block 2 lecture 7 acid and base balance

Question 1

what is pH?

Answer 1

hydrogen ion concentration

Question 2

what is stomach acid pH?

Answer 2

2

Question 3

what is the pH of extracellular fluid?

Answer 3

7.4

Question 4

what is the pH of blood?

Answer 4

7.35-7.45

Question 5

what is the pH of blood to sustain life?

Answer 5

6.8-8

Question 6

what is it called if we have a blood pH of below 7.35?

Answer 6

acidosis

Question 7

what is it called if we have a blood pH of above 7.45?

Answer 7

alkalosis

Question 8

at the pH of 7.4 what is the ratio of bicarbonate ions to pCO2?

Answer 8

20:1

Question 9

what happens in the bicarbonate buffer system?

Answer 9

hydrogen ions and bicarbonate ions can be converted into carbonic acid which can dissociate into hydrogen ions and bicarbonate ions

Question 10

the body has 3 buffering systems?

Answer 10

blood buffering system, respiratory system and renal mechanisms

Question 11

what are the buffering systems in the blood?

Answer 11

bicarbonate buffer, phosphate system and protein buffer system

Question 12

what is the buffering system in the respiratory system?

Answer 12

removal of CO2 by ventilation

Question 13

what is the buffering system in the renal system?

Answer 13

excretion of hydrogen ions and reabsorption of bicarbonate ions

Question 14

what is the carbon dioxide concentration regulated by?

Answer 14

lungs

Question 15

what is the bicarbonate ion concentration regulated by?

Answer 15

kidneys

Question 16

what does bicarbonate ion convert a strong acid into?

Answer 16

weak acid

Question 17

what converts strong base into a weak base?

Answer 17

carbonic acid

Question 18

what are the two salts of the phosphate system?

Answer 18

sodium dihydrogen phosphate and disodium dihydrogen phosphate

Question 19

what is the alkaline phosphate salt?

Answer 19

disodium dihydrogen phosphate

Question 20

what is the acidic phosphate salt?

Answer 20

sodium dihydrogen phosphate

Question 21

where is the protein buffer system present?

Answer 21

plasma and blood

Question 22

in the plasma what forms weak acids? (protein buffer system)

Answer 22

carboxylate group and side chains

Question 23

in the erythrocyte what is the buffer?

Answer 23

haemoglobin

Question 24

when does the amino group release hydrogen? (protein buffer system)

Answer 24

in the presence of excess base

Question 25

what accepts a hydrogen atom in the presence of excess acid? (protein buffer system)

Answer 25

carboxyl group

Question 26

what is important about hemoglobin in the protein buffer system?

Answer 26

Deoxygenated haemoglobin has a high capacity to bind to hydrogen ions which is then released when oxygen enters the capillaries. Haemoglobin prevents the fall in pH when more carbon dioxide enters the capillaries.

Question 27

what happens to carbon dioxide in the lungs?

Answer 27

bicarbonate ions and hydrogen ions in the blood form carbonic acid which dissociates into water and carbon dioxide which is then removed by ventilation

Question 28

what happens when metabolic activity increases to pH?

Answer 28

this increases the carbon dioxide concentration ad so the hydrogen ion concentration causing pH to fall

Question 29

what does increased metabolic activity do to ventilation?

Answer 29

lowers pH which is detected by chemoreceptors which stimulate pulmonary ventilation

Question 30

what do the kidneys do in the renal system of buffering in short?

Answer 30

excrete hydrogen ions and reabsorb bicarbonate ions

Question 31

where does bicarbonate reabsorption occur?

Answer 31

proximal convoluted tubule and distal convoluted trubule

Question 32

where does most bicarbonate reabsorption occur?

Answer 32

proximal convoluted tubule

Question 33

what does bicarbonate ions combine with to form carbonic acid? (renal system)

Answer 33

hydrogen ions

Question 34

what dissociates carbonic acid? (renal system)

Answer 34

carbonic anhydrase

Question 35

where do you find carbonic anhydrase? (renal system)

Answer 35

brush border membrane

Question 36

what does carbonic anhydrase dissociate into? (renal system)

Answer 36

carbon dioxide and water

Question 37

where does the carbon dioxide from dissociated carbonic acid go? (renal system)

Answer 37

it diffuses across the apical membrane and the tubular cell

Question 38

what happens to the carbon dioxide in the tubular cell? (renal system)

Answer 38

combines with water and forms carbonic acid

Question 39

what happens to the carbonic acid in the tubular cell? (renal system)

Answer 39

rapidly dissociates into bicarbonate ions and hydrogen ions

Question 40

what is on the apical membrane to remove hydrogen ions?

Answer 40

hydrogen ATPase

Question 41

where do the hydrogen ions go from the hydrogen ATPase? (renal system)

Answer 41

lumen tubule filtrate

Question 42

what happens to the bicarbonate and sodium ions from the tubular cell? (renal system)

Answer 42

pumped across the intracellular space into peritubular capillaries

Question 43

how much reabsorption does the DCT do? (renal system)

Answer 43

10%

Question 44

what does the DCT do? (renal system)

Answer 44

brings about the removal of acid

Question 45

why does the pH fall in the collecting ducts?

Answer 45

the distal nephron is impermeable to hydrogen ions as there

Question 46

what are the mechanisms which try to restore the acid base balance celled?

Answer 46

compensation

Question 47

what are the two compensatory mechanisms called?

Answer 47

respiratory and renal

Question 48

which compensatory system is fast?

Answer 48

respiratory

Question 49

what does respiratory acidosis result from?

Answer 49

accumulation of carbon dioxide due to a failure of pulmonary ventilation

Question 50

what does metabolic acidosis result from?

Answer 50

accumulating non-volatile acid

Question 51

what can respiratory acidosis be caused by?

Answer 51

airway obstruction, COPD, asthma, CNS lesion, anasthesia

Question 52

what can metabolic acidosis be caused by?

Answer 52

formation of acidic ketone bodies, lactic acid build up, reduced ability to excrete acid, diabetes

Question 53

what is respiratory alkalosis?

Answer 53

increase in pH and decrease in blood pCO2, sustained hyperventilation

Question 54

what can cause sustained hyperventilation in respiratory alkalosis?

Answer 54

anxious, hypoxia, high altitude, fever, brain stem damage - pons

Question 55

what can cause metabolic alkalosis?

Answer 55

vomiting, taking antacids

Question 56

what is the other buffer of the renal system?

Answer 56

ammonia

Question 57

what catalyses the production of ammonia?

Answer 57

glutaminase

Question 58

where do you find glutaminase?

Answer 58

PCT

Question 59

what is ammonia produced from?

Answer 59

ammonia rich amino acids

Question 60

how does ammonia help remove hydrogen ions?

Answer 60

ammonia comebines with hydrogen ions forming the ammonium ion which is removed by a carrier protein