Renal System Flashcards
Exam 3
Renal system overview
Kidneys receive what percent of cardiac output?
Kidneys receive 21% of cardiac output
Renal system overview
Kidneys process how much blood per minute?
The kidneys process 1.2 L of blood per minute
Renal system overview
The entire blood volume is filtered through what? How many times a day?
The entire blood volume is filtered through the kidneys 340 times a day
Renal Anatomy
Kidneys are made up of what?
Nephron
Renal Anatomy
Nephrons are composed of?
Glomerulus
Bowman’s capsule
Tubular system
Renal Anatomy
Glomerular Filtration Rate (GRF): What is it?
Rate at which filtrate is formed
Renal Anatomy
Glomerular Filtration Rate (GRF): What does it do?
Autoregulation”
Renal Anatomy
Glomerular Filtration Rate (GRF): What do afferent arterioles do?
Afferent arterioles adjust diameter in response to the pressure of blood coming to them.
Renal Anatomy
Glomerular Filtration Rate (GRF):
Afferent arterioles adjust diameter in response to the pressure of blood coming to them.
During hypotension:
the smooth muscles of the afferent arterioles relax, vasodilation occurs, and perfusion increases, thereby maintaining the GFR at its normal rate.
Renal Anatomy
Glomerular Filtration Rate (GRF):
Afferent arterioles adjust diameter in response to the pressure of blood coming to them.
During hypertension:
vasoconstrict to decrease perfusion
Renal Anatomy
Glomerular Filtration Rate (GRF):
In healthy persons, autoregulation maintains homeostasis quite nicely when mean blood pressure falls approximately within a range of what?
In healthy persons, autoregulation maintains homeostasis quite nicely when mean blood pressure falls approximately within a range of 80 to 180 mm Hg
Renal Anatomy
Proximal tubules: What do they do?
80% filtrate returned to bloodstream by reabsorption in the proximal tubule
Renal Anatomy
Proximal tubules: What do they reabsorb?
All the glucose and amino acids
Much of sodium, chloride, hydrogen, and other electrolytes
Renal Anatomy
Proximal tubules: What do they secrete?
The proximal tubule cells also secrete substances (e.g., some drugs, organic acids, and organic bases) into the filtrate.
Hormonal Influence includes
ADH
Renin
Aldosterone
Hormonal Influence:
ADH: Where are osmoreceptors? What are they sensitive to?
Osmoreceptors in hypothalamus sensitive to serum osmolality
Hormonal Influence:
ADH: What would stimulate release of ADH?What does this lead to?
During dehydration, when serum osmolality rises, osmoreceptors in the hypothalamus respond by stimulating the hypothalamus to secrete ADH which increases the permeability of collecting tubule cells to water.
Hormonal Influence:
ADH: During dehydration, when serum osmolality rises, osmoreceptors in the hypothalamus respond by stimulating the hypothalamus to secrete ADH
which increases the permeability of collecting tubule cells to water.
Hormonal Influence
ADH: What does it do?
This permits the reabsorption of water alone (without electrolytes), which in turn decreases the concentration of the ECF.
Hormonal Influence
Renin: What is it secreted by?
Secreted by juxtaglomerular cells
Hormonal Influence
Renin: How does it effect GFR?
Angiotensin II constricts the smooth muscle surrounding the arterioles. This increases blood pressure, which increases the GFR.
Hormonal Influence
Aldosterone: What triggers the release of this? What is it released from?
Triggered by angiotensin II
Adrenal cortex
Hormonal Influence
Aldosterone: What does it do? How?
By increasing sodium reabsorption in distal tubule cells, aldosterone causes an increase in renal water reabsorption.
Hormonal Influence
Aldosterone: By increasing sodium reabsorption in distal tubule cells, aldosterone causes an increase in renal water reabsorption. What does this lead to?
This increases blood pressure and decreases serum osmolality.
Functions of the Renal System include
Renal clearance
Regulation
Fluid balance
Secretion of hormones
Functions of the Renal System:
Renal clearance: What is cleared? How much?
Clearance of metabolic end products
About 60 mL of plasma “cleared” of urea/minute
Functions of the Renal System
Regulation:
Electrolyte concentrations and pH of the extracellular fliud
Functions of the Renal System
Secretion of hormones: Like what?
Calcitrol and erythropoietin
Slide 9/10
Assessing for Excessive Volume include:
Hypertension, pulmonary edema, crackles
Elevated neck veins, liver congestion and enlargement
Heart failure and shortness of breath
Pitting edema of the feet, ankles, hands, and fingers
Periorbital edema, sacral edema, ascites
Assessment of Urine
What are you assessing for?
Assess for color, clarity, and odor
Assessment of Urine
What is normal?
