Chemistry Exam 1 Flashcards
The proximal convoluted tubule (PCT) reabsorbs
Glucose, Amino acids, Proteins
Disease state: High ADH
Inappropriate ADH Secreation
Disease state: Low ADH
Diabetes insipidus
ADH is secreted when
- high plasma sodium
- low plasma water
ADH causes what effect to happen where
Water reabsorption to increase in the Collecting Ducts of the Kidneys
Osmolality
Measure of osmotic pressure across body membranes
Osmolarity
Measure of osmoles of solute (dissolved particles) per kilogram of solvent
When are osmolality and osmolarity equivalent?
When the solvent is water, like in the body
Formula 1 for Osmolality
2.0[Na+] + [glucose]/20 + [BUN]/3
Units for Osmolality formula
[Na] in mEq/L
[Glu] and [BUN] in mg/dL
Osmolar Gap - definition and significance
- Difference between calculated and measured osmolalities
- May indicate unaccounted for solutes, most commonly alcohol, mannitol, glycine, methanol, or ethylene glycol
- Larger gap = poorer prognosis
Colligative Properties
More dissolved particles causes:
- Freezing point down
- Vapor pressure down
- Boiling point up
- Osmotic pressure up
1000 mOsmole results in how much freezing point depression?
1.86 °C
What are the body’s fluid compartments? What do they include?
- Intracellular Fluid Compartment (ICF) - fluid within cells
- Extracellular Fluid Compartment (ECF) - plasma and interstitial spaces
Creatinine Clearance formula
UV/P x 1.73/A
Renal threshold for glucose
160-180 mg/dL
Classifications of Renal Disease
- Pre-renal (cardiac output)
- Renal (kidneys)
- Post-renal (blockage like stones or tumors)
Non-protein Nitrogen (NPN) compounds
- BUN
- Uric Acid
- Creatinine/creatine
- Ammonia
Increase in one more more NPN is called
Azotemia
Creatinine vs Creatine for disease states
- Creatinine = Renal Disease
- Creatine = Muscular Disorders
Jaffe Reaction
Detects creatinine by color formation as it complexes with alkaline picrate
Ornithine Cycle
Ammonia from protein degradation is converted to BUN, which is soluble for excretion in urine
How are azotemia and uremia related?
- Azotemia is high BUN in plasma
- Uremia is high BUN in urine (renal failure)
High BUN occurs in
- Low Renal Perfusion
- Renal Disease
- High Protein Intake
- Dehydration
Low BUN occurs in
- Low protein intake
- sever liver disease
- Sever vomiting or diarrhea
Urease converts
Urea to ammonia
Berthelot reaction
Detects BUN indirectly by converting to ammonium with urease, then reacting with phenol. Indophenol is produced, which is a blue chromophore.
BUN Enzymatic Assay
Detects BUN indirectly by converting to ammonium with urease, then reacting with enzyme to convert NADPH to NADH. NADPH is more colored than NADH, so more BUN = less color in the products.
BUN Chemical Method
Urea reacted directly with diacetyl. Produces diazine chromaphore.
BUN:Creatinine Ratio
- Healthy = 10:1 to 20:1
- Pre-renal azotemia = 20:1 to 30:1
- Post-renal azotemia =»_space;20:1 with high creatinine (proportional increase)
- Low BUN from liver disease or malnutrition = <10:1
Uric Acid Chemical Method
Uric Acid + Phosphotungstic acid to make Tungsten blue
Uric Acid Enzymatic Method
Uricase converts uric acid to allantoin and peroxide. Peroxide reacts with NADP to make NADPH chromagen
What organ converts ammonia to BUN?
Liver
Ammonia Methodology
Ion Selective Electrode
“Lytes” includes
- Na+
- K+
- CL-
- HCO3-
Major Extracellular Cation
Sodium
Where is Aldosterone produced? What does it control?
- Produced in adrenal gland
- Sodium reabsorption in kidneys
Disease State: low aldosterone
Addison’s Disease
Disease State: high aldosterone
Cushing’s Disease
Name and Function of ACE
- Angiotensin Converting Enzyme
- Converts Angiotensin I to Angiotensin II
What activates the renin-angiotensin system? What is the result of this activation?
- Juxtaglomerular Apparatus
- Increase to blood pressure and sodium levels
Major Intracellular Cation
Potassium
Low Potassium is caused by
- low intake
- insulin excess
- vomiting or diarrhea
Potassium Critical Values
<2.8 or >6.0 mmol/L
High Potassium is caused by
- high intake
- tissue destruction
- hemolysis of sample
- impaired renal excretion
Major Extracellular Anion
Chloride
Cl- ion shift
is secondary to Na+ and HCO3- movement in and out of cells
Low Chloride is associated with
- prolonged vomiting
- skin trauma/burns
- renal lost to diuretics
- metabolic acidosis
High Chloride is associated with
- dehydration
- renal tubular acidosis
- loss of NaHCO3
- salicylate intoxication (aspirin)
Equation for equivalence of H2CO3 to pCO2 in the blood
H2CO3 = 0.03 x pCO2
Sweat Chloride Testing
- Screening test for cystic fibrosis (high in these patients)
- Measured with pilocarpine iontophoresis
2nd largest anion in the ECF
Bicarbonate (HCO3-)
Control of HCO3- levels happens in
- Kidneys through reabsorption
- Lungs through respiration rate
Low HCO3- results in
Metabolic Acidosis
High HCO3- results in
Metabolic Alkalosis
Anion Gap formula
[Na+] - ([Cl-] + [HCO3-])
The body pH centerpoint is
7.4
The Krebs Cycle produces
ATP + H2O + CO2 (acid)
What cation moves with HCO3-?
Na+
Bicarbonate Buffer System Equillibrium
CO2 + H2O <-> H2CO3 <-> HCO3- + H+
Phosphate Buffer System Equillibrium
(HPO4)2- + H+ <-> (H2PO4)-
Effect of Acidosis on CNS
Suppression
Effect of Alkalosis on CNS
Excitation
pKa of Bicarbonate
6.11
Where is the respiratory center of the brain?
Hypothalmus
Respiratory Acidosis
Increased pCO2
- issues breathing
- barbiturate poisoning
- brain damage
Metabolic Acidosis
Decreased bicarbonate
- loss to diarrhea
- ethylene glycol/methanol poisoning
- decreased kidney function
Respiratory Alkalosis
Decreased pCO2 from hyperventilation
- oxygen deficiency
- anxiety
- aspirin overdose
- brain damage
Metabolic Alkalosis
Increased bicarbonate
- Loss of acid (vomiting)
- Cushing’s Disease
- Citrate toxicity from massive transfusion
A patient is compensating for acid/base imbalance if
- they are within the reference range
- the levels of pCO2 and HCO3- are on the same side of normal (both high/both low)
Respiratory Compensation
- occurs in minutes, maxed within hours
- can’t handle long-term stress
Metabolic Compensation
- occurs in hours, maxed within days
- better handles long-term stress