Exam #1 Renal Flashcards
Renal
How much do the Kidneys Filter?
Equivalent to all the bodys ECF ( 15 L ) every 100 mins
Kidneys are able to make?
Adjustments to fluid volume
Electrolyte Composition
Acid Base Balance
Kidneys secrete what hormone?
Renin, which plays a role in regulating blood pressure
Erythropoitentin which stimulates RBC production
Kidneys are responsible for the production of
Calcitriol, the active form of Vit D which allows us to absorb calcium from our diet
Blood enters the nephrons through the?
Large renal arteries and is filtered through the glomerulus, a specialized capillary. —> Bowmans Capsule and then –> proximal tubule
Once in the nephron the fluid is called?
Filtrate, what will eventually become Urine
Proximal Tubule –>
Loop of Henle —> Distal Tubule –> Common Collecting Ducts –> Kidney
Should protein be in urine?
NO
Water Soluble Drugs
Are easily excreted by the kidneys
Charged / ionized substances
Also easily excreted ( K+, Mg+, Cl-, Na+, Ca+ )
How does the liver help with excretion?
By making lipid soluble drugs more water soluble so they can be removed by the kidneys.
Kidneys also filter into urine…
Excess amino acids, glucose, bicarbonate ions, hydrogen ions
Normal Blood Glucose Level
70-130 mg/dl
Proximal Convoluted Tubule
A loop like structure of the kidney, reabsorbs 98% of glucose back into blood.
- Only when blood glucose level is normal
At blood glucose levels beyond 300 mg/dl
The proximal tubule fails to reabsorb the filtered glucose and the glucose will start spilling into the urine.
When kidneys are damaged…
Reabsorption and secretion mechanisms are impaired and serum drugs levels may be affected. ( Reduce dosage and frequency )
Normal pH level
7.35-7.45
If the serum level is too acidic then the pH number will be
Low
If the serum level is too alkaline then the pH number will be
High
Causes of Metabolic Acidosis
GI bicarbonate losses ( diarrhea )
Lactic Acidosis ( Sepsis, Hypoperfusion, metformin overdose )
Renal Failure leading to Uremia
Causes of Respiratory Acidosis
COPD
Asthma Attack
Cardiac Arrest ( CO2 Build Up )
Depression of respiratory center
Causes of Metabolic Alkalosis
Vomiting
NG Suction
Too much sodium bicarbonate
Causes of Respiratory Alkalosis
Hyperventilating
2 mechanisms to remove acid:
- The CO2 produced during body metabolism is an acid efficiently removed by the lungs during exhalation
- The kidneys remove excess acid in the form of hydrogen ions by excreting them in the urine. Kidneys can retain bicarbonate from the renal tubules
If retained in the body, CO2 and H+ would
Lower body ph thus the lungs and kidneys collaborate in the removal of acids to maintain normal acid base balance
Lungs play a vital role in…
Acid-Base Balance
- CO2 and acid is removed by the lungs during exhalation.
- When CO2 elimination is inadequate the retained CO2 will drive the release of acid hydrogen ions, the arterial blood becomes more acidic and this is called respiratory acidosis.
When hyperventilation occurs, and more CO2 is eliminated than normal… arterial blood becomes
Alkalotic, known as respiratory alkalosis.
Kidneys play a vital role in…
Acid-Base Balancing
- They excrete hydrogen ions and retain bicarbonate ions when hydrogen ions become too high.
- They retain hydrogen ions and excrete bicarbonate when hydrogen levels fall below norma.
When the excretion of hydrogen ions and retention of bicarbonate ions is not enough to eliminate the excess hydrogen ions in the body…
Arterial blood becomes acidic known as metabolic acidosis.
Eg; Renal Failure
If hydrogen ions are not maintained in the normal range ( too low ) or too abundant
Metabolic alkalosis occurs
Eg; Vomiting
What to do for acidotic patients?
To infuse sodium bicarbonate
( neutralizes acid in blood )
- BUT need to find cause! Just a “band-aid”
What to do for alkalotic patients?
Infusions of normal saline, concurrently with potassium chloride.
- Increases renal excretion of bicarbonate ions, which increases the acidity of blood by eliminating the acid buffer from blood.
For patients who can’t tolerate extra fluid?
Fluid overload patients –>
Hydrochloric acid and ammonium chloride are 2 drugs that can quickly lower pH in patients.
ABG
Arterial Blood Gases
A clinical test that involves measurement of the pH of arterial blood and the amount of oxygen, CO2, and bicarbonate dissolved in arterial blood.
- Monitored in critically/acutely ill patients.
In the presence of respiratory acidosis
( retaining CO2 )
The kidneys compensate by excreting H+ ions and retaining bicarb ions.
- pH levels become normal and bicarb ions rise.
Compensation by the kidneys…
Is not quick, may take several hours for compensation to become noticeable and up to 4 days to be complete.
In the presence of respiratory alkalosis
The kidneys compensate for the increase in pH by retaining hydrogen ions and excreting bicarb ions.
In the presence of metabolic acidosis
Ventilation of the lungs increases through stimulation of central chemoreceptors in the medulla of the brain and peripheral chemoreceptors in the carotids and aortic arch- the CO2 levels fall and the equation is pushed to the left and the hydrogen concentration falls.
Metabolic Alkalosis
Is hypoventilation in which CO2 rises above normal- but respiratory compensation of metabolic alkalosis is variable and unpredictable. it is unlikely that a conscious patient will hyperventilate.
CO2 forms
H+ ions when retained by the body, leading to acidosis
What causes too much bicarb?
H+ shifting