Week 8- Acids/Bases Flashcards
Bicarbonate ion (HCO3-) is lost from
GI tract and in urine
Recovery of New Bicarbonate of Secretion of Ammonium
- metabolism of glutamine in renal tubule cells produces ammonium ions
- Glutamine = 2 NH4+ +. 2 HCO3-
- Ammonium ions are actively secreted via Na+/NH4+ counter-transporter
- NH4+ is then excreted and newly formed bicarbonate is reabsorbed
the respiratory system regulates acid-base homeostasis by
altering the rate and depth of ventilation
Elimination of CO2 is faster than it is produced
Respiratory Alkalosis
Common cause of respiratory alkalosis
hyperventilation, may occur with anxiety, fever, sepsis, or strenuous exercise
Decreased pH = increased H+
acidosis
Renal compensation involves invoking renal mechanisms discussed to ______
retain or eliminate bicarbonate as appropriate
Increasing ventilation will ______ CO2 from the body, thus reduce acid
remove
Decreasing ventilation will _____ CO2 that can form H+ and increase acid
retain
Increased pH = decreased H+
alkalosis
2 other examples of buffers
phosphate (effective in urine and intracellular fluid) Proteins such as hemoglobin
the renal system regulates acid- base homeostasis by
altering bicarbonate reabsorption, generating new bicarbonate, or by secreting bicarbonate
H+ lost in
vomitus or urine
Metabolic acid-base disturbances are all imbalances NOT caused by _______
too much or too little CO2 in the blood
acid and base homeostasis is largely regulated by
the respiratory and renal systems
- Bicbarb levels in the blood are above or below normal rang of 22-26 mEq/L
- Second most common acid-base imbalance
- Blood pH and HCO3- levels are below normal
Metabolic Acidosis
- Rising blood pH and HCO3-
- acid loss or bicarbonate ion retention are causes
- examples include vomiting (acid loss) and constipation (excess absorption of HCO3- by colon)
Metabolic Alkalosis
Important extracellular fluid buffer
Bicarbonate
Causes of Respiratory Acidosis
inadequate ventilation, pneumonia, cystic fibrosis, emphysema
Bicarbonate reabsorption depends on _______
H+ secretion
Molecules that release hydrogen ions (protons) in solution
Acids
Occurs by failure of respiratory system to function
Respiratory acidosis or alkalosis
Bicarbonate is reabsorbed using _______ in the renal tubule cells
carbonic anhydrase enzyme
Causes of metabolic acidosis
- excess alcohol ingestion (forms acetic acid)
- loss of bicarbonate (persistent diarrhea)
- diabetic ketoacidosis
Whats happening in respiratory acidosis
- CO2 accumulates in the blood
- Decreasing pH and increasing PCO2 are characteristic
Bicarbonate is freely filtered at the ______
glomerulus
Molecules that can accept a hydrogen ion
Bases
Most common type of acid-base imbalance
Respiratory acidosis
How is a new Bicarbonate Ion generated
- Recovery of new bicarbonate by secretion of H+ occurs when all filtered bicarbonate has been reabsorbed
- Secreted H+ combines with non-bicarbonate buffer (HPO4 2-)
- traps H+ in HPO4 2- ion for excretion
- Net gain of new bicarbonate ion occurs
