2. WHAT IS A GLOMERULUS?
The glomerulus (plural glomeruli) is a
network of small blood vessels (capillaries)
known as a tuft, located at the beginning
of a nephron in the kidney. Each of the two
kidneys contains about one million
nephrons.
3. WHAT SUBSTANCES ARE FILTERED
THROUGH THE CAPILLARIES?
The filtration membrane of the
kidney permeable enough to
allow water, urea, ions, and
glucose through.
4. WHAT SUBSTANCES DO NOT PASS
THROUGH THE FILTERS OF THE KIDNEY?
Proteins and red blood cells
cannot pass through the
filtration membrane and they
remain in the bloodstream.
5. HOW DOES THE KIDNEY MAINTAIN THE PROPER PH
BALANCE AND THE PROPER BALANCE OF WATER IN
THE BODY?
The kidneys help maintain the acid–base
balance by excreting hydrogen ions into the
urine and reabsorbing bicarbonate from the
urine.
6. WHAT DOES THE TERM
REABSORPTION REFER TO?
reabsorption or tubular reabsorption is the process by
which the nephron removes water and solutes from the
tubular fluid (pre-urine) and returns them to the circulating
blood
7. WHAT DOES THE TERM
SECRETION REFER TO?
Tubular secretion is the transfer of materials from
peritubular capillaries to the renal tubular lumen and
occurs mainly by active transport and passive diffusion.
8. WHAT ION, SECRETED IN THE TUBULES, IS
IMPORTANT IN MAINTAINING CONTROL OF THE
ACID/BASE BALANCE (PH) OF THE BLOOD?
The kidneys have two main ways to maintain acid-base
balance - their cells reabsorb bicarbonate HCO3− from
the urine back to the blood and they secrete hydrogen
H+ ions into the urine. By adjusting the amounts
reabsorbed and secreted, they balance the
bloodstream's pH.
9. IF THE PH OF THE BLOOD IS DROPPING, HOW
DO THE KIDNEYS MAINTAIN THE PROPER PH?
The kidneys respond to acid-base disturbances by modulating
both renal acid excretion and renal bicarbonate excretion. These
processes are coordinated to return the extracellular fluid pH, and
thus blood pH, to normal following a derangement.
10. WHAT DOES THE TERM
EXCRETION REFER TO?
is the process where all the metabolic wastes are
removed from the body.
Excretion in humans is carried through different body
parts and internal organs in a series of processes.
11. ACUTE TUBULAR NECROSIS
is the death of tubular cells, which may result
when tubular cells do not get enough oxygen
(ischemic ATN) or when they have been
exposed to a toxic drug or molecule
(nephrotoxic ATN).
12. WHAT ARE THE RISK FACTORS FOR ATN?
Certain medical and surgical situations are associated with a high risk
for developing ischemic ATN:
• Hypotension (low blood pressure)
• Obstetric (birth-related) complications
• Obstructive jaundice (yellow-tinged skin caused by blocked flow of
bile Prolonged prerenal state
• Sepsis (infection in the blood or tissues)
• Surgery (e.g., open heart surgery, repair of abdominal aortic
aneurysm)
13. SOME MEDICATIONS AND CLINICAL MATERIALS CAN
CAUSE NEPHROTOXIC ATN:
Aminoglycosides (antibacterial antibiotics such as streptomycin and
gentamicin)
Amphotericin B (antibiotic used to treat some forms of meningitis and
systemic fungal infections)
Cisplatin (anticancer agent used to treat late-stage ovarian and
testicular cancers)
Radio isotopic contrast media (agent used in certain imaging studies)
14. WHAT 2 BLOOD CHEMISTRY VALUES ARE REFLECTIVE
OF THE KIDNEYS ABILITY TO EXCRETE WASTE?
BUN (Blood urea nitrogen) test measures the amount of urea
nitrogen in your blood. Urea nitrogen is a waste product that
your kidneys remove from your blood.
CREATININE measures the level of creatinine in the blood. This
test is done to see how well your kidneys are working. Creatinine
can also be measured with a urine test. A measurement of the
serum creatinine level is often used to evaluate kidney function.
