Acids 1. When HCl is dissolved with water or an aqueous solution, it dissociates producing what 2 components? 2. When carbonic acid dissolves with water, it yields what 2 components?

1. Hydrogen + Chloride ion 2. Hydrogen + Bicarbonate

Acids 1. When bicarbonates accept hydrogen, that yields what product? 2. When phosphorus accepts hydrogen from acid then it will produce what?

1. Carbonic acid 2. Phosphoric acid

Two Important Organs for Maintaining the pH of the Body 1. The one responsible for the respiratory control of CO2 2. For the reclaiming of bicarbonate from the glomerular filtrate

1. Lungs (respiratory mechanism and component) 2. Kidneys (renal mechanism and metabolic component)

(P) Lec 4: Acid-Base Balance (Part 1) Flashcards by Kchianna Lauren Coronel

A substance that can donate hydrogen ions when dissolved in water

Acid

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A substance that accepts a hydrogen ion but also donates a hydroxyl ion (OH-) when dissolved in water

Base

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The more hydrogen ions, the more ____ the solution is

Acidic (pH of < 7)

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Bicarbonate, phosphorous, and sodium hydroxide are bases that when dissolved in water, can yield ____ ions

Hydroxyl (OH-)

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Strong vs. Weak Acids and Bases

These completely dissociate when placed in an aqueous solution. They give off as many hydrogen ions that they can give.
These are partially broken down or dissociated and give off lesser hydrogen ions.

Strong
Weak

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Physiologically Important Acids

The 2 most commonly involved in acid-base balance are what?

Carbonic Acid (H2CO3)
Phosphoric Acid (H3PO4)

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A strong acid maintains a pKa of < ____ while a strong base has a pKb of > ____

pKa = < 3
pKb = > 9

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TOF: pKa and pKb stand for the dissociation constants of acids and bases

False (Ka and Kb are the dissociation constants)

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Dissociation Constants

These (2) formulae will be used to compute for the pH; an expanded Henderson Hasselbalch equation

pKa = -log(Ka)
pKb = -log(Kb)

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The negative logarithm of ionization that is constant for every acid. That constant is defined as the ability of the acid to dissociate in water; the pH wherein protonated and unprotonated components are equal in concentration.

Acid Dissociation Constant (Ka)

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Acids

When HCl is dissolved with water or an aqueous solution, it dissociates producing what 2 components?
When carbonic acid dissolves with water, it yields what 2 components?

Hydrogen + Chloride ion
Hydrogen + Bicarbonate

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Acids

When bicarbonates accept hydrogen, that yields what product?
When phosphorus accepts hydrogen from acid then it will produce what?

Carbonic acid
Phosphoric acid

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Maintaining Physiologic pH

Under normal conditions, acids and bases are constantly (added to/removed from) extracellular fluid compartments

Added to

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What are the 3 lines of defense in maintaining physiologic pH?

Buffer mechanism
Respiratory mechanism
Renal mechanism

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Two Important Organs for Maintaining the pH of the Body

The one responsible for the respiratory control of CO2
For the reclaiming of bicarbonate from the glomerular filtrate

Lungs (respiratory mechanism and component)
Kidneys (renal mechanism and metabolic component)

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These are solutions that resist changes in pH when acid or alkali is added, it is a mixture of a weak acid and salt of its conjugate base or weak base with its salt and a strong acid

Buffer

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A buffer is a mixture of:
1. Weak acid + ____
2. Weak base and it’s salt + ____

Salt of conjugate base
Strong acid

Note: Conjugate salts are with weak acids and bases

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This formula is for weak acids + conjugate bases and/or weak bases + strong acids

Henderson-Hasselback Equation

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Buffer systems of blood, tissue fluids and cells immediately (combine/dissociate) with acids or bases to prevent excessive changes in the concentration of hydrogen ions

Combine

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What is the principal buffer of PLASMA (ECF)?

Bicarbonate buffer (NaHCO3/H2CO3)

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What is the principal buffer of ERYTHROCYTES?

Hemoglobin buffer (KHb/HHb/KHbO2/HHbO2)

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What is the principal buffer of INTRACELLULAR FLUID?

Phosphate buffer (K2HPO4/KH2PO4)

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In the ECF, the bicarbonate buffer is considered as the principal buffer with the pKa of what?

6.1

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A phosphate buffer works best within what organ?

Kidneys (lobules)

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What are the 4 blood buffers?

