Acid Base Balances

How should you think about the relationship between pH and [H+]

Think of an inverse ratio or proportion.

What happens to pH when [H+] goes up?

The pH goes down.

What happens to pH when [H+] goes down?

The pH goes up.

What does a higher [H+] mean?

The lower the pH and the more acidic.

What does a lower [H+] mean?

The higher the pH and the more alkaline.

Do different substances have different pH levels?

Yes. Different substances have different pH levels.

What do acids have?

More H+ ions.

What can acids do?

Acids are substances that can donate a H+.

What do bases have?

Bases, or alkaline substances, have less H+ ions.

What can bases do?

Bases accept H+ ions and give up hydroxyl ions (OH-).

What is the most acidic place in the body?

The stomach.

Why can the stomach handle HCl?

The stomach is uniquely designed to handle HCl.

What happens if HCl is found outside the stomach?

HCl found outside the stomach causes damage.

What does the duodenum do with stomach acid?

The duodenum has defense mechanisms to neutralize the acid.

What does the LES prevent?

The LES prevents the movement of gastric acid into the esophagus.

Are pH ranges the same throughout the body?

No. There are different pH ranges throughout the body.

What should you know about pH in the GI tract?

There are many differences in the GI tract.

Why are different pH ranges in the GI tract important?

This aids in digestion.

What is the pH range of skeletal muscle?

6.9-7.2.

What is the pH of bone?

What is the pH of the liver?

What is the pH of pleural fluid?

7.4

7.2

7.6

Why is hydrogen important in the body?

Hydrogen helps maintain cell membranes, helps with enzyme activity, is a component of H2O and keeps the body hydrated, and helps in energy production.

What substances contain hydrogen?

Sugars, proteins, starch, and fats.

: What does a pH of 7 mean?

There are equal [H+] and [OH-].

What normal serum pH range does the body maintain?

7.35-7.45.

What would be considered neutral in the body's serum pH range?

7.40 would be neutral.

Where is acid-base pH measured?

In the serum (blood).

Which electrolytes can acid-base balance affect?

Sodium, Potassium, Chloride

What else can acid-base balance affect besides electrolytes?

Hormones.

How does acid-base balance affect oxygen?

Oxygen transport and delivery are also affected.

What curve is affected by acid-base balance?

The oxyhemoglobin dissociation curve.

Can the body function outside the normal pH range?

The body can function for a short time outside that range.

What pH is incompatible with life

pH < 6.8 or > 7.8 is incompatible

What are some things that can change pH?

Ingesting food/drink, metabolism of lipids and proteins, and cellular metabolism waste products such as CO2.

Does the body produce more acids or bases?

The body produces more acids than bases.

What is CO2 considered?

CO2 is a volatile acid and is a cellular metabolism waste product.

Why is it important to restore pH?

It is important to get the pH back into a survivable range.

What pH range identify as a survivable range to restore toward?

7.2-7.5/6

Why do you want to avoid alkalosis, especially if the person is ill?

The hemoglobin holds on to oxygen more.

What is more difficult to correct

An alkaline pH.

What are the 2 types of acids in the body?

Volatile acids and non-volatile acids.

What are volatile acids?

Acids that can be converted to gas.

How are volatile acids eliminated?

They are excreted/eliminated by the lungs.

What is the one volatile acid in the body?

Carbonic acid: H2CO3.

What is the carbonic acid equation shown?

H2CO3 → H2O + CO2.

What are non-volatile acids?

Lactic acid, phosphoric acid, sulfuric acid, acetoacetic acid, and beta-hydroxybutyric acid.

How are non-volatile acids generally eliminated?

They are eliminated by the kidney.

What is the exception to kidney elimination of non-volatile acids?

Lactic acid.

How is lactic acid metabolized?

Lactic acid is metabolized by the body, primarily by the liver and kidney.

What are the components of acid-base homeostasis?

Buffers, respiratory system, and renal system.

What are buffers?

Chemicals in the body that combine with acid or base to change the pH.

What can buffers do with H+?

Buffers can accept or release a H+.