Normal: clear and yellow to straw-colored (pale yellow);
smells of ammonia
Assessment of Urine
What is abnormal? What may indicate infection?
Being cloudy may indicate infection.
Blood in urine (hematuria) may appear bright red or dark brown
Assessment of Urine
Urine Volume:
What causes acute anuria?
Complete bilateral obstruction
Glomerulonephritis
Bilateral vascular occlusion
Laboratory Studies: Urinalysis
What is included?
Urine pH
Urine protein
Urine glucose
Urine ketones
Urinary sediment
Laboratory Studies: Urinalysis
Urine pH: What is the normal range?
Normal range between 5.0 and 6.5
Laboratory Studies: Urinalysis
Urine pH: pH greater than 7.5 (alkaline urine) suggests what?
pH greater than 7.5 (alkaline urine) suggests urinary tract infection.
Laboratory Studies: Urinalysis
Urine pH: pH less than 5.0 may indicate
pH less than 5.0 may indicate kidney compensating serum acidosis.
Laboratory Studies: Urinalysis
Urine protein: normal?
Normal: 0 to trace
Laboratory Studies: Urinalysis
Urine protein: Proteinuria usually indicates?
Proteinuria usually indicates damage to kidneys.
Laboratory Studies: Urinalysis
Urine glucose: What is normal?
Normal: negative
Laboratory Studies: Urinalysis
Urine glucose: glucosuria?
Glycosuria if serum glucose greater than 200 mg/dL
Laboratory Studies: Urinalysis
Urine ketones: normal?
Normal: negative
Laboratory Studies: Urinalysis
Urine ketones: abnormal?
Ketonuria indicates DKA.
Laboratory Studies: Urinalysis
Urinary sediment: refers to what?
Refers to casts, red cells, white cells, epithelial cells, and crystals
Laboratory Studies: Urinalysis
Urinary sediment: Red blood cells
Red blood cells (hematuria)
Laboratory Studies: Urinalysis
Urinary sediment: Red blood cells
What are examples of external sources?
External source (kidney stones, trauma, prostatic disease)
Laboratory Studies: Urinalysis
Urinary sediment: Red blood cells
What can cause rbcs in urine?
Glomerular diseases
Laboratory Studies: Urinalysis
Urinary sediment: Myoglobin
How can it make the urine appear?
Myoglobin in the urine makes the urine appear red; however, when the urine is inspected under the microscope, there is no evidence of RBCs
Laboratory Studies: Urinalysis
Urinary sediment: White blood cells (pyuria)
What does it indicate?
Pyuria usually indicate infection.
Laboratory Studies: Urinalysis
Urinary sediment: Myoglobin
What is it caused by?
Caused by skeletal muscle breakdown
Diagnostic assessment
Labs include:
Urinalysis
pH
Specific Gravity
BUN/Creatine
Diagnostic assessment
Labs include: Abnormal things
Protein
Glucose
Sediment
RBC/WBC
Diagnostic assessment
Labs include: BUN/Creatine
Creatinine amount of blood cleared of creatinine in 1 minute
Diagnostic assessment
Labs include: BUN/Creatine
What is the normal amount?
normal- 0.6-1.2 mg/dL
Diagnostic assessment
Labs include: BUN/Creatine
When would BUN be high?
BUN higher if dehydrated, too much protein intake, or from protein breakdown (i.e crush injuries)
Diagnostic assessment
Labs include: BUN/Creatine
What is normal BUN values?
Normal 8-20 mg/dL
Increased BUN may have other causes
Such as?
Increased protein intake
Increased tissue breakdown
Febrile illnesses
Steroid or tetracycline administration
Reabsorption of blood from the intestine
Dehydration
Shock, heart failure
Increased BUN may have other causes
When are patients symptomatic?
Patients are symptomatic when osmolality is greater than 350 mOsm/kg
Diagnostic Studies
Include?
Radiologic studies
Renal biopsy
Renal angiography
Diagnostic Studies
Renal biopsy: What are contraindications to this?
Contraindications include serious bleeding disorders, severe obesity, and severe hypertension.
Diagnostic Studies
Renal angiography:
Assess renal vasculature with ultrasonography
Dialysis:
All forms of dialysis use the principle of what? To do what?
All forms of dialysis make use of the principles of osmosis and diffusion to remove waste products and excess fluid from the blood.
Dialysis:
What is present in the dialysis circuit?
Semipermeable membrane is in the dialysis circuit between the blood and the dialysate.
Dialysis:
How do dissolved substances move?
Dissolved substances, such as urea and creatinine, diffuse across the membrane from an area of greater concentration (blood) to an area of lesser concentration (dialysate).
Dialysis:
Diasylate: has what?
Dialysate has varying concentrations of dextrose or sodium to produce an osmotic gradient, pulling excess water from the circulatory system.