15. WHY ARE THESE VALUES ELEVATED IN THIS
PATIENT?
It is normally removed from your blood by your kidneys, but
when kidney function slows down, the BUN level rises. Patient
is unable to filter waste product.
As the kidneys become impaired for any reason, the creatinine
level in the blood will rise due to poor clearance of creatinine
by the kidneys.
16. WHAT BLOOD CHEMISTRY VALUES INDICATE
THE PATIENT IS IN METABOLIC ACIDOSIS?
Acidosis occurs when the blood pH falls
below 7.38 : Patients pH level is 7.33
17. WHAT ARE THE DANGERS OF
A HIGH K+ LEVEL?
Hyperkalemia occurs when potassium levels in your blood
get too high. Potassium is an essential nutrient found in
foods. This nutrient helps your nerves and muscles function.
But too much potassium in your blood can damage your
heart and cause a heart attack
18. WHY IS THE PATIENT EXPERIENCING EDEMA?
Due to retention of Sodium (Na+) .
Edema is primarily due to sodium
and water retention
19. DOES THE PRESENCE OF GLUCOSE AND PROTEIN
IN THIS URINE SAMPLE INDICATE THE PATIENT
MAY ALSO BE DIABETIC?
Normally, urine contains very little or no glucose. But if
you have too much glucose in your blood, your kidneys
will get rid of some of the extra glucose through your
urine. So, a high level of urine glucose may mean that
your blood glucose is high, too, and that could be a sign
of diabetes
20. WHAT ARE URINARY CASTS?
Urinary casts are tiny tube-shaped particles
that can be found when urine is examined
under the microscope during a test called
urinalysis . Urinary casts may be made up of
white blood cells, red blood cells, kidney
cells, or substances such as protein or fat.
21. WHAT FACTORS CONTRIBUTE TO
THE FORMATION OF CASTS IN
THE URINE?
The following factors promote the formation of casts in the
kidney:
• Larger than normal amounts of plasma proteins entering the
tubules
• Decreased pH
• Decreased urinary flow rate
• Increased urine concentration
22. WHAT RESULTS FROM THE URINALYSIS POINT
TO ACUTE RENAL FAILURE?
Presence of protein cells and
casts
23. WHICH HEALTH CARE PROFESSIONAL IS
RESPONSIBLE FOR TESTING THE BLOOD AND URINE
SAMPLE?
Medical laboratory science professionals (also called
clinical laboratory scientists or clinical laboratory
technicians) are highly skilled scientists who discover the
presence or absence of disease and provide data that help
physicians determine the best treatment for the patient.
24. WHAT ARE THE EFFECTS OF DIURESIS IN TREATING A
PATIENT WITH KIDNEY DISEASE?
diuretics are often prescribed to maintain or increase
urine output in patients presenting with acute kidney
injury (AKI). The rationale behind giving diuretics is
that they may protect the kidney from ischemic injury
by maintaining a nonoliguric state
25. WHY IS PROTEIN RESTRICTED IN THE DIET?
Having too much protein can cause waste
build up in your blood
Kidneys may not be able to remove all the
extra waste
26. WHAT IS RENAL DIALYSIS?
dialysis (from Greek dialusis meaning
dissolution, dia, meaning through, and lysis,
meaning loosening or splitting) is a process for
removing waste and excess water from the
blood, and is used primarily as an artificial
replacement for lost kidney function in people
with kidney failure
27. WHAT ARE THE 2 DIFFERENT
OPTIONS FOR A PATIENT
FACING RENAL DIALYSIS?
Hemodialysis
Peritoneal dialysis
28. HOW DO THESE 2 METHODS DIFFER?.
Hemodialysis: Blood is pumped from body to a filter where it is
purified and returned to the body
Peritoneal dialysis: Bodies peritoneal membrane is used as a filter.
Fluid is drained in and out of abdomen
29. LIST ADVANTAGES AND
DISADVANTAGES OF EACH
A.Hemodialysis
• Advantages: No patient training is required.
• Disadvantages: Dialysis graft failure, cannot be performed at home, lack
of freedom
B. Peritoneal dialysis
Advantages: It can be done at home--more freedom.
