acid/base liver Flashcards
what is a buffer made of?
weak acid + salt conjugate base (resist changes in pH when adding acid or base)
what is the formula for carbonic acid and bicarb? and under what conditions are each made?
carbonic acid: H2CO3
- made when there’s additional H+ ions in the body that add to bicarb
bicarb: HCO3-
- made when a strong base is added: carbonic acid joins with OH- to make H2O and the subsequent weak conjugate base (bicarb) is made
what is the henderson-hasselback equation?
pH = pKa + log(A-/HA)
where pKa is assumed 6.1
What is the relationship between carbonic acid and partial pressure of CO2? (used in the HH equation)
H2CO3 = pCO2 x 0.03
so in the equation, pH = pKa + log[(bicarb/(pCO2 x 0.037)]
in the tissues, CO2 diffuses _____ of the tissues and _____ plasma and RBCs. What then diffuses out of the RBCs, and what goes into the RBCs?
CO2 out of tissue and into plasma and RBCs
then bicarb diffuses out of the RBCs and chloride diffuses into the RBCs
in the lungs, ____ diffuses from alveoli into blood where it binds to Hgb. What happens to bicarb? Then what?
in the lungs, oxygen diffuses from alveoli into blood where it binds to Hgb.
Bicarb binds with hydrogen ions to make carbonic acid
then carbonic acid dissociates into H2O and CO2 so then the CO2 can leave through alveoli/ventilation
what are the kidneys main role in the acid-base balance, and how does it do this?
its main role is to reabsorb bicarb from filtrate.
- bicarb is reabsorbed using Na+ in exchange for H+.
- increased pH limits Na+/H+ exchange, which limits bicarb reabsorption
- and decreased pH increases the Na+/H+ encage, leading to more bicarb reabsorption
acid-base disorder compensation is done by the _____ and ______. Which is associated with pCO2, and which is associated with HCO3-? The compensation is done by the organ ______ assisted with the primary process
kidneys: HCO3-
lungs: pCO2
compensation for a problem in the kidneys is done by the lungs, and vice versa
how fast are the lungs and kidneys when responding to an acid-base imbalance?
lungs: immediate compensate by retaining or expelling CO2 (short-term)
kidneys: take 2 -4 days to respond, but the affects are long-term and sustained
what are the four acid-base imbalances, and what is the primary defect of each?
repository acidosis: primary accumulation of pCO2
- with decreased pH
respiratory alkalosis: primary deficit of pCO2
- with increased pH
metabolic acidosis: primary deficit of HCO3-
- with decreased pH
metabolic alkalosis: primary accumulation of HCO3–
- with increased pH
what are causes for respiratory acidosis (increased pCO2)
ineffective removal of CO2 from blood
- Lung diseases: asthma, emphysema, bronchitis
airway obstruction
- COPD and intra/extra-pulmonary problems
depression of respiratory centers
- barbiturates, morphine, alcohol
decreased pulmonary circulation
- CHF and other circulatory disorders
how does the body compensate for respiratory acidosis?
kidneys retain bicarb to increase bicarb levels. Because this is an acidosis problem, kidneys will excrete H+ ions to help increase the pH
- this takes hours to days
what are causes for respiratory alkalosis (primary deficit of pCO2)?
- high altitudes decreased pCO2
- leads to hyperventilation - anxiety-induced hyperventilation
- hysteria - aspirin overdose
- pulmonary embolism/fibrosis
- O2 exchange is impaired
how does the body compensate for respiratory alkalosis?
kidneys decrease bicarb level by excreting it into the urine and reclaiming H+ to the blood (which will increase pH)
what are causes for metabolic acidosis (primary deficit of HCO3-)?
- acid addition:
- aspirin, ethanol, methanol, ethylene glycol
- diabetic keto acidosis / lactic acidosis (creation of acid) - base subtraction:
- renal failure (tubular necrosis)
- diarrhea (excessive tubular bicarbonate ion loss)
how does the body compensate for metabolic acidosis (primary deficit of HCO3-)?
Hyperventilation: the lungs will begin to excrete pCO2 in order to decrease the pH, and then eventually the kidneys will retain that missing bicarb and excrete H+ to decrease the pH
what are causes of metabolic alkalosis (primary accumulation of HCO3-)?
- increased acid subtraction
- loss of stomach acid via vomiting or nasogastric suction
- prolonged use of diuretics (increased acidic urine and alkaline blood) - increased base addition
- ingested NaHCO3- or antacid - potassium depletion (hypokalemia)
- Cushing’s, adrenal tumors, steroid therapy
how does the body compensate for metabolic alkalosis (primary accumulation of HCO3-)?
Hypoventilation: the lungs will begin to retain pCO2 in order to decrease pH
what is used to measure pO2 and pCO2 and pH?
pO2: amperometry
- reduction of oxygen produces a current that is proportional to the amount of oxygen present
pCO2 and pH: potentiometry
- electric potential between two electrodes (change in voltage indicates the [analyte])
what is the normal range for the following:
- pH
- pCO2
- pO2
- Bicarb (HCO3-)
- O2 saturation
pH: 7.35 - 7.45
pCO2: 35 - 44 mmHg
pO2: 80 - 100 mmHg
HCO3-: 23 - 29 mmol/L
Saturated O2: > 95%
What are the blood gas sample parameters?
- arterial draw
- mix tube asap to prevent clots
- run within 30 minutes of collection (if not, pH decreased and pCO2 will increase; also false K+ increase)
- can use ice but not for long
the liver functions to metabolize what four things? What other 3 functions does it do?
- metabolizes: carbs, lipids, proteins, and bilirubin
- detoxes harmful substances
- stores essential compounds
- cleans waste products into bile or blood for excretion
what two places does the liver receive blood? Where do supplies merge? And where does blood flow before leaving the liver?
liver receives blood in the
- hepatic artery
- portal vein: digestive tract to liver (main source)
supplies merge in the sinusoid (that is lined with hepatocytes that removes toxins)
blood flows to the central canal of each lobe before it leaves the liver
what are the two types of cells of the liver, and what are their functions?
hepatocytes: the major kind of liver cell that regenerate the liver
kupffer cells: macrophages that line the sinusoids and act as phagocytes (engulf bacteria, debris, toxins, ect)
Bilirubin is the ______ product of ____ cells. It’s basically ______ waste.
bilirubin: breakdown product of RBCs. Heme waste after hemoglobin is broken down