Module 5: Acid-Base Balance Flashcards
Define an acid
Substances that release H+ when in solution
Define a base
Substances that bind with free H+ in solution
Define a strong acid
Substance that completely dissociates into H+ and is anion in solution
Define a weak acid
A substance that only partially dissociates into H+ and its anion in solution
What characterizes a strong/weak base
Its ability to bind H+
What is the difference in [H+] between solution A with a pH of 2.6 and solution B with a pH of 6.6?
10^4
or 10 000
What is the normal pH of arterial blood?
7.45
What is the normal pH of venous blood
7.35
At what blood pH does acidosis occur at?
Anything below 7.35
At what blood pH does alkalosis occur at?
Anything above 7.45
How does acidosis affect nerve and muscle cell function?
It suppresses the CNS
How dos alkalosis affect nerve and muscle cell function
It leads to over-excitability of both the CNS and PNS
Describe the effects acidosis or alkalosis could have on enzymes
It would either speed up or slow down enzymatic activities
Describe how acidotic blood will affect K+
More H+ than K+ will be secreted, leading to an increase in plasma K+, this will then lead to increased ability for excitable cells to become activated
What are 3 primary sources of H+
Carbonic Acid Formation
Inorganic acids produced from breakdown of nutrients
Organic acids from intermediary metabolism
Describe how carbonic acid is formed. What does it dissociate into?
CO2 and H2O byproducts from cellular respiration is converted into carbonic acid by carbonic anhydrase
It then dissociates into bicarbonate and H+
In tissues where CO2 is removed, which direction is the reaction directed towards
The backwards direction to produce less H+
How do vegetables counter the acidity of protein
Vegetables produce more basic compounds, which can help counter the H+ formed by protein metabolism of sulphuric acid and phosphoric acid
Give an example of an organic acid produced from intermediary metabolism
Lactic acid produced in the muscles
Fatty acids due to fat metabolism
What is a chemical buffer system
A mixture of two chemicals that interact in such a way to resist pH changes when something acidic/basic is added to the system
What are the four different buffer systems
The carbonic acid/bicarbonate buffer system
The protein buffer system
The haemoglobin buffer system
The phosphate buffer system
Describe what would happen if a base is added to a solution with the carbonic acid/bicarbonate buffer system
The base will bind with free H+, resulting in more carbonic acid produced
T/F
The phosphate buffer system is the most important in the body
False
The H2CO4/HCO3- is the most important in the body
What is the one limitation of the carbonic acid/bicarbonate system
It cannot buffer against changes in H2CO3 or HCO3-
Why is the carbonic acid/bicarbonate system highly affective (2)
1) Both carbonic acid and bicarbonate are present in high quantities in the ECF
2) Both carbonic acid and bicarbonate are high
What does the Henderson-Hasselbalch Equation do
Defines the relationship between H+ and a buffer system pair
What makes protein a good buffer system?
Because they are composed of amino acids, which that contain acidic and basic groups
Where is the protein buffer system most importantr?
For intracellular fluids, as they are very rich in protein
What is the haemoglobin buffer system most useful for?
H+ generated from metabolically produced CO2
Describe the phosphate buffer system
Uses an acid phosphate salt that can donate an H+ when the H+ concentration falls or accept an H+ when [H+] increases
What is the most important role for the phosphate buffer system?
Controlling the pH of the urine
How does the respiratory system play a role in buffering
By altering ventilation to increase or decrease the removal of CO2
T/F
Decreasing ventilation increases CO2
True
The decrease of exhalation of CO2 allows it to accumulate in the blood