Renal System Flashcards
Function of Kidneys
Eliminates waste products of metabolism
Acid-base balance: exreting H+ when there is excess acid
Regulation of arterial blood pressure: by adjusting Na excretion
Regulates plasma volume and osmolality: osmotic pressure by excreting osmotically dilute or concentrated urine
Regulate concentrations of several ions in blood plasma; including all electrolytes.
Eliminates many drugs
Hormone production: EPO
Vitamin D activation
Enzyme: renin production for BP control
Nephron?
functional unit of kidney -1.2 million in each kidney Each nephron has 2 parts; glomerulus and tubules
Glomerulus
cluster of branching capillaries
Cup shaped membrane at the head of each nephron forms the bowman’s capsule
Filters waste products from blood
Tubules
Proximal tubule
loop of Henle
Distal tubule
Collecting tubule
Nephron blood supply?
Blood flows to the glomerulus by afferent arterioles
Leaves glomerulus by efferent arterioles
Follows nephrons in peritubular capillaries
What is the main function of the glomeruli
Ultrafiltration
How is filtration based on size and charge?
Small solutes cross readily
larger substances are generally restricted
Negatively charged molecules are restricted
99% water reabsorbed- 1-1.5L urine excreted
Regulation of h20 homeostasis
The large concentration gradient between the inner medulla and outer cortex allows the kidney to excrete urine
Solute load?
Represents the end waste products of normal metabolism
GFR
Glomerular filtration rate: the rate at which substances are cleared from plasma.
Urine albumin: first signs of renal insufficiency
Calculate GFR
amount of filtrate formed per minute based on total surface area available for filtration (# of functioning glomeruli)
Can be calculated from serum creatinine using standard eq
Can be determined also by using injected isotop (inulin) measurement in 24 hr urine collection
Normal GFR
> 60mL/min/1.73m2
Daily fixed load:
600 mOsm
Minimum Urine volume capable of eliminating daily fixed 600mOsm
500mL
Oliguria
<500 mL/d
Two key markers for CKD?
Urine albumin
eGFR
Current accepted “normal” level of albumin in urine
<30 mg/g
Nephrone functions to maintain balance:
Filtration
Reabsorption
Secretion
BUN
Normal level 8-20 mg/dL
Common Kidney Diseases
Edema HTN Metabolic acidosis Hyperkalemia Microcytic anemia and iron def Uremia Azotemia (nitrogenous waste product acumulation) Oliguria Hyperphosphatemia
CKD
Chronic Kidney Disease
syndrome of progressive and irreversible loss of functions secondary to kidney damage
Excretory, endocrine, metabolic
Most common CKD:
Diabetic nerphorpathy High BP PKD Polycystic kidney disease Acute Renal Failure Chronic Renal Failure End Stage Renal Disease
Nephrotic Syndrome
Alterations of the glomerular basement membrane allows persistant loss of large amounts of protein in the urine.
Marked by def of albumin in blood and excretion of albumin in urine
Assoc w/ DM, etc
NS Pathophysiology
Proteinuria >3.5g per 1.73m2 of body surface per day
Hyperlipidemia: Possible reasons altered lipid metabolism High serum chol, TG, LDL, Normal or Low HDL, Reduced levels of lipoprotein lipase
Diseases that can result in NS:
DM nephropathy
infection/drug toxicitiy
autoimmune disease
Clinical manifestations of NS?
Frothy urine
Anorexia, malaise, puffy eyelids, ab pain, muscle wasting
Anascarca (generalized edema) with ascites
Altered BP
Oliguria d/t hypovolemia
Loss of minerals. Iron bound to protein lost
NS Treatment
Treat underlying cause Reduce chole Control BP- fluid retention Reduce protein in urine-protein controlled diet ACE inhibitors and ARBs Check K levels
Nephritic syndome
Acute glomerulonephritis (inflammation of glomerulus) Sudden onset often after strep infections Symptoms include hematuria, hypertension, usually resolve on their won or advance to nephrotic syndrome or ESRD
Acute Renal Failure (ARF)
when kidneys suddenly stop functioning and abrupt cessation over 24-48 hrs leading to reduction in GFR and accumulation of nitrogenous wastes
How does it happen?
Rapid, often reversible,
GFR declines over hours to days
Most commonly occurs during hospitalization
Assoc with major in hospital morbidity
Ischemic injury d/t loss of blood supply to kidneys
Nephrotoxic injury: medications, contract medium chemotherapy, poision
Multiorgan system failure
Sepsis
Obstructive uropathy
Acute glomerular nephritis
Phases of ARF
Prodromal phase: duration variable UO normal
Oliguric: 10-14 days- Output low
Postoliguric: average 10 days UP returns to normal
Recovery 1 month to one year
Hemodialysis (HD)
blood is circulated through a dialyzer (artificial kidney), where it is bathed by dialysate, a solution that selectively removes fluid and wastes
Peritoneal dialysis (PD)
dialysate is infused into a person’s peritoneal cavity, and blood is filtered by the peritoneum (the membrane that surrounds the abdominal cavity) – after several hours, the dialysate is drained, removing unneeded fluid and wastes
Internal arteriovenous (AV) fistula
A connection between two organs or vessels that normally do not connect. •An artery and vein are surgically connected
Access site
Continuous cyclic peritoneal dialysis (CCPD)
The machine automatically fills and drains the dialysate from the abdomen.
Schedule involves three to five exchanges during the night while the person sleeps.
During the day, the person performs one exchange
Cyclosporine
Cyclosporine is used to prevent organ rejection after a kidney, heart, or liver transplant
Grapefruit and grapefruit juice may interact with cyclosporine and lead to unwanted side effects. Avoid the use of grapefruit products while taking cyclosporine.
Prednisone
Prednisone is a corticosteroid. It prevents the release of substances in the body that cause inflammation. It also suppresses the immune system.
Spironolactone
Spironolactone is a potassium-sparing diuretic (water pill) that prevents your body from absorbing too much sodium and keeps your potassium levels from getting too low.
Drinking alcohol can increase certain side effects of spironolactone.
Do not use salt substitutes or low-sodium milk products that contain potassium. These products could cause your potassium levels to get too high while you are taking spironolactone.
Avoid a high-salt diet. Too much salt will cause your body to retain water, which may reduce the effectiveness of this medicine.
Neomycin
Neomycin is an antibiotic that fights bacteria in the body.
Neomycin is used to reduce the risk of infection during surgery of your intestines. Neomycin is also used to reduce the symptoms of hepatic coma.
If you are being treated for hepatic coma, avoid eating foods that are high in protein
Epoetin alfa
It is used to treat anemia.
It is used to help avoid the need for blood transfusions.
