Acid Base Balance
Card Set Information
Acid Base Balance
a charged molecule (ion), can conduct electricity
pH is defined as:
-log [H+] (hydrogen ion concentration)
H+ (hydrogen ions) are responsible for:
increased production of H+ causes a ....
decreased pH (more acidic)
pH of 7.0 :
pH of < 7.0:
pH of > 7.0:
neutral (pure water)
strong acids ionize almost completely in ....
weak acids exist in equilibrium between the .... & .... states
ionized & unionized
<--> indicates :
reaction is reversible & direction depends on the concentration
measurement of how much of an acid dissociates under normal conditions
equilibrium constant (KA)
strong acids have a .... KA, weak acids have a .... KA
large , small
changes in H+ alter ....
cell protein & enzyme shape & function
H+ formed in the body can arise from production of either .... or .... acids
fixed or volatile
referred to as metabolic acids
is referred to as respiratory acid (CO2)
the excess H+ ions must be .... & ....
neutralized & eliminated
substance that can neutralize acids or bases with only minor changes in pH
once equilibrium is reached, ....
buffer solutions neutralize strong acids by ...
converting them into a weak acid & a salt of the strong acid
at rest, metabolism consumes .... of 02 per minute .
And produces .... of CO2 per minute.
C02 produced must be eliminated to prevent the ....
build up of acids in the blood
normally CO2 is eliminated by .... as soon as it's produced
CO2 is transported in the blood by .... & ....
plasma & RBC
accounts for 5% of total transport & is the measure PCO2
dissolved in plasma
normal PCO2 in arterial blood is ....
normal PCO2 in venous blood is ....
accounts for 1% of total transport, forms carbamino compounds
combined with plasma proteins
slow rate, forms carbonic acid that dissociates to H+ ions & HCO3
gaseous form of CO2 is in equilibrium with the ....
aqueous form (H2CO3)
a volatile acid is in equilibrium with the ....
is the only physiologically significant volatile acid
majority of C02 (89%) is carried in the ....
RBC's by 3 mechanisms
5% is dissolved in the ....
21% combines with .... to form ....
Hb to form carbamino Hb
63% is carried as .... produced by a reaction
the buffering effect of Hb has .... effects
1. the .... reaction continues & speeds up as product is removed
2. it prevents .... from occurring
3. Bicarb ions accumulate & diffuse ....
out of the RBC
negative charges lost from the cell by diffusion of bicarb ions out are replaced by diffusion of Cl- into the the cell to maintain electrical neutrality
hamburger effect or chloride shift
the majority of C02 transported to the lungs is in the form of ....
at the lungs, the pressure gradients are reversed & hydration reaction is driven the other way, ....
Hb02 carries less C02 than ....
increase in affinity for C02 in deoxygenated blood (reduced Hb) & decrease affinity in oxygenated blood (02 Hb)
02 is carried bound to the ....
Fe+2 in heme
C02 is carried bound to amino groups on the .... & .... chains
alpha & beta
the .... & .... effects are mutually enhancing
Bohr & Haldane
at the tissues, the release of 02 is enhanced by .... & ....
02 decrease & C02 increase
C02 & H+ .... Hb's affinity for 02
at the lungs, it is enhanced by .... & ....
increased 02 & decreased C02
Name the 3 ways the blood pH is maintained
1. blood buffer system
2.elimination of C02 by ventilation
3. elimination of hydrogen ions & reabsorption of bicarb by the kidneys
the buffer system resists changes in .... when an acid or base is added
blood buffers are concerned with neutralizing H+ ions (acids) produced by ....
most alkaline conditions are caused by ....
decreases in H+
an open buffer system, for buffering fixed acids
a closed buffer system, for buffering fixed or volatile acids
the bicarbonate buffer system consists of .... & ....
HC03- & the acid H2C03 (carbonic acid)
the end product of buffering reaction (C02) is continuously removed by ventilation, preventing the reaction from reaching equilibrium
open buffer system
bicarbonate buffer buffers .... only, not volatile acids
as long as ventilation continues the reaction is driven to the .... & buffering action continues
H+ is not actually removed, it is ....
converted to H20
C02 is ....
bicarbonate buffer system can only buffer ....
Henderson-Hasselbalch equation calculates ....
pH of the bloods bicarbonate buffer system
as long as ratio is 20:1 the pH = ....
acute changes in .... produce a much greater effect on pH than acute changes in ....
