acid-base balance

Question 1

what ion is vital to life? why?

Answer 1

hydrogen - number of ions in body fluid determines if body is in acidosis, alkolosis, or neutral

body fluid pH: 7.35 - 7.45

Question 2

how does it buffer

hemoglobin system

Answer 2

• maintains acid-base balance with chloride shift
• chloride shifts in + out of cells in response to O2 levels
• chloride ion into RBC = bicarbonate ion out of RBC

Question 3

how does it buffer?

plasma protein system

Answer 3

works with liver to vary amount of hydrogen ions in plasma protein structuce (plasma proteins can attract/release hydrogen ions)

Question 4

how does it buffer?

carbonic acid-bicarbonate system

primary buffer system

Answer 4

• carbonic acid concentration is controlled by lungs (rate + depth of resps change)
• bicarbonate concentration is controlled by kidneys (selectively retain/excrete bicarbonate)

~ lungs correct balance within 10 - 30 seconds
~ kidneys take a few hours to days to correct balance

Question 5

how does it buffer?

phosphate buffer system

Answer 5

neutralizes excess hydrogen ions (acts like bicarbonate)

Question 6

how it buffers

potassium

Answer 6

• in acidosis: hydrogen ions move into cells + force potassium out (creates hyperkalemia)
• in alkalosis: hydrogen moves out of cell + potassium moves in (creates hypokalemia)

Question 7

causes

respiratory acidosis

Answer 7

• asthma: spasms from allergens/irritants = smooth muscle constriction + ineffective gas exchange
• atelectasis: mucus plugs/infectious drainage = alveolar sac collapse + ineffective gas exchange
• brain trauma: excessive pressure on respiratory center or medulla oblongota = depressed resps
• bronchitis: airway obstruction
• CNS depressants (sedatives, opioids, anesthetics): CO2 retention
• emphysema + COPD: loss of elasticity in alveolar sacs restricts air flow out = increased CO2
• hypoventilation
• pneumonia: mucus/lung congestion obstruct airway
• pulmonary edema: fluid accumulation
• pulmonary emboli

PaCO2 will be high

Question 8

causes

respiratory alkalosis

Answer 8

• fever: increased metabolism overstimulates respiratory system
• hyperventilation blows off CO2
• hypoxia: stimulates respiratory center in brainstem = increases resp rate + decreases CO2 levels
• overventilation with mechanical ventialtors
• pain: overstimulation of resp center
• anxiety/hysteria

PaCO2 will be low

Question 9

causes

metabolic acidosis

Answer 9

• diabetes mellitus/diabetic ketoacidosis: insufficient insulin = fat metabolism + accumulation of ketones/other acids (depletes bicarbonate)
• excessive ASA ingestion: increases hydrogen ion concentration
• high-fat diet: fat metabolism waste products accumulate too fast (ketone/acid build up)
• insufficient carbohydrate metabolism: not enough oxygen for carb metabolism = lactic acid is production + lactic acidosis
• malnutrition: improper metabolism = fat catabolism, ketones + acids build up
• renal insufficiency/kidney disease: protein metabolism waste products are retained = increased acids
• severe diarrhea: intestine + pancreas secretions are alkaline = loss of bases

HCO3- will be low

Question 10

causes

metabolic alkalosis

Answer 10

• diuretics: loss of hydrogen ions/chloride = increased bicarbonate in blood
• vomiting or GI suctioning: hydrochloric acid loss
• hyperaldosternoism: too much sodium is reabsorbed = loss of hydrogen ions
• ingestion of sodium bicarbonate
• massive blood transfusion: citrate anticoagulant used to store blood is metabolized to bicarbonate

HCO3- will be high