Genitourinary System Flashcards
What are the functions of the kidneys?
Create urine Rid the body of waste in the form of urine: urea, bacterial toxins, water-soluble drugs, drug metabolites Excrete or conserve fluid Keep electrolytes balance Acid-base balance Activate vitamin D Produce erythropoietin Produce renin (for RAAS) Regulates blood pressure
What is the purpose of the kidneys activating vitamin D?
Vitamin D must be in its active form so that the body can absorb calcium
What type of calcium imbalance is present when there is decreased renal function? Why?
Hypocalcemia
The kidneys cannot activate vitamin D
Without the active form of vitamin D, calcium cannot be absorbed
What is the purpose of erythropoietin?
Erythropoietin stimulates the bone marrow to produce red blood cells
What blood condition is present when there is decreased renal function?
Anemia
The kidneys are not producing erythropoietin. Bone marrow is not stimulated to make red blood cells
When is erythropoietin production increased? Why?
Living at an increased altitude
COPD
There is a lack of oxygen within the body/blood stream. The body produces more red blood cells so there will be more hemoglobin available to carry oxygen. To make more red blood cells, erythropoietin production is required by the kidneys.
What conditions will activate RAAS?
Decreased renal perfusion Decreased blood pressure Decreased extracellular fluid (intravascular volume) Decreased serum sodium Increased urine sodium
What is the end production of RAAS?
Aldosterone causes vasoconstriction of the arteries, thus increasing blood pressure
Aldosterone causes the kidneys to increase sodium retention, water follows. Extracellular fluid increases, which increases blood pressure
What labs assess kidney function?
BUN
Creatinine
eGFR
Creatinine Clearance (aka Glomerular Filtration Rate)
What diagnostic test is the best indicator of kidney function?
Creatinine Clearance (aka Glomerular Filtration Rate)
What is the normal range for Creatinine Clearance (aka Glomerular Filtration Rate)?
About 120 mL/min
What does Blood Urea Nitrogen measure?
BUN measures the amount of urea nitrogen within the blood
Urea-nitrogen is a waste by product of protein
What does Creatinine measure?
The amount of creatinine within the blood
Creatinine is a waste by product of creatine
Which lab is more indicative of kidney function? BUN or Creatinine? Why?
Creatinine. Creatinine solely measures kidney function
BUN can be elevated for non-kidney related issues (example: high protein diet)
What does aldosterone do?
Aldosterone acts on the kidneys to retain sodium. Water follows.
Sodium and water are reabsorbed into the body
Potassium is excreted into the filtrate/urine
What does Antidiuretic Hormone (ADH) do?
Promotes the reabsorption of water from the filtrate into the body
What does Atrial Natriuretic Hormone do?
Blocks aldosterone when the atria are stretched / fluid overloaded
What does Parathyroid Hormone (PTH) do?
Promotes the reabsorption of calcium from the filtrate into the blood
Excretes phosphate into the filtrate/urine
What is the normal amount of urine production in 24 hours?
1,000 mL - 2,000 mL
What is the normal specific gravity of urine?
1.005 to 1.030
If specific gravity is low (less than 1.005), what does that tell us?
The urine is very dilute
There is more fluid in the urine than waste/particles
The person may have increased their fluid intake
The person may be taking a diuretic
If specific gravity is high (greater than 1.030), what does that tell us?
The urine is very concentrated
There is more waste/particles than fluid
The patient may be dehydrated
How does aging affect the kidneys?
Decreased ability to concentrate urine
Glomerular filtration rate decreases
Number of nephrons decrease
How does aging affect the bladder?
Decrease bladder size and muscle tone. This causes: Dysuria Increased frequency Incontinence Urine retention
