Acid base imbalances

Question 1

If the ph of arterial blood rises above 7.45, this would be called

Answer 1

alkalosis

Question 2

if the ph of arterial blood falls below 7.35, this would be called…

Answer 2

acidosis

Question 3

cell death will occur if the ph is higher than… or lower than ….

Answer 3

7.7 and 6.8

Question 4

normal body metabolism produces an excess of acids that need to be removed to retain homeostasis, name 3 acids produced by metabolism

Answer 4

• carbonic acid from CO2 - aerobic respiration
• Lactic acid from anaerobic respiration
• ketones from the use of lipids as an energy source

Question 5

what are the two types of buffer systems that regulate ph homeostasis

Answer 5

• chemical and physiological

Question 6

what is the response time for the chemical buffer systems and name 3 types

Answer 6

• immediate
• bicarbonate
• phosphate
• protein

Question 7

what are the two types of physiological buffer systems and their according response time?

Answer 7

• Respiratory (minutes)

- renal (hours)

Question 8

How do chemical buffers work?

Answer 8

buffers react with a relatively strong acid or base to replace it with a relatively weak one, they do this by either absorbing of releasing hydrogen ions to reduce the change in ph

Question 9

how does the bicarbonate-carbonic acid buffer system work

Answer 9

to maintain normal blood ph, a proportion of 20 bicarbonate ions (HCO3) to 1 carbonic acid (H2CO3) or carbon dioxide is required this reaction is catalysed by carbonic anhydrase in rbc’s

Question 10

how is ph regulated by the respiratory system

Answer 10

if PCO2 in the blood rises it activates the medullary chemoreceptors which cause an increase in respiratory rate and depth, this also happens if there is a rise in plasma H+ which activates the peripheral chemoreceptors having the same effect. both cause more CO2 to be removed from the blood driving bicarbonate-carbonic acid buffer system to the left which reduces hydrogen concentration

Question 11

how does hypoventilation impact ph homeostasis

Answer 11

respiratory acidosis will occur if ph is less than 7.35 due to the retention of CO2 driving the buffer system to the right and therefore raising hydrogen ion concentration

Question 12

how does hyperventilation impact ph homeostasis

Answer 12

respiratory alkalosis will occur if ph is above 7.45 for to much loss of CO2 driving buffer system to the left thereby lowering hydrogen ion oncentration

Question 13

how do the kidney’s regulate homeostasis and what does this buffer system rely on

Answer 13

kidneys can excrete or retain both hydrogen and bicarbonate ions during the filtration process
- this buffer system relies on norml kidney function

Question 14

if either the repiratory or renal system are impaired causing a change in ph, what can happen to help solve this issue

Answer 14

the system not impaired may compensate in an attempt to move ph closures to normal range

Question 15

what are the 3 aspects of naming an acid base disorder

Answer 15

• either be acidosis or alkalosis
• either caused by respiratory or non-respiratory (metabolic)
• can be partly or fully compensated or uncompensated
  eg. compensated respiratory alkalosis

Question 16

what would the ph, CO2 and bicarbonate levels be of a person who has uncompensated respiratory acidosis

Answer 16

ph = less than 7.35
CO2 = increased (greater than 45mmHg)
bicarbonate = normal

Question 17

what would the ph, CO2 and bicarbonate levels be of a person who has uncompensated metabolic acidosis

Answer 17

ph = less than 7.35
CO2 = normal 
Bicarbonate = decreased (less than 22mEq/L)

Question 18

what is a cause of respiratory acidosis

Answer 18

hypopventilation

Question 19

what is 3 causes of metabolic acidosis

Answer 19

• severe diarrhea (loss of bicarbonate ion from gut)
• renal disease ( can remove hydrogen ions properly)
  = diabetic ketoacidosis

Question 20

how can acidosis cause hyperkalaemia? and what is consequence of this ?

Answer 20

• due to hydroge entering cells to exchange for k+ cells leaving into ECF
• acidosis causes and decrease in secretion of k+ from kidney
• hyperkalaemia can cause cardiac arrythimias

Question 21

what will the ph, CO2 and bicarbonate levels be for a person with uncompensated respiratory alkalosis?

Answer 21

• ph = greater than 7.45
• CO2 = decreased (less than 35mmHg)
• bicarbonate = normal

Question 22

what can cause respiratiory alkalosis?

Answer 22

hyperventialtion

Question 23

what would the ph, CO2 and bicarbonate levels show on a blood gas test for somenone who has uncompensated metabolic alkalosis

Answer 23

• ph= greater than 7.45
• CO2 = normal
• Bicarbonate = increased ( greater than 26mEq/L)

Question 24

what are 3 potential causes of metabolic alkalosis?

Answer 24

• vomiting (loss of acid)
• some diuretics cause loss of K+ and H+ at kidney
• overdose of antacids

Question 25

the body will try to compensate if the is an issue with one buffer system to attepmt to maintain homeostasis, how can we tell if this is happening?

Answer 25

• on the blood gases results the amount of HCO3 or H+ will oppose the observed deviation in blood ph

Question 26

what would the ph, CO2 and bicarbonate levels show on the blood gases results of someone who has compensated respiratory acidosis and how is this acheived?

Answer 26

• ph = either normal (if fully compensated) or below 7.35 (if only partly compensated)
• CO2 = increased ( greater than 45mmHg)
• Bicarbonate = elevated
• kidneys retain HCO3 ions and secrete H+ ions

Question 27

what would the ph, CO2 and bicarbonate levels show on the blood gases result of someone who has compensated metabolic alkalosis and how is this achieved?

Answer 27

• ph = either normal (if fully compensated) or above 7.45 (if partly compensated)
• CO2 = elevated
• Bicarbonate = increased (above 26mEq/L)
• the lungs will retain CO2 and therefor increase hydrogen concentration

Question 28

Blood gases are tests used to detect disorders what things are measured in the arterial blood and what would be the normal range for each measurement?

Answer 28

• ph = 7.35 - 7.45
• CO2 (pCO2) = 35 - 45 mmHg
• PO2 = 80-100mmHg
• HCO3 = 22-32mmol/L
• %saturation = 95 100%