Acid-Base Imbalances Flashcards
1
Q
measuring pH
A
measuring the concentration of hydrogen ions (H+)
2
Q
normal pH of extracellular fluid
A
- 35-7.45
- these numbers are ABSOLUTE (anything outside this range is abn)
- 7.4 = normal pH of blood
3
Q
compensatory mechanisms to keep blood within normal pH
A
- chemical buffers
- lungs (eliminate CO2 through ventilation)
- kidneys (excrete H+ and reabsorb and generate HCO3-)
4
Q
ABGs (arterial blood gases)
A
- tests blood from an artery for amounts of certain gases dissolved in arterial blood & measures pH
- interpreted to determine acid-base imbalances
5
Q
alkalosis
A
- inc base
- pH > 7.45
- low [H+]
6
Q
acidosis
A
- inc acid
- pH < 7.35
- high [H+]
7
Q
4 types of imbalances
A
- metabolic alkalosis
- metabolic acidosis
- respiratory alkalosis
- respiratory acidosis
8
Q
pH is dependent on balance b/w ___ and ___
A
- bicarbonate (HCO3-) and carbonic acid (H2CO3)
- homeostatic balance is a ratio of 20 bases: 1 acid
- acid base imbalances occur when this ratio is disturbed
9
Q
buffers (normal pH)
A
- carbonic acid/bicarbonate buffer used in blood
- chemicals in ICF and ECF provide immediate response - a weak base and its conjugate acid pair, or weak acid and is conjugate base pair
- pick up extra H+ if levels are high, release H+ if levels are low
10
Q
lungs (normal pH)
A
- CO2 exhaled by lungs, if lungs fail to exhale CO2 –> build up and inc in conc of carbonic acid = acidosis
- chemoreceptors in brainstem and peripheral chemoreceptors sense changes in PCO2 and alter ventilation rate to maintain acid-base imbalance
- prevents large pH changes from occurring while waiting for kidneys to respond
11
Q
kidneys (normal pH)
A
- excrete more or less H+ (acid)
- reabsorb more or less HCO3 (base)
- generate new HCO3 and release into blood
12
Q
CO2 + H2O H2CO3 H+ + HCO3-
A
- CO2 = acid component
- HCO3- = base componenet
- direction of rxn determined by conc of reactants and products
- Es speed up rxns
- Carbonic acid is volatile (dissociates as soon as it forms)
13
Q
respiratory imbalances: acidosis
A
- lungs failing, not adequately ventilating CO2, CO2 builds up
- causes: lung disease, depression of resp centers d/t drugs, nerve/muscle disorders reducing resp, holding one’s breath
- results in inc in pCO2
- excess CO2 combined with H2O to form carbonic acid
- responders: chemical buffers pick up excess H+ & kidneys excrete H+ and reabsorb more HCO3-
14
Q
respiratory imbalances: alkalosis
A
- hyperventilation, CO2 exhaled excessively, dec in PCO2, causing a dec in conc of carbonic acid and an inc in pH level
- causes: fever, anxiety, aspirin poisoning, high altitude
- responders: chemical buffers immediately drop off H+ ; dec [H+] and [CO2], removes stimulus for ventilation –> ventilation dec ; kidneys excrete less H+, reabsorb more HCO3-
15
Q
metabolic imbalances: acidosis
A
- too much acid or too little base
- causes: severe diarrhea (lose HCO3), diabetes mellitus, strenuous exercise, renal failure
- kidneys retain H+ instead of excreting it
- kidneys not reabsorbing/generating enough HCO3-
- responders: chemical buffers pick up extra H+ ; respirations inc ; kidneys secrete more H+, reabsorb more HCO3-