H2C03 than HC03
for every 1 molecule of H2C03 increase, there must be a .... molecule increase in HC03- to maintain the pH
if ratio > 20:1 the pH ....
if ratio < 20:1 pH ....
buffer molecules are used up as buffering process occurs, reaction will reach equilibrium & then cease
non bicarbonate (closed buffer system)
Hb can buffer .... & ....
fixed & volatile
what 2 organ compliment each other in maintaining acid base balance
lungs & kidneys
ventilation less than needed to maintain normal PCO2 (PC02 increases)
ventilation in excess of that needed to maintain PCO2 (PC02 decreases)
the kidney compensates for respiratory acidosis by .... & ....
excreting H+ & retaining bicarb to return the ratio to 20:1
the kidney compensates for respiratory alkalosis by ....
excreting HC03- again to return ratio to 20:1
long term COPD patients with chronic hypoventilation may have compensated ....
pH's greater than 7.40
metabolic acidosis is caused by ....
fixed acid loads
compensation for metabolic acidosis occurs by .... & .... (quickly)
hyperventilation & bicarb buffering
metabolic alkalosis can be caused by ....
name 3 things hypokalemia can be caused by:
IV therapy without K+ replacement
kidney attempts to compensate by retaining .... & excreting ....
K+ & H+
patients with hypokalemia exhibit:
metabolic alkalosis, muscle weakness, cardiac arrhythmias
a decrease in Cl- ions causes the kidney to retain HC03- to maintain electrolyte balance
retained HC03- increases ....
kidneys excrete .... which also increases pH
removes HCl from the stomach, increasing pH
vomiting (gastric suctioning)
measure of the metabolic contribution to an acid base disorder
in combined disturbances the pH must be .... & .... is not possible
abnormal & no compensation
list 4 things that should be considered when analyzing a blood gas
effects of current therapy
pathology of diseases
PaC02 > 45 =
PaC02 < 35 =
for every 10 mmHg C02 increases, HC03 increases ....
compensation is complete if ....
the pH has been returned to normal range
partially compensated occurs when the process has begun but the ....
pH hasn't returned to normal range yet
if pH is on acid side of normal then the component that causes acidosis is the .... & other component is ....
primary disturbance & compensating
full compensation is referred to as ....
chronic acid base disturbance
uncompensated disturbances are .... disorders
name the 4 primary disturbances
respiratory acidosis is caused by ....
in uncompensated respiratory acidosis the pH will be ...., PaC02 will be ...., and bicarb will be ....
low, high, elevated
compensation only ....
correction of respiratory acidosis requires an ....
increases in alveolar ventilation
if ratio is > .7 the problem is ....
if ratio is < .3 the problem is ....
if ratio is between .3 and .7 the problem is ....
acute on chronic hypercapnia
respiratory alkalosis is caused by .... which eliminates CO2 at rate greater than its produced
Name 4 causes of respiratory alkalosis
anxiety, fever, pain, CNS injury
what is the most common cause of respiratory alkalosis
induced by treatment
respiratory alkalosis is characterized by :
high pH, low PCO2, & small decrease in HCO3 by hydration reaction
what is an early sign of respiratory alkalosis & hyperventilation?
numb/tingling feeling in extremities, & dizziness
during respiratory alkalosis the kidney compensates by ....
excreting HCO3 in the urine
how do you correct respiratory alkalosis
removing stimulus causing hyperventilation
metabolic acidosis is characterized by :
metabolic alkalosis is characterized by:
Name the 2 ways metabolic acidosis can occur
1. accumulation of fixed acids
2. decrease in HCO3
What is a normal range for anion gap?
8 - 16
the anion gap exists because ....
not all ions are measured
elevates anion gap (>20) indicates ....
metabolic acidosis related to increase in fixed acids
when fixed acids accumulate in the blood they ....
increase the H+
metabolic acidosis caused by bicarb loss does not cause ....
an increase in anion gap because Cl- ions are retained
how do you determine the coexistence of 2 metabolic disorders?
compensation for metabolic acidosis is ....
metabolic alkalosis is characterized by a ....
high bicarb concentration & high pH
name the 2 ways metabolic alkalosis can occur
1. loss of fixed acids
2. gain of blood buffer base
metabolic alkalosis is most commonly caused by ....
loss of acid or hypokalemia
compensation for metabolic alkalosis is ....
related to the metabolic component of blood
base excess (deficit)
.... should be looked at separately from acid base status
Pa02 decreases with ....
.... leads to metabolic acidosis
hyperventilation stimulated by hypoxemia leads to ....