Disadvantages: Patient training, possible peritonitis and membrane
failure.
Editor's Notes
The function of glomerulus is to filter the blood passing through it and initiate urine formation.
The kidneys have two main ways to maintain acid-base balance - their cells reabsorb bicarbonate HCO3− from the urine back to the blood and they secrete hydrogen H+ ions into the urine. By adjusting the amounts reabsorbed and secreted, they balance the bloodstream's pH.
The substance that remains in the collecting duct of the kidneys following reabsorption is better known as urine.
Reabsorption includes passive diffusion, active transport, and cotransport.
Passive diffusion—passing through plasma membranes of the kidney epithelial cells by concentration gradients.
Active transport—membrane-bound ATPase pumps (such as NA+/K+ ATPase pumps) with carrier proteins that carry substances across the plasma membranes of the kidney epithelial cells by consuming ATP.
Cotransport—this process is particularly important for the reabsorption of water. Water can follow other molecules that are actively transported, particularly glucose and sodium ions in the nephron.
Secretion, which occurs in the proximal tubule section of the nephron, is responsible for the transport of certain molecules out of the blood and into the urine. Secreted substances include potassium ions, hydrogen ions, and some xenobiotics.
The tubular secretion of H+ (hydrogen) and NH4+ (ammonium) from the blood into the tubular fluid is involved in blood pH regulation. The movement of these ions also helps to conserve sodium bicarbonate (NaHCO3).
The typical pH of urine is about 6.0, while it is ideally 7.35 to 7.45 for blood.
pH regulation is primarily a respiratory system process, due to the exchange of carbon dioxide (a component of carbonic acid in blood), however tubular secretion assists in pH homeostasis as well.
derangement a disturbance of normal bodily functioning or operation
Fortunately, new tubular cells usually replace those that have died. Indeed, the tubular cells of the kidneys undergo a continuous cycle of cell death and renewal, much like the cells of the skin.
In the hospital setting, ATN is the most common cause of acute renal failure (ARF). Hospital patients often have acute medical problems that limit the oxygen supplied to the tubules or that cause tubular hypoperfusion (decreased blood flow).
BUN 6-20 mg/dl
CREATINE : creatinine level of greater than 1.2 for women and greater than 1.4 for men
BUN and creatinine levels that are within the ranges established by the laboratory performing the test suggest that your kidneys are functioning as they should. Increased BUN and creatinine levels may mean that your kidneys are not working as they should.
Abnormally high levels of creatinine thus warn of possible malfunction or failure of the kidneys.
Note also the electrolyte values show a diminished capacity of her kidneys to regulate acid-base balance.
The early acidosis we see here is due to the kidney's inability to secrete excess hydrogen ions and conserve bicarbonate, the body's key buffering substance. Another concern the physician will have been the patient's potassium level is above normal.
As hydrogen ions increase, intracellular potassium (K+) moves to the extracellular fluid and serum K levels rise. This condition is called hyperkalemia and poses a danger of disrupting the heart's conduction system. Hypernatremia, which is the retention of sodium (Na+), is a major factor in the fluid retention seen in this patient.
Sodium 134-143 mEq/L patients value 152 mEq/L
your kidneys wish to maintain a specific sodium-to-water ratio in your body. To do so, they hold on to extra water to compensate for the extra sodium you ate. This increased water retention may result in swelling, especially in the hands and feet, and can cause you to weigh more than usual
Since albumin helps to maintain blood volume in the blood vessels, a reduction of fluid in the blood vessels occurs. The kidneys then register that there is depletion of blood volume and, therefore, attempt to retain salt. Consequently, fluid moves into the interstitial spaces, thereby causing pitting edema.
Glycosuria is a condition in which a person's urine contains more sugar, or glucose, than it should. It typically occurs due to high blood sugar levels or kidney damage. Glycosuria is a common symptom of both type 1 diabetes and type 2 diabetes.
After formation, casts are loosened from the tubules and discharged into the urine
The lab will check your urine for albumin. Albumin is a type of protein that is normally found in your blood. Having albumin in your urine (three positive results over three months or more) is a sign of kidney disease.
