Acid Base Regulation

Question 1

pH is a measure of ____ and is a function of ____

Answer 1

• acidity

- [H+]

Question 2

pH range of ECF in body is…

Answer 2

6.8 - 7.8

Question 3

Plasma pH is usually around…

Answer 3

7.35 - 7.45

Question 4

Definition of acid:

Answer 4

substance that donates H+

Question 5

Acidosis occurs when blood pH is…

Answer 5

< 7.35

Question 6

Definition of base:

Answer 6

substance that removes H+ from body fluids

Question 7

Alkalosis occurs when blood pH is…

Answer 7

> 7.45

Question 8

Which factors produce changes in ECF pH?

Answer 8

• metabolic factors
• respiratory factors (CO2)
• changes in kidney excretion of bicarb and H+

Question 9

How does metabolism of fats and carbs affect pH?

Answer 9

• large amount of CO2 is created
• volatile acid creates H+
• eliminated by lungs

Question 10

How does metabolism of amino acids affect pH?

Answer 10

• creates sulfuric acid and HCl

- has nonvolatile acid (offset by production of HCO3-)

Question 11

A meat containing diet will have a net acid production that is greater/less than HCO3-

Answer 11

greater than

Question 12

Abnormal insulin levels leads to the production of…

Answer 12

ketoacids

Question 13

How does CO2 have an effect on pH?

Answer 13

• inversely related to pH

- hypoxia -> increased acids

Question 14

How does changes in kidney excretion affect pH?

Answer 14

• acid addition > excretion = acidosis

- acid removal > excretion = alkalosis

Question 15

pH is regulated by…

Answer 15

• buffers
• respiratory rate and depth
• kidney excretion of H+ and bicarb ions

Question 16

What is the first line of defense for changes in pH?

Answer 16

buffers: minimize change in pH when acids are added

- neutralizes acid or base but doesn’t eliminate it from body

Question 17

T/F: ECF buffering occurs slowly

Answer 17

F, it’s instantaneous

Question 18

Steps of bicarb buffering system:

Answer 18

1. CO2 produced and reacts with ECF water to make carbonic acid
2. carbonic acid dissociates into H+ and bicarb
3. increasing ECF bicarb pushes reaction to the left to prevent H+ release

Question 19

What is the rate limiting reaction in the steps of the bicarb buffering system?

Answer 19

hydration of CO2

- gets sped up by carbonic anhydrase

Question 20

What is the principal ECF buffer?

Answer 20

bicarb

Question 21

Normal bicarb concentration range:

Answer 21

23-25 mEq/L

Question 22

Bicarb is regulated by both the…

Answer 22

lungs and kidneys

Question 23

What does buffering processes create and remove?

Answer 23

• creates Na+ salts

- removes bicarb

Question 24

How do the kidneys help with buffering?

Answer 24

• excretes acid salts

- returns bicarb to blood

Question 25

How does the respiratory system help with buffering?

Answer 25

clears CO2 via respiration | - mostly intracellularly

Question 26

Aside from bicarb, what are some other ECF buffers?

Answer 26

- phosphate | - plasma proteins

Question 27

What is the second line of defense against changes in pH?

Answer 27

respiratory regulation of pH | - occurs because of changes to pCO2

Question 28

What determines the pCO2 in the body?

Answer 28

ventilation rate | - increased = decreased pCO2

Question 29

What are important regulators during respiratory regulation?

Answer 29

- blood pCO2 | - pH

Question 30

Blood pCO2 and pH are monitored by...

Answer 30

- central chemoreceptors (medulla for CSF) | - peripheral chemoreceptors (aortic and carotid bodies for plasma)

Question 31

Effect of metabolic acidosis on ventilation rate?

Answer 31

- increased to clear CO2 | - occurs after several minutes

Question 32

Effect of metabolic alkalosis on ventilation rate?

Answer 32

decreased

Question 33

What is the third line of defense against changes in pH?

Answer 33

renal regulation | - takes a few days to return to normal

Question 34

Bicarb is _____ if body is basic, and ______ if body is acidic

Answer 34

- excreted | - reabsorbed

Question 35

What is the primary urinary buffer?

Answer 35

phosphate

Question 36

Phosphate is under regulatory control of...

Answer 36

- thyroid calcitonin (TCT) | - parathyroid hormone (PTH)

Question 37

How does bicarb get formed?

Answer 37

1. CO2 diffuses from plasma into PCT | 2. carbonic anhydrase creates H+ and bicarb

Question 38

How does glutamine produce new bicarb?

Answer 38

1. systemic acidosis stimulates glutamine metabolism in PCT after bicarb loss 2. 2 NH4+ created 3. gets secreted and bicarb gets returned to circulation

Question 39

How many bicarbs are created from metabolism of one glutamine?

Answer 39

2

Question 40

Signs of metabolic acidosis:

Answer 40

- decreased [bicarb] - decreased blood pH - increased [anion]

Question 41

Compensatory mechanisms for metabolic acidosis:

Answer 41

- buffers - increase respiration rate - kidney reabsorbs more bicarb - increase urine [NH4+], which makes more bicarb

Question 42

Signs of metabolic alkalosis:

Answer 42

- increased [bicarb] | - increased blood pH

Question 43

How does metabolic alkalosis occur?

Answer 43

- vomiting - ingestion of alkali - hemorrhage

Question 44

Compensatory mechanisms for metabolic alkalosis:

Answer 44

- buffers - decrease in respiration - increase excretion of bicarb by decreasing reabsorption

Question 45

Signs of respiratory acidosis:

Answer 45

- increased pCO2 | - decreased blood pH

Question 46

How does respiratory acidosis occur?

Answer 46

- poor gas exchange across alveoli | - impaired gas diffusion

Question 47

Compensatory mechanisms for respiratory acidosis:

Answer 47

- ICF buffering - increased bicarb reabsorption - increased NH4+ excretion

Question 48

Signs of respiratory alkalosis:

Answer 48

- decreased pCO2 | - increased blood pH

Question 49

How does respiratory alkalosis occur?

Answer 49

increased gas exchange

Question 50

Compensatory mechanisms for respiratory alkalosis:

Answer 50

- ICF buffering - decreased excretion of bicarb - decreased NH4+ excretion