1. Bicarbonate and Carbonic Acid 2. Inorganic Phosphorus 3. Hemoglobin 4. Plasma Proteins

# Blood Buffers - The most important ECF buffer in the body - One with the highest concentration - Is regulated by the kidneys and lungs

Bicarbonate and Carbonic Acid

# Blood Buffers This accounts for the 65% buffering capacity of plasma and the 40% buffering action of the whole body

Bicarbonate and Carbonic Acid

# Blood Buffers Is carbonic acid a weak or strong acid (H2CO3)?

Weak

# Blood Buffers The ratio of bicarbonate (HCO3) to carbonic acid (H2CO3) at a pH of 7.4 is what?

20:1 | Note: This is when the lungs and kidneys are functioning well

# The Mechanism of Action of Bicarbonate When a strong acid is added to the bicarbonate system: 1. What happens to the acid? 2. What happens to excess CO2?

1. A strong acid is replaced by a weak carbonic acid (so if there are changes in the pH, the effect will not be that big) 2. Excess CO2 is removed by respiration

# The Mechanism of Action of Bicarbonate This represents the reserve of alkali (bicarbonate) available for the neutralization of strong acids

Alkali Reserves

# The Mechanism of Action of Bicarbonate When a strong acid is added to the bicarbonate system: If a strong acid dissociates, it releases Hydrogen ions. Between the bicarbonate and carbonic acid, which one reacts to accept hydrogen?

Bicarbonate

# The Mechanism of Action of Bicarbonate When a strong acid is added to the bicarbonate system: Hydrogen and bicarbonate ions bind through the action of carbonic anhydrase to produce what?

Carbonic acid

# The Mechanism of Action of Bicarbonate When a strong acid is added to the bicarbonate system: Once carbonic acid is formed, it will be acted upon by carbonic anhydrase to release ____ and ____ molecules

CO2 and H2O | Note: CO2 will be expelled by the lungs

# The Mechanism of Action of Bicarbonate Where is carbonic anhydrase present in?

RBC Membranes

# The Mechanism of Action of Bicarbonate When a strong base is added to the bicarbonate system: 1. What happens to the concentration of carbonic acid (H2CO3)? 2. What happens to the CO2?

1. It decreases 2. CO2 combines with water to replace the H2CO3

# The Mechanism of Action of Bicarbonate When a strong base is added to the bicarbonate system: 1. Upon the drop in CO2 levels in the blood, what happens to the rate of respiration? 2. Upon the increase of bicarbonate (HCO3), what function will the kidneys perform?

1. Rate of respiration is inhibited 2. The kidneys will excrete the excess bicarbonate (HCO3)

# The Mechanism of Action of Bicarbonate When a strong base is added to the bicarbonate system: Hydroxyl ions given up by the strong acid will bind with carbonic acid to produce ____ with ____

Bicarbonate with water

# The Mechanism of Action of Bicarbonate When a strong base is added to the bicarbonate system: The excess HCO3 will just be present in the body and later on be released by what organ?

Kidneys

# The Mechanism of Action of Bicarbonate When a strong base is added to the bicarbonate system: A water molecule is acted upon by CO2 that is released by the tissue, upon being acted upon by carbonic anhydrase it produces what?

Carbonic Acid (H2CO3)

# The Mechanism of Action of Bicarbonate When a strong base is added to the bicarbonate system: The concentration of carbonic acid decreases, so more ____ combines with water to replace the carbonic acid

CO2

# The Mechanism of Action of Bicarbonate When a strong base is added to the bicarbonate system: To correct the sudden pH change, upon adding a strong ____ to water molecules, it will act on the CO2 producing carbonic acid

Base

# The Mechanism of Action of Bicarbonate If a strong acid is added, the bicarbonate reacts on it thereby (increasing/decreasing) CO2 as a net result

Increasing

# The Mechanism of Action of Bicarbonate How do you balance the pH when there is an increased CO2 level?

It will be excreted out the lungs through respiration

# The Mechanism of Action of Bicarbonate If a strong base is added, the carbonic acid reacts on it. More OH- is (added/released), and (more/less) bicarbonate is produced

1. Released 2. More

# The Mechanism of Action of Bicarbonate How do you balance the pH when there is an increased HCO3 (bicarbonate) level?

Bicarbonate will be excreted by the kidneys

# The Mechanism of Action of Bicarbonate TOF: Lungs are to CO2 while kidneys are to HCO3

True

This involves bicarbonates and carbonic acid as it expresses acid-base relationships and relates the pH of a solution to the dissociation properties of a weak acid

Henderson-Hasselbach Equation

TOF: The pH is equivalent to pKa when the concentration of acid is equal to the concentration of base

True

TOF: The value of pKa is lower for weak acids and higher for strong acids

False (lower; strong and higher; weak)

This is considered as the hydration and dissociation constant for CO2 in the blood as this pKa is constant at a level of ____

6.1

When the body needs oxygen, RBCs supply it to the organ in exchange for the tissue release of what?

CO2

After CO2 is released by the tissue, it binds with ____ or ____

Proteins or Water

When CO2 binds with water, it will be acted upon by ____ producing carbonic acid. This carbonic acid will be acted upon by the enzyme and will produce ____ together with ____.