How quickly do buffers work?

Almost instantaneously.

How long does the action of buffers last?

Buffers are short-lived.

What are the 3 main buffer systems?

Bicarbonate-carbonic acid buffer, phosphate buffer, and protein buffers.

What protein is included in the protein buffer group?

Hemoglobin

Where is the bicarbonate-carbonic acid buffer located?

ECF (extracellular fluid).

What is the main ECF buffer?

The bicarbonate-carbonic acid buffer.

What produces CO2?

CO2 is a byproduct of cellular metabolism.

What happens to CO2 in the serum?

CO2 combines with H2O in the serum to form carbonic acid.

What enzyme breaks down carbonic acid?

Carbonic anhydrase.

Where is carbonic anhydrase found?

Carbonic anhydrase is found in many tissues of the body, especially the lungs and kidneys.

What occurs in the lungs involving carbonic acid?

H2O + CO2.

What occurs in the kidneys involving the bicarbonate buffer?

H+ + HCO3-.

Which is more powerful in changing blood pH, HCO3- or H2CO3?

H2CO3 is 20 times more powerful in changing the pH of the blood.

What happens for every H2CO3 loss in the blood?

For every H2CO3 loss in the blood, 20 HCO3- ions must be eliminated.

Why is a reservoir of HCO3- important?

The body makes more acids than bases, so a "reservoir" of HCO3- is important to rapidly neutralize any acid that is made and keep the pH within the normal range.

What is the main intracellular buffer?

The phosphate buffer.

Can proteins function as buffers?

Nearly all proteins can function as buffers.

What does the carboxyl group (COOH) do?

The carboxyl group (COOH) is a weak acid that gives up H+.

What group accepts H+?

The amino group (NH2-) accepts H+.

What two groups do amino acids have?

Amino acids have both a carboxyl group and an amino group.

What substances are listed with protein buffering?

Amino acid, acetic acid, and ammonia (NH3).

What does hemoglobin "pick" up at the cellular level?

CO2 at the cellular level.

What ions are involved in cellular compensation?

H+ and K+.

Where is the highest concentration of K+?

Inside the cell.

What happens when [H+] increases?

The pH decreases and becomes more acidic.

What happens to H+ during cellular compensation?

H+ moves into the cell.

What happens when more H+ moves into the cell?

There are more positively charged ions in the cell.

What happens to K+ when H+ moves into the cell?

K+ moves out of the cell.

Why does K+ move out of the cell?

Electrical neutrality is restored inside the cell.

Is cellular compensation a permanent correction?

No. It is a temporary correction of the pH.

What happens during acidosis regarding [H+]?

Acidosis is associated with increased [H+].

What do cells do with H+ during acidosis?

Cells pull H+ into the cell.

What happens when there are too many positive ions inside the cell?

Cells push K+ out

What do CO2 and H2O create?

Carbonic acid.

How can body pH be adjusted through respiration?

By changing the rate and/or depth of respiration.

What does exhaling CO2 do to H2CO3?

Decreases H2CO3.

What is correction of carbonic acid dependent on?

It is dependent on components of the respiratory system.

What components of the respiratory system are involved in correcting carbonic acid?

Chemoreceptors

Respiratory neurons

Motor neurons

Diaphragm

Respiratory muscles

Chest wall and airway structures.

What can the kidneys eliminate?

The kidneys can eliminate large amounts of acid except carbonic acid.

Can the kidneys excrete base?

Yes. The kidneys can excrete base (bicarbonate).

What can the kidneys do with bicarbonate ions?

The kidneys can conserve and produce bicarbonate ions.

What is the most effective regulator of pH?

The kidneys.

What happens if the kidneys fail?

pH balance fails.

What does kidney regulation of pH depend on?

Normal function of the renal system.

How quickly does the respiratory system correct acid-base changes?

Several minutes to hours.

How quickly does the renal system correct acid-base changes?

Hours to days.

What is acidosis according to pH?

pH < 7.35

What is alkalosis according to pH?

pH > 7.45

What is partial compensation?

pH remains outside the normal range.