What is Normal blood pH
7.37 to 7.44
pH rises above 7.44
pH drops below 7.37
This is the major metabolic source of acid in the body
CO2, produces H2CO3 (carbonic acid)=CO2 + H2O
What are other sources of metabolic acid in the body
Catabolism of phosphorous containing compounds- Releases phosphoric acid into ECF
Glycolysis produces lactic acid
Fatty acid oxidation produces ketone bodies
A buffer is
a solution that resists change in pH in response to added acid or base
Buffers consist of
weak acid(HA) and its conjugate base(A-)
These are used as the major source of metabolic energy during fasting
(Ketone bodies)they are produced from Fatty Acid breakdown.
What are the major buffer systems in the body?
Bicarbonate-carbonic acid - ECF
Hemoglobin buffer system - RBC
Phosphate buffer system - all cell types
Ammonium and phosphate ions - kidney
Majority of CO2 is produced in
the TCA cycle(AKA: Krebs or Citric Acid Cycle)
(~13 moles or 0.5-1 kg per day)
CO2 + H2O = H2CO3 = H+ + HCO3-
Respiration Rate Controls
If pH rises what happens to respiratory rate
the individual breathes more shallowly (expires less CO2)
What condition occurs when elevated levels of Ketone bodies are produced
What is the body's response to an increase in [H+]
Stimulates respiratory center to INCREASE respiratory rate & DECREASE arterial (CO2) Equation:
(HCO3- + H+ → H2CO3 → CO2 + H2O)
The respiratory center in the brain acts within minutes to remove what through expiration
How long does it take the Renal system to affect pH
requires hours to days to affect pH
What is the range of Intracellular pH
7.1 - 7.4
The Liver, Heart and Nervous system function at what pH range
pH 6.8 - 7.8
We produce ~ how many moles of acid per day
What causes Metabolic Acidosis
Primary disorder is that there is an increased production of H+ by tissues, so blood [H+] is increased, so pH of blood is decreased.
What is the body's compensatory response to Metabolic Acidosis
H+ are buffered by HCO3-, producing H2CO3, Compensatory Response is Hyperventilation occurs, expiring CO2.
What causes Respiratory Alkalosis
Primary disorder: excessive expiration of CO2 by hyperventilation thereby decreasing blood CO2. Blood pH increases and [H+] is decreased.
What causes Respiratory Acidosis
Primary disorder: insufficient expiration of CO2 from lungs, thereby increases blood CO2, increases [H+], and decreases pH.
What causes Metabolic Alkalosis
Primary disorder: prolonged vomiting causes excessive loss of H+ and volume depletion, thereby decreasing blood [H+] and increasing pH. Compensatory response is HYPOventilation, thereby increasing blood CO2.
What are the major buffers of ICF (Intracellular Fluid)
Phosphate anions and proteins
Transport of hydrogen ions out of the cell is important in maintaining
If cell becomes too acidic (more H+ is transported out) in exchange for whtat
If cell becomes too alkaline (more bicarbonate is transported out) in exchange for what
How are Nonvolatile acids excreted
Nonvolatile acids include
Phosphate and Ammonium ions, Uric acid, Dicarboxylic and Tricarboxylic acids.
Most nonvolatile acids buffer the urinary pH between
5.5 and 7.0
(5.0 is a minimum urinary pH)
What is the major contributor to buffering urinary pH (but not blood pH)
Ammonium (NH4+): Ammonia (NH3), is a base, combines with proton producing ammonium ions (NH4+)
(NH3 + H+ ↔ NH4+)
From what is Ammonia produced
from AA metabolism or absorbed through intestine.
HCl or gastric acid is secreted by what
parietal stomach cells
(Strong acidity denatures ingested proteins and facilitates their digestion)
What substance is secreted from Pancreatic cells and the intestinal lining to neutralize
the stomach contents that are released into the lumen of small intestine
If pH falls what happens to respiratory rate,
the individual breathes more rapidly (expires more CO2)