1. Carbonic anhydrase 2. Hydrogen ions 3. Bicarbonate

TOF: The more that CO2 is produced, the more carbonic acid is being formed, therefore the more bicarbonate is being released

True

What will be the expanded HH formula when carbonic acid and bicarbonate values are not given?

- Total CO2 = HCO3 - H2CO3 - HCO3 = Total CO2 - H2CO3 - H2CO3 = (K)(partial CO2 level) | HCO3 is bicarbonate while H2CO3 is carbonic acid

In the expanded HH formula, this variable represents the solubility coefficient of CO2 in the plasma

K = 0.03

This is an end product of most aerobic metabolic processes in the body

CO2

When tissues release CO2, it can be dissolved where?

In the plasma

As water combines with the CO2 through the action of carbonic anhydrase (CA), it will form ____. When carbonic acid is being formed, it is also again acted upon by ____ producing hydrogen ions and bicarbonates

1. Carbonic acid 2. Carbonic anhydrase

When bicarbonate levels are increased, they are usually found where?

RBCs (once out of the RBC, they diffuse out to the plasma)

Upon the diffusion of bicarbonate to the plasma, this element then diffuses into the RBC, which increases negativity

Chloride

To maintain electroneutrality, on each side of the red cell membrane, chloride diffuses into the cell in exchange with bicarbonate that diffuses out of the cell. What is this process called?

Chloride Shift

# Blood Buffers - The intracellular fluid compartment (ICF) buffer - Consists of a 5% non-bicarbonate buffer of plasma and 16% non-bicarbonate value of erythrocytes - Plays a major role in buffering renal tubular fluid and intracellular fluids

Inorganic Phosphorus

Inorganic phosphorus has two different forms, what are those?

1. HPO4 - monohydrogen phosphate 2. H2PO4 - dihydrogen phosphate

The phosphorus buffer system is the most important in the titration and excretion of acids in urine. What form of phosphorus exists in the kidneys?

Monohydrate phosphate

The highest excretion of hydrogen ions happens in this organ because of the inorganic phosphorus buffer system

Kidneys (tubules)

The phosphorus buffer system is the most important in the titration and excretion of acids in urine. What form of phosphorus exists in the distal tubules?

Dihydrogen phosphate

Phosphorus concentration progressively (increases/decreases) as fluid is reabsorbed within the tubules. It buffers against changes in the tubular pH as it aids in (secretion/reabsorption) in the tubules

1. Increases 2. Secretion

TOF: When a strong acid releases hydrogen ions, to counteract and for it not to have an acidic pH, the dihydrogen phosphate reacts and produces monohydrogen phosphate

False (monohydrogen phosphate reacts to produce dihydrogen phosphate) | Note: Dihydrogen phosphate will be excreted in the urine

# Phosphorus Buffer System Another way of hydrogen ion release using a strong acid: As hydrogen ions are released by a strong acid, the abundant ammonia present in the kidneys or within the body will now become ____

Ammonium ions | Note: Ammonium ions will be excreted in the urine

# Which among them is the acidic and basic component? 1. HPO4 (monohydrogen phosphate) 2. H2PO4 (dihydrogen phosphate)

1. Basic 2. Acidic

When an acid is added to the phosphate buffer system, hydrogen ions are accepted by the base which is?

Monohydrogen phosphate (HPO4)

When a base is added to the phosphate buffer system, OH is buffered by the acid component which is?

Dihydrogen phosphate (H2PO4)

# Phosphorus Buffer System 1. (H+) + (HPO4) = ? 2. (OH) + (H2PO4) = ?

1. H2PO4 2. HPO4 + H2O

# Blood Buffers - A major intracellular buffer of RBCs - It is able to offload oxygen and combine with CO2 to diffuse across the cellular gradient - This alone is not effective, it works better in cooperation with the bicarbonate buffer system

Hemoglobin

# Hemoglobin It contains how many histidine residues?

# Hemoglobin This is a component of proteins or amino acids hence why it is a good buffer. The more residues of this, the more effective it is as a buffer

Histidine

# Hemoglobin 1. 1 gram of hemoglobin carries how many mL of oxygen? 2. How many percent of hemoglobin present in the body binds with oxygen?

1. 1.39mL 2. 95%

# Hemoglobin What happens to the excess hydrogen ions in this buffer system?

Uploaded to the environment

What are the 2 different sites for the Hemoglobin buffer system?

Tissues and Lungs

# 2 Sites of the Hemoglobin Buffer System (Tissue) 1. Every time the RBC goes into the tissue, the hemoglobin offloads its ____ there. 2. Before it can upload, ____ (aka hemoglobin bound with O2) is first converted, removing oxygen bound to the hemoglobin.

