Exam 3: Renal 1/2 Flashcards
What are the roles of the kidney?
- Excreting metabolic wastes
- Maintaining extracellular fluid
- Maintain electrolytes
- Maintain acid-base balance
- Hormonal functions
Due to hepatic displacement, the right kidney’s position is ______ than the left kidney
slightly lower
A longitudinal section of the kidney reveals two distinct regions, the outer ____ and the inner _____
cortex; medulla
The medial margin of the kidney is concave because of the presence of a recessed fissure known as the ___.
hilus
Hilus lies at approximately what level?
L1
Parasympathetic innervation to the kidneys is via the ____
Vagus nerve
Sympathetic innervation to the kidneys is via the ____
T8-L1 preganglionic
Sympathetic innervation to the bladder is from _____ and controls what functions?
T11 – L2
Pain, touch, temp
Parasympathetic innervation to the bladder is from _____ and controls what functions?
S2-S4
Stretch, motor
The functional unit of the kidney is the ____
nephron
Production of urine begins with water and solute filtration from plasma flowing into the glomerulus via the _________
AFFERRENT arteriole
What are the 2 major determinants of GFR?
- Glomerular capillary pressure (arterial pressure)
- Glomerular oncotic pressure (renal blood flow)
The normal renal fraction of cardiac output is approximately ______%
25%
Renal blood flow is regulated by what 2 things?
- intrinsic autoregulation
- neural regulation
Afferent arteriole vasodilation and myogenic mechanisms are responsible for ______
autoregulation
Myogenic reflex - pressure
GFR relatively constant with changes in MAP from _______
80-200 mmHG
______ reabsorbs 2/3 of filtered sodium
Proximal tubule
What part of the kidney reabsorbs about 65% of filtered water?
Proximal tubule
ADH is secreted by the ____
posterior pituitary gland
arterial _________ are activated when hypovolemia leads to a decrease in blood pressure
baroreceptors
What is released by atrium in response to increased stretch?
ANP
(Atrial natriuretic peptide)
Which renal vasodilator, produced in kidney, is stimulated as a result of
stress, renal ischemia, and HOTN?
Prostaglandin
S/Sx of Hyopnatremia
Symptoms rarely unless < 125mEq/L
S&S - anorexia, nausea, and lethargy to convulsions, dysrhythmias, coma, and even death due to osmotic brain swelling
If acute, risk of neurological complications higher; Treat to prevent cerebral edema and seizures
S/Sx of Hypernatremia
Serum level > 145mEq/L
Generally due to sodium gain or water loss (usually the latter)
Can cause dehydration of brain leading ; Symptoms from confusion to convulsions and coma
Causes, Symptoms and Treatment of Hypokalemia
Causes: Vomiting, diarrhea, drugs, hormones, renal abnormalities, insulin therapy, inadequate intake
S/Sx: electrocardiogram (ECG) changes (flattened T waves “no pot, no T,” U waves) and skeletal muscle weakness
Treatment: replacement (IV or PO)
Causes of Hyperkalemia
abnormal kidney excretion, abnormal cellular potassium release (i.e. cell lysis), or abnormal distribution between the intra- and extracellular space.
> 5.5 mEq/L
renal pain is linked to what dermatomes?
T10-L1 (sympathetic)
if doing neuraxial block for kidney surgery would want coverage from _____________
T8-L4
What is a normal GFR for a 70 kg male
125 mL/min
What is the primary site of reabsorption in the nephron?
PCT
What is the primary site of water movement in the nephron?
Descending loop (b/c that is where aquaporins are)
Renal blood flow⬇ = _____ glomerular filtration
⬇ (decrease)
Angiotensin II production causes what 3 things?
- renal efferent arteriolar vasoconstriction
- ADH release
- Aldosterone release
List exogenous nephrotoxins commonly found in hospital settings
Antibiotics
Anesthetic agents
NSAID
Chemotherapeutic
Contrast
List endogenous nephrotoxins commonly found in hospital settings
Increased Calcium
Uric acid
Myoglobin (Rhabdo)
Hemoglobin(hemolysis)
Bilirubin
Paraproteins
True or False. Prerenal azotemia is reversible if the underlying cause is corrected.
True
Oliguria is defined as a urinary flow rate less than __________.
0.5 mL/kg/hour
Causes of prerenal azotemia:
Absolute decrease
- Acute hemorrhage
- GI fluid loss
- Trauma
- Surgery
- Burns
Low Output syndromes
- Renal artery stenosis
- Relative decrease
- Sepsis
- Hepatic failure
- Allergic reaction
Causes of intrarenal azotemia:
Acute glomerulonephritis, Vasculitis, Interstitial nephritis (drug allergy, infiltrative diseases)
Acute tubular necrosis
- Ischemia
- Nephrotoxic drugs (aminoglycosides, nonsteroidal anti-inflammatory drugs)
- Solvents (carbon tetrachloride, ethylene glycol)
- Heavy metals (mercury, cisplatin)
- Radiographic contrast dyes
- Myoglobinuria
- Intratubular crystals (uric acid, oxalate)
Causes of postrenal azotemia:
Urinary outflow tracts obstructed
- Prostatic hypertrophy (PBH) or cancer of prostrate or cervix
- Bladder carcinoma
- Clot retention or nephrolithiasis
Risk factors for acute renal failure
- Co-existing renal dz
- CHF
- Advanced age
- Symptomatic CV disease
- Major operative procedures (CPB, AAA repair)
- Sepsis
- Multi-organ system failure
- Iatrogenic: inadequate fluid volume replacement, delayed tx of sepsis, nephrotixc drugs or dyes
- pre-existing renal insufficiency
- shock
What procedures are considered high-risk for leading to renal failure?
Renal vascularization
Aortic cross-clamping
Cardiopulmonary bypass
Urologic surgery
Transplantation
Trauma
What are nephrotoxins that can lead to renal failure?
Aminoglycoside antibiotics
Radiocontrast dyes
Nonsteroidal anti-inflammatory drugs
Complications related to renal failure
Neuro
- confusion, asterixis, somnolence, seizures
CV
- systemic HTN, CHF, pulmonary edema, cardiac dysrhythmias, may have dilutional anemia
GI
- anorexia, nausea, vomiting, ileus, GI bleeding
S/Sx of renal failure
Generalized malaise
S&S volume overload (dyspnea, edema, HTN)
Lethargic, nauseated, confused
Pulmonary edema, hypoxia, hyperkalemia, acidosis
Encephalopathy (coma, seizures and death)
What is the most reliable measure of kidney function?
creatinine clearance
