Acid-Base

Question 1

normal pH of blood

Answer 1

7.35-7.45

Question 2

What is acidemia

Answer 2

Increased hydrogen ion concentration in blood with pH of less than 7.35

Question 3

What pH is incompatible with life?

Answer 3

6. 9 or less
7. 8 or more

Question 4

Alkalinity

Answer 4

fewer hydrogen ions in blood
pH greater than 7.45

Question 5

What factors impact the body’s ability to maintain homeostasis?

Answer 5

1. length of time of imbalance
2. baseline functioning of organs involved
3. underlying condition resulting in imbalance

Question 6

3 methods the body uses to maintain acid-base homeostasis

Answer 6

1. chemical buffers
2. respiratory regulation
3. renal regulation

Question 7

How do chemical buffers work?

Answer 7

They make acids more weak or bind to acids to neutralize their effects

Question 8

Where are chemical buffers found?

Answer 8

ICF

ECF

Urine

within erythrocytes

Question 9

What are the 3 chemical buffers in the body?

Answer 9

1. carbonate/carbonic acid
2. phosphate
3. plasma protein

Question 10

Which chemical buffers are most abundant?

Answer 10

Plasma protein buffers

Question 11

Describe the bicarbonate-carbonic acid buffer

Answer 11

• Buffer is formed when there are large amounts of both
• normally bicarbonate to carbonic acid ratio is 20:1 (cellular housekeeping produces much more acid)
• Blood is more basic and neutralizes the metabolic acid produced
• if blood gets too acidic, bicarbonate will accept hydrogen ions to form carbonic acid, which is broken into C02 and H20 by enzymes
• if blood is too alkaline, carbonic acid forms bicarbonate and free hydrogen ions, and the body reabsorbs the hydrogen

Question 12

How does respiratory regulation work?

Answer 12

• cells produce Co2, which combines with H20 to form carbonic acid
• chemoreceptors sense change in partial pressure of arterial CO2 and H+.
• Too much carbonic acid = hyperventilation = excess carbonic acid is exhaled
• Too little carbonic acid = hypoventilation = retention of C02

Question 13

What kinds of acids do the kidneys excrete?

the lungs?

Answer 13

Lungs excrete carbonic acid

kidneys excrete all other acids

Question 14

How does renal regulation work (general)?

Answer 14

• acidosis = kidneys increase excretion
• alkalemia = kidneys decrease excretion until acids accumulate to normal level
• takes 2-3 days

Question 15

Mechanisms kidneys use to excrete acids

Answer 15

1. fluid enters glomerular capsule of nephron
2. renal tubular fluid passes through nephron and becomes urine (epithelial cell lining of renal tubule is a filter: allows substances to diffuse into tubule for excretion or reabsorbed into interstitial fluid)
3. at proximal tubules: epi cells secrete H+ ions into the tubule
4. For each H+ ion secreted into the tubule, 1 bicarbonate is diffused into interstitial fluid
5. H+ ions combine with bicarbonate, phosphate buffers, and ammonia (creates non-lipid soluble ions that can’t easily cross back into the interstitial space)