Acid and Base Balance and Imbalance

Page
2

Major intracellular buffer

H+ + HPO42- ↔ H2PO4-

OH- + H2PO4- ↔ H2O + H2PO42-

www.sliderbase.com

Slide 13

Protein Buffers

Includes hemoglobin, work in blood and ISF

Carboxyl group gives up H+

Amino Group accepts H+

Side chains that can buffer H+ are present on 27 amino acids.

www.sliderbase.com

Slide 14

2. Respiratory mechanisms

Exhalation of carbon dioxide

Powerful, but only works with volatile acids

Doesn’t affect fixed acids like lactic acid

CO2 + H20 ↔ H2CO3 ↔ H+ + HCO3-

Body pH can be adjusted by changing rate and depth of breathing

www.sliderbase.com

Slide 15

3. Kidney excretion

Can eliminate large amounts of acid

Can also excrete base

Can conserve and produce bicarb ions

Most effective regulator of pH

If kidneys fail, pH balance fails

www.sliderbase.com

Slide 16

Rates of correction

Buffers function almost instantaneously

Respiratory mechanisms take several minutes to hours

Renal mechanisms may take several hours to days

www.sliderbase.com

Slide 17

www.sliderbase.com

Slide 18

www.sliderbase.com

Slide 19

Acid-Base Imbalances

pH< 7.35 acidosis

pH > 7.45 alkalosis

The body response to acid-base imbalance is called compensation

May be complete if brought back within normal limits

Partial compensation if range is still outside norms.

www.sliderbase.com

Slide 20

Compensation

If underlying problem is metabolic, hyperventilation or hypoventilation can help : respiratory compensation.

If problem is respiratory, renal mechanisms can bring about metabolic compensation.

www.sliderbase.com

Slide 21

Acidosis

Principal effect of acidosis is depression of the CNS through ↓ in synaptic transmission.

Generalized weakness

Deranged CNS function the greatest threat

Severe acidosis causes

Disorientation

coma

death

www.sliderbase.com

Slide 22

Alkalosis

Alkalosis causes over excitability of the central and peripheral nervous systems.