ACID/BASE

Inadequate ventilation of the lungs

Respiratory acidosis Because the rate at which CO2 is eliminated from the body fluids through the lungs decreases. The result of this is increase the concentration of CO2 in the body fluids. As CO2 levels increase, excess CO2 reacts with H2O to form carbonic acid. The carbonic acid then dissociates to form hydrogen ions H+ and bicarbonate ions. The increase in H+ concentration causes the pH of body fluids to decrease. If the pH of body falls below 7.35 symptoms of respiratory acidosis become apparent.

Chemoreceptors?

Report to the medulla and pons both pressure and chemical makeup (pCO2).

Interference with respiratory muscles by disease, drugs, & trauma

Respiratory Acidosis

Hypoventilation due to depression of respiratory centers via narcotics, drugs and anesthetics?

Respiratory Acidosis (Elevated CO2)

Hypoventilation due to CNS disease and depression, trauma?

Respiratory Acidosis (elevated CO2)

Ascents to high altitudes

Respiratory Alkalosis

Bacteremias, Fevers

Respiratory Alkalosis

Malfunctions of either the respiratory system or kidneys can result in acidosis or alkalosis?

TRUE

Our lungs and kidneys are in charge of maintaining the acid base system?

TRUE

The kidneys will remove, reabsorb, or create bicarbonate?

TRUE

The medulla and pons alter your ventilation to maintain proper levels of pCO2?

TRUE

Blood gases are controlled by the respiratory system?

TRUE Every time we exhale, we blow off acid.

As blood pH deviates from 7.40 even with the presence of buffers, renal handing of bicarbonate and respiratory ventilation changes will kick in to attempt to restore pH?

TRUE It will try to compensate

An increase in hydrogen ion concentration will cause the pH value to be

REDUCED

Both the lungs and kidneys will help buffer the pH?

TRUE

what are the 3 major physiological buffer system in our body to maintain the ph of the blood:

1 proteins 2 Phosphate 3 Bicarbonate/Carbonic acid

How does the kidneys regulate the plasma levels of bicarbonate?

1. It can maintain plasma [HCO3-]- Freely filtered then reabsorb all of it. No bicarbonate in the urine and that plasma levels will stay the same. 2. It can lower the plasma [HCO3-]- Freely filter the bicarbonate and don't reabsorb any. The urine will have HCO3- and plasma levels will drop. Urine pH will become more basic and plasma will become more acidic. 3. It can raise the plasma [HCO3-]- freely filter then reabsorb all of it, but the DCT can make new molecules (so we generate more). Because it has carbonic anhydrase, it can synthesize bicarbonate, which is reabsorbed by the peritubular capillary, and the blood gets more basic and hydrogen ions get pumped into the tubule lumen as a result, the urine becomes more acidic.

Normal HCO3-

22-26 mEq/L

paCO2

35-45 torr

Carbon dioxide (CO2) a gas

= weak acid

Bicarbonate

= weak base

Any substance that accepts free hydrogen ions?

A Base; will make the solution less acid.

If we have carbon dioxide in the plasma, carbonic anhydrase will automatically transform it into __________

Carbonic acid

An enzyme that can speed up the reaction of making bicarbonate buffer?

Carbonic anhydrase

What are the 2 main regulators of pH in the body fluids?

Although buffers help resist changes in the pH of body fluids, the RESPIRATORY SYSTEM and the KIDNEYS are the main regulators of pH in the body fluids.

What are the general clinical signs of alkalosis and acidosis?

As for acidosis pH < 7.4 metabolic HCO3- decrease, respiratory CO2 increase For alkalosis pH > 7.4 metabolic HCO3- increase, respiratory CO2 decrease

How to calculate pH?

pH= pK + log (HCO3-/pCO2 9a) pH=6.1 +log 9HCO3-/CO2 X 0.03)

A weak acid and its conjugate based can be used together to make a _______: similarly, so can a weak base and its conjugated acid.

BUFFER

Why does our body chooses bicarbonate buffer system when its pKa is 6.1not ideal pH for our body?

Because we can control it physiologically, we have a better than predicted (chemically) buffer system. Our body acts as a chemist that can constantly change the dynamics of the solutions very advantageous for us.

Once carbonic acid is form, it spontaneously dissociates to _________ and ______

Bicarbonate ion and H+

Phosphate

Biggest extracellular source of phosphate is calcium phosphate from bone (calcium hydroxyapatite). Its pKa is 6.8, this system is particularly important in buffering acids within the renal tubules.

Acidosis is the result of either too much plasma acid ___ or too little base ___

CO2 HCO3-

Alkalosis is the result of either too much plasma base ______ or to little acid ______

CO2 HCO3-

Proteins

Can act as buffers b/c proteins are long chains of amino acids. Each amino acid has a variable R group we have neutral, acidic and basic R groups. Basic amino acids have an R group that can pick up a H+, to a certain degree, can act as a buffer.

