Wk 2 Acid/Base Flashcards
What is pH?
Power of hydrogen ions
0 is considered on pH scale
most acidic
14 is considered on pH scale
most alkalotic
What does [H+] indicate?
hydrogen ion concentration
When hydrogen ion concentration goes up, pH goes __
down
When [H+] goes down, pH goes __.
up
Examples of acidic materials
Soda, wine, mineral water
What are examples of bases?
Soap, laundry detergent
What is the most acidic substance in the human body?
hydrochloric acid
Acids have more H+ ions, so they can __ H+ ions
donate
Bases have less H+ ions so they can __ H+ ions
accept
Bases can give up what?
hydroxide ion OH-
__ acids dissociate completely in a solution.
strong
__ acids dissociate partially in a solution
weak
What does it mean when an acid completely dissociates in a solution?
It gives up all of its hydrogen ions
Hydrogen is a component of what 4 things in the diet?
Sugars
Proteins
Starches
Fats
List 4 functions of hydrogen in the body
- Helps maintain cell membranes
- Helps with enzyme activity
- Component of water and keeps the body hydrated
- Helps in energy production
What is a neutral pH?
7
A neutral pH is equal __ and __?
H+ and OH-
What is the typical pH of the human body?
7.35-7.45
Where is the pH measured in the body?
Blood serum, ABGs
Most acidic place in the body
stomach
What are 2 natural defense of the cells lining the stomach?
Cells secrete mucus and there is bicarbonate on the surface of the epithelial cells to keep it neutral pH
What protects the esophagus from the hydrochloric acid of the stomach?
lower esophageal sphincter (LES)
What part of the small intestine has defense mechanisms to neutralize the stomach acid?
duodenum
What is the pH of skeletal muscle?
6.9-7.2
What is the pH of bone?
7.4
What is the pH of the liver?
7.2
What is the pH of pleural fluid?
7.6
What electrolyte imbalances are caused by acid-base imbalance?
POTASSIUM, sodium, chloride
Most enzymes function in a __ pH range
narrow (7.35-7.45)
Acid-base imbalances can affect __
hormones
What curve reflects the effect of acid base imbalances on oxygen transport and delivery?
Oxyhemoglobin dissociation curve
If a person is acidic, this will have what affect on hemoglobin?
Hemoglobin will more readily give up oxygen at the tissues
If a person is basic, this will have what affect on hemoglobin?
Hemoglobin will more readily hold on to oxygen, so the tissues will struggle to oxygenate
Do we prefer a patient to be more acidic or more basic?
Acidic
What acidic pH is incompatible with life?
< 6.8
What basic pH is incompatible with life?
> 7.8
What are two types of acid in the body?
Volatile acids
Non-volatile acids
Volatile acids can be converted into __
gas
What type of acids can be converted into gas?
Volatile acids
Where are volatile acids excreted/eliminated?
Lungs
What is an example of a volatile acid?
Carbonic acid
What is the chemical symbol of carbonic acid?
H2CO3
What does carbonic acid break up into, so that it can be expelled by the lungs?
H20
CO2
Why can non-volatile acids not be converted to a gas?
They cannot be dissolved
What are 5 examples of non-volatile acids?
Lactic acid Phosphoric acid Sulfuric acid Acetoacetic acid Beta-hydroxybutyric
What organ system eliminates non-volatile acids?
Kidneys
What non-volatile acid is NOT eliminated by the kidneys?
Lactic acid
Where is lactic acid eliminated?
It’s metabolized by the liver and the kidney
What does phosphoric acid help with?
It works with calcium to help form our strong bones and helps to support kidney function
How is sulfuric acid created?
When proteins are metabolized by the body
Where is acetoacetic acid created?
In the liver
You will see an increase in beta-hydroxybutyric acid with
exercise, calorie restriction
Which acid is diagnostic of someone with diabetic ketoacidosis?
Beta-hydroxybutryic acid
What other acid can be measured for DKA, but is not the primary acid measured?
Lactic acid
What is something to note about lactic acid?
It can be converted if oxygen is re-established to the tissues and it will be utilized for energy production
The body produces more acids or bases?
Acids
What are three reasons that the body generates a lot of acids?
- the foods we eat
- metabolism of lipids and proteins
- cellular metabolism waste product
Cellular metabolism creates what waste product?
CO2 - a volatile acid
CO2 combines with H20 to make…
carbonic acid
What pH imbalance is more difficult to correct?
Metabolic alkalosis
3 ways the body maintains acid-base balance
Buffers
Respiratory system
Renal system
How do buffers work?
Immediately and all the time
The respiratory system works __ to fix acid-base imbalances but is..
rapidly, shorter lived
What system kicks in last and is responsible for long-term balance of acid/base?
Renal system
What are acid-base buffers?
Chemicals in the body that combine with an acid or base to change the pH
Buffers with either accept or release a __ __
hydrogen ion
The actions of buffers occur almost __ but is short lived
instantly
What are the 3 main buffer systems?
Bicarbonate – Carbonic acid buffer
Phosphate buffer
Protein buffer (including hemoglobin)
What type of buffer is bicarbonate?
carbonic acid buffer
Where is carbonic acid located?
extra cellular fluid
What is a byproduct of all the metabolism that occurs in the cells?
carbon dioxide (CO2)
CO2 combines with H20 to form __ __
carbonic acid
What breaks down carbonic acid?
carbonic anhydrase
Where is carbonic anhydrase located?
