Patho: Acid-Base Balance

Question 1

What is the pH scale?

Answer 1

0-7 Acid (Acidic) 7-14 Base (Alkalotic)

Question 2

How can a change in Hydrogen or base concentration alter pH and acidity?

Answer 2

-Normal ECF pH is controlled to be between 7.35-7.45
-An Acid is a molecule that can release H+
-A Base is a molecule that can accept/combine H+
Release of H into the ECF increases acidity
Most found in the body are weak acids and bases.
Ex: Carbonic Acid and Bicarbonate

Question 3

Difference between Volatile and Non-Volatile.

Answer 3

1)Non-Volatile: Acids that are buffered by body proteins and bicarbonate and then are eliminated by the kidneys. Ex: Bicarnonate

2)Volatile: Acids that are excreted by the lungs.
Ex: Carbonic Acid (H2CO3) is volatile, and CO2 is excreted by the lungs.

Question 4

What are the metabolic sourced of body acids?

Answer 4

Inorganic Acids:
-Produced by protein metabolism (leads to ketosis)
-Sulphuric, hydrochloric, and phosphoric acids.
-Lactic acid (No O2 metabolite)
Results in more Non-Volatle acids (metabolic disorder)
Vegetarians have decr. acid production and have net production of base b/c of their diet.

Question 5

How is Carbon Dioxide transported in the bloodstream?

Answer 5

1) Dissolved in plasma (soluble in plasma) Ex:soda
2) Bound to Hemoglobin in the form of Carbaminohemoglobin
3) Bicarbonate in Plasma

Question 6

How does Carbon Dioxide attach itself to Bicarbonate in Plasma?

Answer 6

-CO2 combinbes with H20 = HCO3 in RBC’s.
-H+ is released to try and increase O2 release (tissues) and CO2 loading. (RBC-> Lung)
-H+ is buffered by hemoglobin, so causes little pH change.
-Once formed, HCO3 (bicarbonate) exits RBC’s and travels in the plasma towards the lungs.
-Once is reaches the lungs, it’ll renter RBC’s and combine with H+ = Carbonic Acid( H2CO3) which will spilt into H2O and CO2, and CO2 will be released by the respiratory system.
(Note: CO2 + H2O = HCO3 in RBC’s. Travels to lungs, reneters RBC’s and combines with H = H2CO3 = H2O + CO2. then CO2 is released by lungs.)

Question 7

Carbondioxide combined to Hemoglobin

Answer 7

Forms Carbaminohemoglobin:
-Causes changes in colour of blood.
-Dark red= deoxygenated.-Red= oxygenated.
It does not compete with O2It is influences by PCO2 (partial pressure) and amount of bound O2

Question 8

What mechanisms regulate pH in the ECF?

Answer 8

1) An Intracelluler and Extracellular buffering system

2) Respiratory controls3)Renal Controls.

Question 9

1) What is the Intracelluler and Extracellular Buffering system for pH regulation?
2) What are the Three General Buffering mechanisms to prevent large changes in pH?

Answer 9

1) -Consists of weak acids/bases that act as buffers and absorb small changes in pH.
- Buffers will bind with excess acids (H+) and prevent large changes in pH.(Will trade strong acid for weak acid, or a strong base for a weak base to prevent large changes in pH)

2) Three General Buffering mechanisms to prevent large changes in pH:
1) Proteins
2) Bicarbonate
3) Hydrogen
- Potassium Exchange.

Question 10

Protein Buffer

Answer 10

• The Largest buffer system in the body.
• Can buffer acids or bases.
• Mostly located witin cells.
• Albumin and plasma proteins act as buffers in the bloodstream.

Question 11

Bicarbonate Buffer

Answer 11

-Easy supply d/t the large presence of bicarbonate in the bloodstream (b/c of the CO2 transport) and breathing provides a nice outlet for excess CO2

Question 12

Hydrogen-Potassium Exchange

Answer 12

-Body cells transport excess H+ into the cells for exchange for K+ and vice versa for acid base balance.
Ex: When K lvls are low, K is reabsorbed in to the kidneys and Hydrogen is secreted into the urine, resulting in metabolic alkalosis in order to bring the K lvls back up again.

Question 13

Respiratory System for pH regulation.

