2
Subject 3
Subject 4
•1(water)
•2(brine soln.)
•3(soft drink)
•4(coffee)
Results and Discussions

Diuretics
 Increase urine output by the kidney
 Promote diuresis
Results and Discussions

Caffeine is a natural diuretic.
 It makes you secrete more urine.
 It is found in coffee, tea, soft drinks, and
chocolate.
Results and Discussions
 If
caffeine promotes diuresis, then
why does coffee and soft drinks which
contain caffeine only ranked fourth
and third respectively in volume of
urine excreted?
Results and Discussions

Subsequent studies have further shown
that the mechanism of caffeine diuresis
is dubious in nature, as caffeine
containing beverages did not impact
urinary output any differently, when
compared to other beverages that do
not contain caffeine. However, this does
not mean that caffeine does not
increase your need or urge to urinate.
Results and Discussions

The antidiuretic hormone (ADH) or
vasopressin stimulates the kidney
tubules to absorb water from the filtered
plasma that passes through the kidneys
and thus regulates the amount of urine
secreted by the kidneys

Sodium chloride is antidiuretic in a
sense that it stimulates ADH production
Results and Discussions

When the amount of salt and other
substances in the bloodstream becomes
too high, the pituitary gland releases
ADH into the bloodstream. When it
enters the kidney, ADH makes the walls
of the renal tubules and collecting ducts
more permeable to water, so that more
water is reabsorbed into the
bloodstream  decreased urine
output
Conclusion
Osmoregulation: control of the concentration of
dissolved substances in the cells and body
fluids (e.g. blood) of an animal and is important
because it helps maintain homeostasis.
 Kidneys are delicate organs needed in the
excretion of wastes.
 Two types of substances that can affect
osmoregulation: diuretics and antidiuretics
 Diuretics, increases urine output
 Antidiuretics decreases urine output

Practical Application
◦ Medicines:
◦ antidiuretics and diuretics (furosemide)
◦ Diuretics are administered to patients with diseases
relating to high water retention and those with congenital
heart diseases.
◦ Antidiuretics (synthetic vasopressin) is given to patients
with Diabetes insipidus (deficiency of vasopressin)
 Patients often experience increased thirst and urination.
Treatment is with drugs, such as synthetic vasopressin,
that help the body maintain water and electrolyte
balance.
Practical Applications

Clinical tests: Measurements of the
composition of urine are useful in the
diagnosis of a wide variety of conditions,
including kidney disease, diabetes, and
pregnancy.
Routine Urinalysis

Urinalysis, or examination of the urine, indicates
whether any abnormal substances are present in
the urine.

This is done to screen for possible presence of
diseases that could be detected in the urine
sample.

A complete urinalysis has three stages:
1.Physical Examination
2. Chemical Examination
3. Microscopic Examination
Procedure

I. Physical Examination of Urine
Fresh urine samples
were placed in a
beaker.
Volume, color,
transparency, odor of
urine were noted.
Using the ___, ph,
specific gravity,
presence of glucose
and protein were
noted.
Results

Physical Examination of Urine Samples
Subject 1
Subject 2
Subject 3
Subject 4
Color
Pale yellow
Straw yellow
Yellow orange Orange
pH
Acidic (5.5)
Acidic(6)
Acidic(6)
Acidic(5.5)
Transparency
Clear
Clear
Cloudy
Clear
Glucose
0
0
0
0
Protein
+/-0.15
+ 0.15
+1(0.3)
0
Specific Gravity
1.025
1.015
1.020
1.025
Refractory
1.02
1.00
1.021
1.033
Procedure

Chemical Examination of Urine
 Benedict’s test
5 mL of Benedict’s
reagent was mixed
with 8 drops of
uncentrifuged urine.
Mixed solution was
heated for 5 minutes.
If positive: a
precipitate will form
with colors ranging
from green, yellow,
orange to red.
Results

None of the urine
samples is positive
to Benedicts test, it
simply implies that
glucose is not
present in the urine.
Procedure
Chemical Examination of Urine
•Heat and Acetic Acid Test
The fresh urine
sample was
centrifuged for 5
mins, then the
sediments were
decanted
The upper half of the
urine was heated
using an alcohol
lamp. The bottom
part was not heated
for comparison
The presence of
turbidity or cloudiness
was observed
Few drops of 10 %
Acetic acid was
added
Results and Discussions
Results

Normally, only small plasma proteins filtered at the
glomerulus are reabsorbed by the renal tubule. The
detection of protein in urine may indicate that the
permeability of the glomerulus is abnormally increased.

May be caused by renal infections or it may be caused by
other diseases that have secondarily affected the kidneys
such as diabetes mellitus, jaundice, or hyperthyroidism.

Normal total protein excretion does not usually exceed
150 mg/24 hours or 10 mg/100 ml in any single specimen.
More than 150 mg/day is defined as proteinuria.

Proteinuria > 3.5 gm/24 hours is severe and known as
nephrotic syndrome.
Microscopic Examination
The sediment from
the previous test
was utilized.
It was then placed
in a glass slide
It was viewed under
LPO and HPO.
In LPO, mucus
threads, epithelial
cells, crystals
(
urates, oxalates) were
observed
In HPO, bacteria,
RBCs and WBCs
were observed
Microscopic Examination
Casts

Urinary casts are formed only in the distal convoluted tubule
(DCT) or the collecting duct (distal nephron).