1. Oxygen 2. Oxyhemoglobin

# 2 Sites of the Hemoglobin Buffer System (Tissue) 1. Oxygen is now given off to tissue which in exchange for the oxygen given, it releases ____. 2. CO2 diffuses out of the tissue and now enters the ____.

1. CO2 2. RBC

# 2 Sites of the Hemoglobin Buffer System (Tissue) The CO2 that enters the RBC forms a complex with ____ through the action of ____ found inside the red cell membrane and forms now the carbonic acid

Water; carbonic anhydrase

# 2 Sites of the Hemoglobin Buffer System (Tissue) 1. Dissociation of carbonic acid causes the bicarbonate concentration to (increase/decrease) in the RBC. 2. As carbonic acid is being formed because of diffused CO2 combining with water, carbonic acid together with hemoglobin (oxyhemoglobin) this time with no oxygen at all now forms ____.

1. Increase 2. HHb + Bicarbonate | Note: HHb = Deoxyhemoglobin

# 2 Sites of the Hemoglobin Buffer System (Tissue) 1. As this bicarbonate is present and the more CO2 can enter the RBC, the bicarbonate level can (increase/decrease) inside the RBC. 2. As the bicarbonate level (increases/decreases), to maintain electroneutrality, ____ enters the cell

1. Increase 2. Increases; Chlorine

# 2 Sites of the Hemoglobin Buffer System (Tissue) When there is ____, if the tissue needs oxygen, RBCs will sense it. The oxygen will then dissociate to readily diffuse out of the RBC and into the tissue.

Oxyhemoglobin

# 2 Sites of the Hemoglobin Buffer System (Tissue) Chloride shifting happens when too much of ____ exists; it will diffuse out of the RBC forcing chloride to go in

Bicarbonate

# 2 Sites of the Hemoglobin Buffer System (Tissue) Bicarbonate has a ____ charge, that is why whenever there is an exchange of ions, electroneutrality must be maintained

Negative

# 2 Sites of the Hemoglobin Buffer System (Lungs) What type of oxygen is present in the lungs?

Inspired oxygen

# 2 Sites of the Hemoglobin Buffer System (Lungs) The inspired oxygen diffuses from the ____ of the lungs then goes into the blood complexing now with the hemoglobin forming oxyhemoglobin

Alveoli

# 2 Sites of the Hemoglobin Buffer System (Lungs) 1. The oxyhemoglobin can now combine with the ____ present inside the RBC forming carbonic acid and leaving behind its ____ molecule 2. As carbonic acid is being formed, this will be acted upon by carbonic anhydrase and it dissociates into ____ and ____

1. Bicarbonate; oxygenated 2. Water and CO2

# 2 Sites of the Hemoglobin Buffer System (Lungs) As carbonic acid is acted upon by carbonic anhydrase forming CO2 and water molecules, CO2 goes out of the RBC, diffuses into the lungs, and will be eliminated through ____.

Ventilation

# 2 Sites of the Hemoglobin Buffer System (Lungs) 1. The remaining bicarbonate in the RBC will be (increased/decreased) since it was used to form carbonic acid, and the bicarbonate in the plasma enters the RBC. 2. As bicarbonate enters the RBC, the ____ present goes out the cell

1. Decreased 2. Chloride

# 2 Sites of the Hemoglobin Buffer System (Lungs) 1. If the CO2 will not be expelled, it will cause (increased/decreased) hydrogen concentration. 2. If it is removed faster than usual, then it will result in (increased/decreased) hydrogen concentration.

1. Increased 2. Decreased

# 2 Sites of the Hemoglobin Buffer System (Lungs) What type of hemoglobin is present in the lungs whenever there is no oxygen bound to it?

Deoxyhemoglobin

# 2 Sites of the Hemoglobin Buffer System (Lungs) Deoxyhemoglobin + oxygen = ?

Oxyhemoglobin

# 2 Sites of the Hemoglobin Buffer System (Lungs) Oxyhemoglobin is a strong (acid/base), so a/an (acidic/basic) component will bind to it known as bicarbonate

1. Acid 2. Basic

# 2 Sites of the Hemoglobin Buffer System (Lungs) 1. A strong acid is now present within the RBC, bicarbonate reacts on it, and ____ is again formed together with ____. 2. As carbonic acid is formed, it will be acted upon by ____, producing water and CO2. 3. As CO2 is formed, it will go out of the RBC then to the lungs through ____. | Note: Bicarbonate is decreased as it was acted upon by oxyhemoglobin

1. Oxyhemoglobin; carbonic acid 2. Carbonic anhydrase 3. Respiration

# 2 Sites of the Hemoglobin Buffer System (Lungs) If CO2 cannot go out of RBC and is not expelled through respiration, then CO2 will accumulate within the RBC and the pH of body will be ____

Acidic