Answer 13

• A rapid means of eliminating CO2-Cannot regulate pH alone as they cannot diectly get rid of H+
• Resp system is only getting rid of half the problem b/c it’s not getting rid of H+

Question 14

Renal System for pH regulation

Answer 14

• Reabsorbs bicarbonate and excreting H+ by the kidneys.
• Aids in returning pH to near-normal levels.
• This is the best mechanism for pH regulation.

Question 15

Differences between Metabolic and Respiratory Acid/Base Disorders

Answer 15

1) Metabolic:
- produces an alteration in bicarbonate concentration.
- Results from addition of non-volatile acids/bases to the ECF
- Procudes metabolic acidosis or metabolic alkalosis
- Incr. HCO3 and Incr. pH = Metabolic alkalosis
- Decr. HCO3 and Decr. pH+ Metabolic acidosis

2) Respiratory:
- Result from changes in respiratory rate increasing or decreasing and CO2
- Incr. PCO2 and Decr. pH = Respiratory Acidosis (d/t decr. RR)
- Decr. PCO2 and Incr. pH = Respiratory Alkalosis (d/t Incr. RR)

Question 16

Compare and Contrast Primary causes and Compensatory Mechanisms

Answer 16

Primary Cause:
Main reason for acidosis or alkalosis

Compensatory mechanisms:
Homeostatic mechanisms trying to prevent large changes in pH without treating the underlying cause.(Temporary measures)
-A compensatory state usually develops from homeostatic responses to the primary event.
A compensation means another system is trying to permit survival.
Resp cannot compensate for resp.
Resp can compensate for metabolic.
Ex: hyperventilation (resp) when there are too many ketones in the blood(metabolic)

Question 17

What is Metabolic Acidosis

Answer 17

Low pH (0-7 pH) caused by a decrease in bicarbonate. (Acidic)

Question 18

What is the Metabolic Acidosis compensation?

Answer 18

It compensates by increasing the respiratory rate in order to decrease PCO2 and H2CO3 (carbonic acid) levels.

Question 19

What are the causes of Metabolic Acidosis?

Answer 19

1) Increase in production of Non-Volatile metabolic acids.
2) Lactic Acid build up:
- incr. production or decreased clearance.
- produce by anaerobic metabolism in skeletal muscle (No O2)
- cleared by the liver and kidney. (so if there’s problems with those organs…)
- usually d/t inadequate O2 availability, such as in shock of cardiac arrest.
- Has also been reported in some cancers. 3)Ketoacids:
- produced by the liver from fatty acids and are used as fuel by many body cells.
- Overproduction occurs if there is insufficient CHO intake or inaccessible CHO.
- Common w/ uncontrolled DM, with fasting or starvation.
- Byproduct of protein breakdown to create glucose.
4) Decreased excretion of acid by kidney:
- Kidneys function to retain bicarbonate and excrete H+, in this case it doesn’t work and the acid isn’t removed.
- With kidney failure, wastes and metabolic acids are retained.
5) Excessive loss of bicarbonate ion:
- Caused by loss of body fluids (Diarrhea) or impaired reabsorption by the kidney.
6) Increase in chloride anion:
- Causes a proportional decline in bicarbonate ion.
- Can be caused by abnormal reabsorption in the kidney or use of chloride
- containing meds (Diuretics)

Question 20

S/s of Metabolic Acidosis

Answer 20

True S/s:

• weakness
• fatigue
• malasie
• dull headache
• possible digestive problems.

Compensatory:
-Incr. RR (to reduce PCO2) to decr. blood pH
This is shown by rapid deep breaths “Kussmaul Breathing”.
As pH drops, it can cause dangerous cardiac complications (cardiac contractility can decr. and CO can decr.
Arrhytmias and ventricular fibrillation can occur.

Question 21

Tx of Metabolic Acidosis

Answer 21

• Focused on correcting the underlying condition
• Restoring fluids and electrolytes that have been lost.
• Improving O2 b/c of lactic acidosis
• Supplemental sodium bicarbonate b/c the loss of bicarbonate incr. acidosis.

Question 22

What is Metabolic Alkalosis?

Answer 22

High pH ( 7-14 pH) due to excess bicarbonate ions.

Question 23

What are the causes of Metabolic Alkalosis?

