M

co2 and metabolic acids - any acid except carbonic acid, ex. lactate, phosphoric, hydrochloric

what does normal cellular metabolism produce

h2c03

co2 and h20 combine to form what?

carbonic and metabolic acids

what must be excreted to maintain acid-base homeostasis

ph

what is the degree of acidity or alkalinity

40 nmolL, 40 x 10-9 mol/l

what is the measure of h+ ion concentration

7.40

what is the negative logarithm

hydrogen ion concentration

the alteration in ph is the change of what?

high ph

indicates few hydrogen ions

high ph

solution is alkaline

alkaline

what is basic

low ph

indicates many hydrogen ions

low ph

solution is acidic

7.35-7.45

what is the normal adult ph

buffers

control the ph of body fluids

respiratory system

adjusts amount of carbonic acid that remains in the body altering the rate and depth of respiration

35-45

what is the paco2 in arterial blood?

renal contribution

adjusts amount of metabolic acids that remain in the body by increasing acid excretion mechanisms to correct the problem

22-26

what is the hc03- concentration?

lungs

what compensates for acid base imbalances resulting from altered levels of metabolic acids

kidneys

what compensates for acid base imbalances resulting from altered levels of carbonic acids

paco2 and hco3

with compensation, ph returns to normal but what is abnormal?

buffers

weak acid plus its base that prevents large changes in ph by releasing or taking up H+

buffers

what are potential changes in ph adjusted immediately by?

body fluids

what do buffers contain?

bicarbonate buffer system

most important buffer in ECF

20:1

what is the normal ratio of bicarbonate to carbonic acid?

blood ph

what does any deviation from 20:1 alter?

lungs

excrete carbon dioxide and water \= carbonic acid

chemoreceptors

rate and depth of respiration normally are adjusted by what in response to acid-base and oxygen status

hyperventilation

decreases the amount of carbon dioxide in the blood and reduces the amount of carbonic acid

hyperventilation

will correct the imbalance of increased paco2 and decreased ph

hyperventilation

will compensate for the imbalance of decreased ph from excess metabolic acids

hypoventilation

allows carbon dioxdie to accumulate and increases the amount of carbonic acid in the blood

hypoventilation

will correct the imbalance of decreased paco2 and increased ph

hypoventilation

will compensate for imbalance of increased ph from deficit of metabolic acids

kidneys

excrete metabolic acids

kidneys

can secrete h+ into the renal tubular fluid and retain hco3- in the body or may allow some hco3- to be excreted, depending on homeostatic demands

buffered - titratable acidity

ammonium ions

explain h+ in the urine

metabolic acid in blood

what does the concentration of hco3- in plasma reflect the relative amount of?

decreased ph from excess of metabolic acids or carbonic acid to correct imbalance

explain what happens when there is more secretion of H+ into renal tubules and making more ammonia

increased ph from deficit of metabolic acids or carbonic acid to correct imbalance

explain what happens when there is less H+ secreted into renal tubules and making less ammonia

hydrogen ions secreted into the renal tubular lumen combine with filtered bicarbonate - which then is converted into co2 and reabsorbed - or buffers - phosphate - that remain in the tubular fluid - and ammonia and ammonium

explain the renal proximal tubule mechanism for excretion of metabolic acid

filtered hco3 is combined with secreted h+ to form carbonic acid, which dissociates into h20 and co2

co2 is lipid soluble and diffuses into the cells, where the reverse reaction converts it back to hco3- and h+

bicarbonate ion moves out of the basolateral membrane and returns to the bloodstream, whereas the h+ is returned to the lumen to bind with another hc03 ion

excess h+ ions are excreted into urine in combination with phosphate and ammonia bufferes

kidney is able to make new bicarbonate as needed to maintain ph balance

explain the bicarbonate ion reabsorption across the renal tubule

metabolic acidosis, respiratory acidosis, metabolic alkalosis, respiratory alkalosis

what are the 4 primary acid-base disorders?

acidosis

condition that tend to cause relative excess of acid

acidemia

if blood ph actually is decreased, what is present?

alkalosis

condition that tends to cause a relative excess of base (bicarbonate)

alkalemia

denotes an increased blood ph

metabolic acidosis

ph below 7.40 and abnormally low bicarbonate ion concentration

increase in metabolic acid - not carbonic, ex. lactic acid

decrease in hco3- ex. diarrhea

combination of the two

causes of metabolic acidosis

decrease

what does the mechanisms of metabolic acidosis do to the normal 20:1 ratio of hco3- to h2co3

headache, decreased bp, hyperkalemia, muscle twitching, warm, flushed skin (vasodilation), nausea, diarrhea, changes in loc (confusion, increased drowsiness), kussmaul respirations (compensatory hyperventilation)

what are s/s of metabolic acidosis?

decreased bicarbonate - primary imbalance

decreased paco2 - compensation

decreased/even normal ph, depending on degree of compensation

what does the compensatory response of metabolic acidosis do?

dka

severe diarrhea

renal failure

shock

what are causes of metabolic acidosis?

ketoacidosis - diabetes mellitus, starvation, alcoholism

severe hyperthyroidism

burns

circulatory shock

tissue anoxia - lactic acidosis

oliguric acute kidney injury or end stage chronic kidney disease

excessive intake of acids or acid precursors - ex. salicylates, methanol, ethylene glycol

what are interventions that have to do with increase in metabolic acid?

severe or prolonged diarrhea

gi fistula that drains intestinal or pancreatic secretions

intestinal decompression - drainage tubes

renal tubular acidosis

what are interventions that have to do with a decrease in base (bicarbonate)

respiratory acidosis

ph below 7.40 and abnormally high PaCo2

hypoventilation

what is respiratory acidosis?

impaired gas exchange - ex. lung diseases

inadequate neuromuscular function - ex. hypokalemic muscle paralysis

impairment of respiratory control in the brainstem - ex. opioid overdose

for respiratory acidosis, what are the causes of hypoventilation?

respiratory acidosis

decrease the normal 20:1 ratio of bicarbonate ion to carbonic acid by increasing the carbonic acid portion of the ratio

excretion of h+ and retention of hco3 by kidneys increases the hc03 concentration

increased paco2 \= primary imbalance

increased bicarbonate concentration \= compensation

decreased/even normal ph, depending on degree of compensation

explain the compensatory response of respiratory acidosis

hypoventilation -\> hypoxia

rapid, shallow respirations

decreased bp

skin/mucosa pale to cyanotic

headache

hyperkalemia

dysrhythmias - increased k

drowsiness, dizziness, disorientation

muscle weakness, hyperreflexia

what are interventions of respiratory acidosis?

respiratory depression - anesthesia, overdose, increase ICP

airway obstruction

decreased alveolar capillary diffusion - pneumonia, copd, ards, pe

what are causes of respiratory acidosis?