NU 327 Renal Disorders (Exam 3)
Functions of the renal system - ANS-a. Maintain fluid, electrolyte, and acid-base balance
b. Detoxifying the blood and eliminating wastes
c. Glucose homeostasis-the excess will be filtered out through the kidneys
d. Regulating blood pressure
e. Production of erythropoietin-RBC produced by the bone marrow
f. Activation of Vitamin D to facilitate absorption of calcium
Normal anatomy of the Renal System - ANS-
What is a nephron? How many are there? - ANS-Functioning unit of the kidney
There are about 1 million in each human kidney
What are the 3 major functions of the nephron? - ANS-1. FILTRATION of water-soluble
substances from the blood
2.REABSORPTION of filtered nutrients, water, and electrolytes
3. SECRETION of waste products
What are the parts of the Nephron? - ANS--Glomerulus
-Proximal Convoluted Tubule
-Loop of Henle
-Distal Convoluted tubule
-Collecting Tubule
Glomerulus Function - ANS--Site of fluid filtration from blood to the nephron
-more permeable than other capillaries in the body
-PREVENTS PASSAGE OF BLOOD CELLS AND PROTEINS
-Blood in the urine (Hematuria) is an indication that something is wrong with the glomerulus
-HYDROSTATIC PRESSURE-is the driving force
-IMPORTANT FACTOR-blood volume
-GLOMERULAR FILTRATION RATE (GFR)=
90-120 ML/MIN (Normal)
-each glomeruli can regulate its own GFR
-Effective as long as systolic BP is 75-160
-Creatinine clearance is a good measure of GFR
Proximal Convoluted Tubule - ANS--Reabsorbs about 60% of the filtered water and electrolytes
-Reabsorbs all of the nutrients, glucose, amino acids, bicarbonate ions, and vitamins
,*Things start to get reabsorbed back into the bloodstream
Loop of Henle - ANS--Urea is secreted into tubule fluid
-Descending loop
*Transports water
*Delivers concentrated filtrate to ascending loop
-Ascending loop
*Actively transports Na+, Cl-, K+
-Increased interstitial osmolarity
Distal Convoluted Tubule - ANS--"Fine Tune" of sodium and water reabsorption
*Aldosterone (holds onto more sodium and water)
-Secretes H+ and K+
-Site from which filtrate enters the collecting tubule
Collecting Tubule - ANS--Distal tubules empty into the single larger collecting tubule
-Responds to antidiuretic hormone (ADH)
-Regulates secretion of acid
-Merges into the larger collecting ducts
-More than 99% of the original filtrate is reabsorbed by the time it reaches the renal pelvis.
CREATING 30-60 ML OF CONCENTRATED URINE PER HOUR.
What hormones are important in regulation of kidney function? - ANS-1. Angiotensin II
A. Major stimulus:
-Increased renin, decreased BP
B. Nephron site of action:
-Proximal tubule, (TAL) loop of henle, Distal tubule/collecting tubule
C. Effects on transport:
- Increases NaCl and H2O reabsorption
2. Aldosterone
A. Major Stimulus:
- Increased angiotensin II, increased K+
B. Nephron site of action
-Loop of henle(TAL), distal tubule/collecting tubule
C. Effects on transport
- Increased NaCl and H2O reabsorption
3. Sympathetic nerves
A. Major stimulus
-Decreased extracellular fluid volume, decreased BP
B. Nephron site of action
, -Proximal tubule, Loop of henle(TAL), distal tubule/collecting tubule
C. Effects on transport
-Increased NaCl and H2O reabsorption
4. ADH(antidiuretic hormone)
A. Major stimulus
-Increased plasma osmolality, decreased extracellular fluid volume
B. Nephron site of action
-distal tubule/collecting tubule
C. Effects on transport
-Increased H2O reabsorption
Which labs are important in the assessment of kidney function? - ANS-1. Blood urea
nitrogen(BUN)
a. normal value: 5-20mg/dl
b. indirect measure of overall hydration
c. also, can reflect diet, hydration, GI bleeding, and tissue breakdown
2. Creatinine-more specific
a. normal value: 0.5-1.5 mg/dl (slightly higher in men)
b. reflects GFR
c. most commonly used 'quick' method to estimate renal function in actual patients
3. Urinalysis
a. Normal urine: clear, odorless, pale yellow to amber, slightly acidic, may contain a few cells
What does costovertebral angle (CVA) tenderness tell you about the kidneys? - ANS--Sign of
kidney infection
Describe the age related changes to kidney function - ANS--Diminish in size and function by 4th
decade
-Decreased glomeruli
-By age 70: 30-50% of glomeruli lost
-Renal blood flow decreases
-Less renal reserve
More susceptible to fluid and electrolyte imbalances
-Susceptible to damage from drugs, medications, and contrast media
Glomerulonephritis
(PHARM PHLASH) - ANS-Clue: Diagnostic and Clinical findings
Hypertension; oliguria; smoky, frothy urine. Urinalysis shows RBCs, casts, and protein
Acute Glomerulonephritis - ANS-A. Etiology&Risk Factors:
1. More common in men
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