Respiratory System + Renal System Control Mechanisms

Question 1

respiratory center overview

Answer 1

• located in medulla (brainstem)
• chemoreceptors monitor CO2 level in blood
• -> control adding of O2 to blood + removal of CO2 from blood
• -> regulates breathing rate to maintain steady pH

Question 2

reactions occurring in blood / blood cells (3)

Answer 2

1. CO2 in red blood cells + H20 –> carbonic acid (H2CO3)
2. carbonic acid dissolves in water to form H+ and bicarb ions

–> CO2 transported in blood as bicarb ions

Question 3

full formula of reactions occurring in blood

Answer 3

CO2 + H2O < – > H2CO3 < – > H+ + HCO3-

Question 4

how CO2 affects blood pH

Answer 4

CO2 transported in blood as bicarb ions along with H+, which changes the pH of blood

more CO2 –> higher PCO2 –> more H+ –> lower pH (more acidic)
less CO2 –> lower PCO2 –> less H+ –> higher pH (more basic)

Question 5

PCO2

Answer 5

pressure of CO2 in blood (measured in mm)

Question 6

normal PCO2 range

Answer 6

35-45mm

Question 7

PCO2 < 35 signifies

Answer 7

respiratory alkalosis

Question 8

PCO2 > 45 signifies

Answer 8

respiratory acidosis

Question 9

respiratory control mechanism’s response to acidosis

Answer 9

hyperventilation (increased respiratory rate to expel extra CO2)

Question 10

respiratory control mechanism’s response to alkalosis

Answer 10

hypoventilation (decreased respiratory rt until more CO2 accumulates)

Question 11

renal control mechanisms overview

Answer 11

• kidneys can directly remove acids and bases from body to maintain pH level by reabsorbing or excreting bicarbonate ions
• renal system is slower acting that the other two systems, but has a much larger overall impact on the pH level

Question 12

renal response if blood pH too low

Answer 12

reclaim bicarb ions from filtrate to be absorbed into blood stream via peritubular capillaries (increased bicarb in blood will raise pH)

Question 13

renal response if blood pH too high

Answer 13

keep bicarb ions in filtrate for excretion while reclaiming H+

Question 14

normal range of HCO3 - in blood

Answer 14

22-26 mEq/L