.... must be noted
voluntary control is ....
the .... is believed to originate in the medulla oblongata by 2 groups of respiratory neurons
rhythmic spontaneous ventilator pattern
name the 2 groups of rhythmic spontaneous ventilatory pattern
1. ventral respiratory group
2. dorsal respiratory group
the dorsal respiratory group consists of .... and is responsible for regular rhythmicity of ventilation
the DRG inputs modify the .... and ....
rate and depth of inspiration
ventral respiratory group contains .... and ....
inspiratory and expiratory neurons
during normal quiet breath the VRG neurons are ....
name the 2 respiratory centers in the Pons
1. apneustic center
2. pneumotaxic center
apneuistic breathing indicates ....
damage to the pons
pneumotaxic center controls the ....
off switch point for inspiration
pneumotaxic center enhances the ....
rhythmicity of the breathing pattern
generated by stretch receptors located in the smooth muscle of large and small airways
hering-breuer inflation reflex
hering-breuer reflex is only active at ....
large tidal volumes
compression or deflation of the lungs, stimulates increased rate of breathing
hyperinflating the lungs, causing an increase in inspiratory effort (opposite of hering-breuer)
head's paradoxic reflex
located in epithelium of large airways, reflexes has sensory & motor paths by the Vagus nerve
located in lung parenchyma near pulmonary capillaries
juxtapulmonary-capillary receptors (J receptors)
name 4 things the J receptors are stimulated by
1. pulmonary vascular congestion
2. pulmonary hypertension
4. pulmonary embolism
found in muscles, joints, tendons, send stimulatory signals to the medulla increasing inspiration, pain receptors
.... & .... baroreceptors can increase or decrease ventilation in response to blood pressure changes
aortic & carotid
...., ...., .... stimulate ventilation by activation of various chemoreceptors which send signals to medullary centers, increasing ventilation
hypercapnia, acidemia, hypoxemia
central chemoreceptors located in medulla, respond directly to .... , but are indirectly controlled by ....
H+ , PC02
these chemoreceptors are not in direct contact with arterial blood but with the ....
blood brain barrier is impermeable to .... & .... ions, but permeable to ....
H+ & bicarbonate , C02
in cases of chronic hypercapnia the kidney compensates by ....
no oxygen = no ....
effect on chemoreceptors
.... has no direct effect on central chemoreceptors
located in carotid bodies & aortic arch near baroreceptors
the carotid bodies are more sensitive to .... levels than aortic bodies
carotid bodies respond to .... & not to .... content
Pa02 & 02
peripheral chemoreceptors are not stimulated until the Pa02 ....
drops below 60 mmHg
.... plays no role in ventilatory rate of healthy individuals at sea level
peripheral chemoreceptors also respond to .... & .... levels in the blood to increase ventilation
H+ & C02
peripheral chemoreceptors response occurs .... to changes than central chemoreceptors
Name 5 things responses to peripheral receptors
increased PaC02 dilates ....
C02 levels in head trauma are usually maintained at ....
Name 4 effects of renal failure
4. pulmonary edema
the renal artery, vein, nerves, & ureters enter & exit the kidney at the ....
outer section of the kidney
inner section of the kidney
the renal pyramids contain the .... of the kidneys nephrons
each kidney contains .... nephrons
the nephron consists of ...., .... ,.... ,....
glomerulus, proximal convoluted tubule, loop of henle, & distal convoluted tubule
the distal convoluted tubules empty into the ....
hollow pouch which surrounds the glomerulus
capillary bed formed by afferent arterioles
the glomerulus & bowmans capsule form the ....
determined by glomerular pressure, plasma oncotic pressure, and bowmans capsular pressure (10 mmHg)
glomerular filtration rate (GFR)
a constant GFR is important to adequately ....
eliminate waste products & reabsorb solutes
what is GFR arterial pressure
70 - 160 mmHg
average urine output is ....
H20 moves out into the ....
the volume of urine is affected by the ....
aldosterone causes .... retention and .... excretion
Na+ and K+
the renal tubules are capable of secreting ....
when H+ concentrations decrease the kidneys excrete HC03 to ....
For every H+ excreted an .... is gained by the blood
name the 2 buffers that H+ ions excreted in filtrate
1. phosphate buffer
2. ammonia buffer
name 5 common causes of renal failure
3. obstructive disorders
4. congenital disorders
5. immune responses
infections are most common in ....
urinary tract infection
renal disorders can be classified by ....
where in the renal system they occur
name 4 renal conditions that obstruct blood flow through the kidney
1. renal ischemia
2. intratubular obstructions
3. acute inflammatory conditions
4. glomerular injury
post-renal disorders are usually ....
obstructions in urinary tract
.... can also cause decreased urinary output & renal failure
name the 2 tests for kidney function