Their presence indicates inflammation of the kidney,
because such casts will not form except in the kidney.
Conditions which may lead to:
1. lupus nephritis
2. malignant hypertension
3. diabetic glomerulosclerosis
4. rapidly progressive glomerulonephritis
Microscopic Examination

RBC (Red Blood Cells) Casts

RBC in urine - indicative of glomerulonephritis, with
leakage of RBC's from glomeruli, or severe tubular damage.

Hematuria - the presence of red blood cells (erythrocytes) in
the urine.
Microscopic Examination

White blood cell casts
Sterile pyuria is urine which contains white blood cells while appearing
sterile by standard culturing techniques. Sterile pyuria is listed as a side
effect from some medications such as paracetamol (acetaminophen).
Its occurrence is also associated with certain disease processes, such
as Kawasaki Disease and renal TB
Microscopic Examination
Renal Tubular Epithelial Cells
 usually larger than granulocytes, contain a large round or oval
nucleus and normally slough into the urine in small numbers.
 smaller and rounder than transitional epithelium
Transitional Epithelial Cells
 from the renal pelvis, ureter, or bladder have more regular cell
borders, larger nuclei, and smaller overall size than squamous
epithelium.
Squamous Epithelial Cells
 from the skin surface or from the outer urethra can appear in urine.
Their significance is that they represent possible contamination of
the specimen with skin flora.
Microscopic Examination
Yeast
 Yeast cells may be contaminants or represent a
true yeast infection. They are often difficult to
distinguish from red cells and amorphous crystals
but are distinguished by their tendency to bud.
Most often they are Candida, which may colonize
bladder, urethra, or vagina.
Microscopic Examination
Crystals
Common crystals seen even in healthy
patients include calcium oxalate, triple
phosphate crystals and amorphous
phosphates.
 Very uncommon crystals include: cystine
crystals in urine of neonates with congenital
cystinuria or severe liver disease, tyrosine
crystals with congenital tyrosinosis or marked
liver impairment, or leucine crystals in
patients with severe liver disease or with
maple syrup urine disease.

Microscopic Examination

Amorphous crystals
 appear as aggregates of
finely granular material
without any defining
shape
 Amorphous urates of
Na, K, Mg or Ca tend to
form in acidic urine
 Amorphous phosphates
tend to form in alkaline
urine
Microscopic Examination
Bacteria
Bacteria are common in urine
specimens because of the abundant
normal microbial flora of the vagina or
external urethral meatus and because
of their ability to rapidly multiply in
urine standing at room temperature.
 Therefore, microbial organisms found
in all but the most scrupulously
collected urines should be interpreted
in view of clinical symptoms.

Results and Discussions

Subject 1(water)
Under LPO
Abundance
Amorphous urates
Some
Epithelial Cells
Occasional
Mucus Threads
Rare
Renal Cells
Rare
Casts
None
Other crystals
Rare
Under HPO
Abundance
Red Blood Cells
1
White Blood Cells
1
Bacteria
10
Results and DDcussions

Subject 2(brine)
Under LPO
Abundance
Amorphous urates
rare
Epithelial Cells
Few
Mucus Threads
Occasional
Renal Cells
None
Casts
None
Other crystals
Rare
Under HPO
Abundance
Red Blood Cells
0
White Blood Cells
1
Bacteria
15
Results and Discussions

Subject 3(Softdrink)
Under LPO
Abundance
Amorphous urates
Rare
Epithelial Cells
Few
Mucus Threads
Occasional
Renal Cells
none
Casts
None
Other crystals
Rare
Under HPO
Abundance
Red Blood Cells
0
White Blood Cells
0
Bacteria
20
Results and Discussions

Subject 4( Coffee)
Under LPO
Abundance
Amorphous urates
Some
Epithelial Cells
Rare
Mucus Threads
Some
Renal Cells
Rare
Casts
None
Other crystals
Few
Under HPO
Abundance
Red Blood Cells
1
White Blood Cells
1
Bacteria
24
Results and Discussions
White bloods cells
Results and Discussions
Red bloods cells
Results and Discussions
Mucus Threads
Results and Discussions
Bacteria
Conclusion

The presence of glucose in the urine
usually indicates that the individual has
diabetes mellitus, a condition in which
either the liver fails to store glucose as
glycogen or the cells fail to take up
glucose. In both cases, the blood glucose
level is abnormally high.

This makes the filtrate level of glucose
high, and because the proximal convoluted
tubule cannot absorb all of it, glucose
appears in the urine.
Practical Applications

Diabetes insipidus
 Diabetes insipidus (DI) is a rare disease that
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causes frequent urination and excessive
thirst.
DI is not related to diabetes mellitus (DM).
excessive intake of fluid
a defect in ADH production
a defect in the kidneys’ response to ADH
Practical Applications
Central DI results from damage to the
pituitary gland which disrupts the normal
storage and release of ADH
 Nephrogenic DI results when the
kidneys are unable to respond to ADH
 Dipsogenic DI, which is caused by a
defect in the thirst mechanism.
 Gestational DI results when an enzyme
made by the placenta destroys ADH
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Practical Applications
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Polyuria
 The excessive passage of urine (at least 2.5
liters per day for an adult) resulting in
profuse urination and urinary frequency (the
need to urinate frequently).
 Caused by DI, increase uptake of water, or
uptake of diuretics
Practical Applications
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Anuria and oliguria
 The absent or decreased urine production,
respectively
 failure in the function of kidneys
 severe obstruction like kidney stones or
tumours