The major effect of acidosis is depression of the _______

Central Nervous System (CNS) When the pH of the blood falls <7.35, the CNS malfunctions and the individual becomes disoriented and possibly enter a comatose state as the condition worsens.

They sense the levels of chemicals in the blood and cerebrospinal fluid (CSF) in the same place as the baroreceptors (aortic arch and carotid sinus)?

Chemoreceptors

The best buffering proteins have many________ in them because _________ have an optimal pH that is closest to that of blood?

Histidines

Albumin doesn't have many _______ but b/c we have so much of it, it still can act as a weak buffer?

Histidines The pKa of Histidine is 6.5

The major effect of alkalosis is _____________

Hyper excitability of the nervous system Peripheral nerves are affected first, resulting in spontaneous nervous stimulation of muscles. Spasms and titanic contractions and possibly nervousness or convulsions result. Severe alkalosis can cause death as a result of tetany of the respiratory muscles.

Occurs when the rate of removal of CO2 from the blood steam is higher than he rate at which the cells are dumping CO2 into the blood stream?

Hyperventilation Plasma CO2 levels decrease Blood becomes more basic and pH rises

Occurs when the rate removal is lower that the rate of production?

Hypoventilation Plasma levels of CO2 increase Blood becomes more acidic and pH drops

Where is carbonic anhydrase found?

Kidney tubules RBC membrane Epithelial cells of the stomach

Accumulation of lactic acid in severe hypoxemia

Metabolic Acidosis

Diarrhea (loss of intestinal HCO3-)

Metabolic Acidosis

Inadequate oxygen delivery to tissues resulting in anaerobic respiration and lactic acid build up

Metabolic Acidosis

Untreated diabetes mellitus

Metabolic Acidosis

Ingestion of Aspirin

Metabolic Acidosis (Lowered HCO3-)

Ingestion, infusion or production of fixed acids?

Metabolic Acidosis (Lowered HCO3-)

Decrease excretion of acid by kidney

Metabolic Alkalosis

Diuretic therapy (loss of H+ ions)

Metabolic Alkalosis

Intake of TUMS Antacids

Metabolic Alkalosis

Loss of gastric juice during vomiting

Metabolic Alkalosis

Excessive loss of fixed acids due to ingestion, infusion, or renal reabsorption of based?

Metabolic Alkalosis (Increase HCO3-)

Exercise, heart failure or shock

Metabolic acidosis

production of large amts. of fatty acids such as ketones

Metabolic acidosis

When the rate of CO2 production exactly matches what is blown off?

Normal ventilation

Restrictive, obstructive lung disease

Respiratory Acidosis

Severe emphysema or Advanced Asthma

Respiratory Acidosis

Overventilation on mechanical respirators

Respiratory Alkalosis

Hyperventilation syndrome (psychological)

Respiratory Alkalosis (lowered CO2)

Respiratory acidosis and respiratory alkalosis

Results from abnormalities of the respiratory system which in turn allow too much CO2 to be retained or much CO2 to be eliminated.

Metabolic acidosis and Metabolic alkalosis

Results from all other causes other than abnormal respiratory functions.

A weak acid will have only a small percentage of its molecule dissociated in aqueous solution the likelihood of the hydrogen ions re-associated is about equal the likelihood of dissociation?

TRUE

An acid is any substance that will release "free" hydrogen ions?

TRUE

As a deviation (blood pH) approaches setpoint 7.40, the compensation decreases, so the pH reaches set point?

TRUE

Hemoglobin has many histidines and works as a good buffer?

TRUE

If we hod our breath (or slow our breathing) we retain more acid?

TRUE

Too much of an acid/base change will end up denaturing the proteins (they will unravel)?

TRUE

Ventilation involves the rate and depth of inspiration and expiration?

TRUE

pKa refers to the "dissociation" constant for a particular walk acid or base?

TRUE

The buffer works best if its pHa is closely matched to the desired pH?

TRUE We pick the buffer whose pKa is closest to the pH we want.

All of our waste products will lower the pH?

TRUE, so our body needs buffers to maintain blood's pH constant.

The lungs can control the amount of carbonic acid in the body?

True, through the breathing rate.

HCO3- (Bicarbonate ) concentration is measured in ____

mEq/L

Measure of the hydrogen concentration of the solution?

pH -log[H+] where [H+] is usually expressed in moles/L

what is the pH of blood?

pH 7.40 and is maintained by homeostatic mechanisms

Bicarbonate/Carbonic acid

the pKa for the bicarbonate buffer system is 6.1

If a buffered solution suddenly has a lot of acid dumped into it_____

the weak base in the buffer could quickly bind the excess hydrogen ions and prevent drastic changes in the pH of the solution. A similar effect would be seen if s strong base were added: the weak acid in the solution would donate hydrogen ions and these would bind to the excessive hydroxyl radicals to form H2O.