Answer 23

1) Excess alkali intake:
- Alkali intake from bicarbonate containing antacids/meds.

2) Bicarbonate retention:
- Can be triggered by hypokalemia.
- Repeated vomiting results in alkalosis b/c it “drains” the body of Cl- and replaces it with bicarbonate ion. (dehydration)

3) Maintenance of Metabolic Alkalosis:
- Decr. in ECF fluid volume increases fluid rentention from the kidneys (to hold onto fluid), leading to an increased bicarbonate b/c it’s not being excreted.

Question 24

S/s of Metabolic Alkalosis

Answer 24

True S/s:

• Can be asymptomatic or s/s of hypovolemia.
• Severe: mental confusion, hyperactive reflexes, tetany, carpopedal spam.

Compensatory:

• Hypoventilation
• hypoxia
• respiratory acidosis.

Question 25

Tx of Metabolic Alkalosis

Answer 25

• Focused on correcting the underlying condition.
• Treating chloride defici (to incr. bicarbonate/HCO3) with potassium chloride (when there is a potassium deficit as well.) b/c low Cl = high HCO3
• Fluid replacement with normal saline (from dehydration)

Question 26

What is Respiratory Acidosis?

Answer 26

An increase in PCO2 and H2CO3 along with a decr. in pH
Associated with acute respiratory failure. (Not removing CO2)
Accompanied by renal compensatory mechanisms that conserve and generate bicarbonate.

Question 27

Etiology of Respiratory Acidosis

Answer 27

Occurs with impaired alveolar ventilation.

-Acute or Chronic conditions Ex: COPDBlood pH will drop quickly as renal compensatory mechanisms take time to kick in.

Question 28

Respiratory Acidosis Ventilation disorders

Answer 28

Acute:

• Impaired signalling from the medulla
• lung disease,
• chest injury,
• weakness of resp muscles or airway obstruction
• can result if breathing high CO2 content.

Chronic:

• Chronic bronchitis and emphysema
• Stimulates renal H+ secretion and reabsorption of bicarbonate.

Question 29

Why is there increased CO2 production with Respiratory Acidosis?

Answer 29

1) can result from fever, exercise, sepsis, and burns.
2) CHO rich diet will increase production of CO2 b/c CHO’s eventually breakdown into CO2CO2 production is usually matched by increased respiration, provided that the person is healthy.

Question 30

S/s of Respiratory Acidosis

Answer 30

Elevated lvls of CO2 can produce:
-vasodilation of cerebral blood vessels causing headache, blurred vision, irritability, muscle twitching, psychological disturbances.

As severity increases, there is : paralysis, impaired consciousness and incr. CSF pressure.

Question 31

Tx if Respiratory Acidosis

Answer 31

Improve ventilation.

Question 32

What is Respiratory Alkalosis?

Answer 32

Decreased PCO2 with an increae in pH

Question 33

What are the causes of Respiratory Alkalosis?

Answer 33

1)Hyperventilation or incr. RR than needed to maintain PCO2 lvls.
2)Incr. RR signals from medulla.
3)Stimulation of medullary cener occurs with pregnancy, anxiety, pain, sepsis, and ecephalitis (inflammation of the brain from viral infection) 4)Hypoexmia can also lead to increased respiratory rate, even with no nead to incr. ventilation for PCO2.
By breathing fast and a lot, the body is getting rid of too much CO2.

Question 34

S/s of Respiratory Alkalosis

Answer 34

Increased neuromuscular excitability, constriction of cerebral blood vessels, light
-headed, dizzy, tingling, numbness of fingers and toes, sweating, palpitations, panic, air hunger, dyspnea.

Question 35

Tx of Respiratory Alkalosis

Answer 35

By breathing fast and a lot, the body is getting rid of too much CO2.

Tx: Increase PCO2 by rebreathing into a paper bag and slowing RR, b/c you’re rebuilding the CO2 you’ve lost.

Question 36

Causes of Respiratory Acidosis

Answer 36

Slow shallow respirations. Not excreting CO2 making the blood Acidic

Question 37

Causes of Respiratory Alkalosis

Answer 37

Hyperventilation.

Excreting too much CO2 decreasing PCO2 and increasing pH making the blood Alkalotic