A&P - Acid/Base and Fluid-Electrolye Balance Flashcards
The regulation of acid/base balance refers to the control of what?
Regulation of H+ concentration in body fluid (homestatic mechanism)
Between pH 2, pH 6, and pH 10, which has the greatest concentration of H+ ions and which has greatest OH- ions?
pH 2 = greatest [H+]
pH 10 = greater [OH-]
What number on the pH scale represents neutral?
pH 7 ( meaning [H+] = [OH-] )
What are some of the most acidic substances in our bodies?
HCl - stomach acid (somewhere between pH 1 and 2)
What are the pH’s of the following?
1) arterial blood (and upper limit)
2) venous blood (and lower limit)
1) arterial blood - 7.4 (upper limit is 7.45)
2) venous blood - 7.37 (lower limit is 7.35)
At what pH level is blood maintained approximately
7.4
Define pH
Potential hydrogen - represents the negative logarithm of the molar concentration of H+ ions and indicates the degree of alkalinity/acidity of a solution
At what pH would be considered acidosis?
arterial blood pH < 7.35
At what pH would be considered alkalosis?
arterial blood pH > 7.45
Homeostasis of body pH depends largely on the concentration of H+ in the (extracellular/intracellular) fluid
extracellular
Name the 5 different ways in which H+ enters the bodily fluids
1) carbonic acid - glucose catabolism
2) lactic acid - excess lactate and H+ formed from anaerobic glucose catabolism
3) sulfuric acid - from oxidation of sulfur-containing amino acids
4) Phosphoric acid - from breakdown of phosphoproteins and ribonucleotides
5) Acid ketone bodies - formed during fat breakdown
Name the three acidic ketone bodies?
acetone, aetoacetic acid, B-hydroxybutyric acid
Which acid is formed as a result of glucose catabolism?
carbonic acid
Toxic accumulation of acidic ketone bodies is common in untreated what?
diabetes mellitus
Define: acid-forming minerals
minerals that remain after food has been metabolized and contribute to the formation of an acidic medium in the solution
Name three acid-forming elements
chlorine, phosphorus and sulfur
Acid forming elements are common in what type of diet?
Give 3 examples of foods in which you would find these elements.
Mixed diets
- high protein foods (meat, fish poultry, eggs)
- grains: wheat, corn, oats
- others: olive (oil), blueberries, rice, peanuts, red/black beans, butter, cheese, canola oil, sugar
Name two DIRECT acid-forming foods
Rhubarb (oxalic acid)
Cranberries (benzoic acid)
both foods contain acids that cannot be metabolized at all
Define: base-forming minerals
minerals that remain after food has been metabolized and contribute to formation of a basic medium in solution
Name four base-forming minerals
potassium, calcium, sodium, magnesium
Base forming elements are common in what type of diet? Give 3 examples of foods in which you would find these elements.
Strict vegetarian diet
- lots of fruits and veggies
- peppers, tofu, almonds, citrus fruits, grapes, blackberries, bananas, tomatoes, apples, green beans, lettuce broccoli, carrots, and avocado
- sea salt, garlic
- mineral H2O
Give an example of a DIRECT base-forming substance.
Antacids (sodium bicarbonate, calcium bicarbonate)
What are the two major types of control systems for acid-base balance?
Chemical and physiological
How fast do chemical buffers act?
fast as fk
Name the two physiological buffer systems?
Respiratory and Renal/Kidneys
How fast does the respiratory buffering system act?
Minutes
How fast does the renal response system act?
Hours (takes the longest)
Provide three examples of chemical buffer systems
Any of these:
1) bicarbonate (and carbonic acid)
2) phosphate
3) protein (plasma proteins)
4) Hemoglobin
Which is a very powerful physiological buffer system?
Renal (slower acting but more powerful than respiratory)
Acidosis is caused by what?
Too much H+ ion in the body fluids (or too little base)
Alkalosis is caused by what?
Too little H+ ions in the body fluids (or too much base)
What is a buffer?
A substance tha prevents a change in pH when an acid/base is added to it
What is typically the make-up of buffer pairs?
A weak acid and the salt of that acid
Buffers react with a relatively (strong/weak) acid or base to transform it into a relatively (strong/weak) acid or base, respectively.
strong; weak
True or False: A strong acid holds onto its H+ ions while a weak acid dissociates with its H+ ions quickly.
FALSE - strong acids/bases give that shit away, while weak acids hold on to their H+ ions (that’s why buffers make weak acids so there are less H+ floating around wreaking havoc)
When NaOH (sodium hydroxide) is added to the body, would carbonic acid or bicarbonate buffer the NaOH?
carbonic acid (the acid works on the bases aka NaOH) while bicarbonate works on the acids added
What is carbonic anhydrase?
enzyme that is involved in the formation of carbonic acid from CO2 and water
What is a chloride shift?
The process of exchanging a bicarbonate ion formed in RBC with a chloride ion from the plasma
(this happens as CO2 first comes into Hb and combines with H2O to create H2CO3 –> carbonic acid exchanges with potassium salt of Hb –> HCO3- that can leave RBC
True or False: Carbonic acid is buffered primarily inside RBC (red blood cell) which then produces HCO3- that diffuses down the concentration gradient into the blood plasma
True
How does vomiting cause metabolic alkalosis? What is the treatment?
Vomiting means you are puking up contents in your stomach include HCl, meaning that you are losing a lot of Cl- ions. As a result, this leads to an increase in bicarbonate in the ECF.
Tx: Normal saline (0.9% NaCl in water)
What is a volatile acid? Give an example.
Acids that evaporate via lungs (ex. carbonic acid) - buffered by potassium salts of hemoglobin and oxyhemoglobin
What is a non-volatile acid? Give an example.
aka a “fixed acid” and is produced in the body from sources other than CO2 and not excreted by lungs
Examples:
- HCl, lactic acid, ketone bodies (mainly buffered by sodium bicarbonate)
Carbonic acid results from the metabolism of what?
glucose catabolism
Put the following in the appropriate order from least basic (lower pH) to most basic (higher pH).
1) Oven cleaner
2) Baking soda
3) Great salt lake water
4) Household ammonia
Baking soda, great salt lake water, household ammonia, oven cleaner