In many tissues, especially the lungs and kidneys
What happens if carbonic acid travels to the lung?
It is broken down by carbonic anhydrase into H2O and CO2 so the lungs can exhale the CO2
What happens if carbonic acid travels to the kidneys?
It breaks down into hydrogen and bicarbonate (HCO3-) to be excreted in the urine
When do we give patients sodium bicarbonate?
When they are acidotic and it isn’t being regulated through their respiratory system
What is HCO3-?
Bicarbonate
What is H2CO3?
Carbonic acid (water and carbon dioxide)
Bicarbonate is acidic or basic?
Basic
Someone who has overdosed on narcotics might have…
An increase in CO2 due to respiratory depression and be acidotic
What role do the kidneys have in the carbonic acid equation?
They get rid of hydrogen ions and generate bicarbonate (which is a base)
What role do the lungs have in the carbonic acid equation?
Expel CO2 which is an acid
H+ + HCO3- represents the role of the…
Kidneys
H2O + CO2 represents the role of the…
Lungs
What is the main intracellular buffer?
Phosphate buffer
What is the chemical equation of the phosphate buffer?
H+ + HPO4-2 = H2PO4-
How do you get a dihydrogen phosphate ion?
Hydrogen + hydrogen phosphate
How do we measure the acid/base buffer phosphate?
You can’t, all we know is that phosphate picks up a hydrogen ion to maintain intracellular pH
Nearly all proteins in the body can function as __
buffers
What is COOH?
Carboxyl group acids
What are carboxyl group acids?
Weak acids that give up H+
What are 2 examples of carboxyl group (COOH) acids?
Amino acid
Acetic acid
Amino group acids __ H+
accept
Amino acids have both a __ group and a __ group
Carboxyl and an amino group
What is the chemical equation for amino group acids?
NH2-
What are the two types of amino group acids?
Amino acids
Ammonia
Hemoglobin as a protein buffer can attach to __
CO2
How does hemoglobin serve as a protein buffer?
The more CO2 that is attached to the hemoglobin the less CO2 that is available to make carbonic acid
Cellular compensation is part of the __ system
buffer
Cells like to have a __ electrical charge
neutral
hydrogen ions are __ charged
positively
potassium ions are __ charged
positively
Major intracellular cation
potassium
If a patient is acidotic, hydrogen ions can move into the cell resulting in…
Potassium moving out of the cell because it is also positively charged leading to hyperkalemia
Hyperkalemia resulting from acidosis can be corrected by…
the kidneys if they are functioning properly
What is a problem with the kidneys excreting additional potassium resulting from acidosis?
There can be a potassium depletion because it was excreted by the kidneys during acidosis. Once acidosis is corrected there is no potassium to go back
Buffers make small changes that are…
not long lived
What is the chemical equation of carbonic acid?
H2CO3
What type of acids can’t be excreted by the lungs?
non-volatile acids (fixed) like lactic acid
Body pH can be adjusted by the lungs how?
Adjusting the rate and depth of respirations
The faster and deeper you breath the more…
CO2 you are blowing off
If a patient has a high hydrogen concentration (is acidotic) then the lungs might…
Increase in rate and depth to blow off additional CO2
If a patient is alkalotic, what will their respiratory rate and depth look like?
Both will decrease
Kidneys can secrete large amounts of acid except for what type of acid?
Carbonic acid
What method of acid/base balance is the long term regulator?
the kidneys
Do kidneys eliminate bases or acids?
They eliminate both
Kidneys can __ and __ bicarbonate ions
conserve and create
What method is the most effective regulator of pH?
the kidneys
If a patient with COPD is a CO2 retainer, what will the kidneys do?
Eventually they will compensate by holding on to bicarbonate
If kidneys are failing then…
pH is failing
Patients with renal failure often have to take __ daily to maintain normal pH
bicarbonate
Buffers work almost __
instantly
How long do respiratory mechanisms take to work?
Several minutes to hours
How long do renal mechanisms take to work?
Several hours to days
A pH of <7.35
acidosis
A pH of >7.45
alkalosis
What is the body’s response to acid/base imbalances called?
Compensations
Complete compensation is when…
pH brought back to normal limits
Partial compensation is when…
Range is still outside the norms
What do we measure when we get an arterial blood gas?
CO2 and bicarbonate levels
If the acid/base problem is metabolic, how will the body compensate?
Respiratory - hyperventilation or hypoventilation can help
If the acid/base problem is respiratory, how will the body compensate?
Renal mechanisms can bring about metabolic compensation
What receptors does the brain stimulate when there is an acid/base problem?
arterial receptors
What is the primary controller of H2CO3 (acid) supply?
Lungs
What triggers the lungs to increase or decrease the rate/depth of respirations?
In the lungs, excess CO2 combines with H2O to form carbonic acid
Hyperventilation __ pH
increases
Hypoventilation __ pH
decreases
What do kidneys do to bicarb?
Either excrete it or reabsorb it into the bloodstream
What is the primary controlled or HCO3 (base) supply?
Kidneys
Bicarbonate (HCO3) is a __
base
Carbon dioxide (CO2) is a __
acid
ABGs: Normal CO2 level
35-45
ABGs: Normal HCO3 level
22-26
