Acid-Basics 1: Intro to pH basics and buffer systems (AS lecture) Flashcards

1
Q

what is the pH range of systemic arterial blood and what is the “normal” pH

A
  • 7.35-7.45
  • normal = 7.4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is acidosis, what can this manifest as physiologically in the CNS and what can this lead to?

A
  • acidosis: blood pH lower than 7.35
  • manifests as depression of the CNS due to depression of synaptic transmission
  • can lead to comas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is alkalosis, and can it lead it physiologically in the PNS and CNS and what 3 ways can this manifest in patients?

A
  • alkalosis: blood pH above 7.45
  • leads to overexcitability of the PNS and then CNS through facilitation of synaptic transmission

This can manifest as:
- spasms
- convulsion
- death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

pH

define pH in a sentence

A

pH is the power of Hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what are the 2 equations for pH

A

pH = -log10([H+])

OR

pH = log10(1/[H+]

where:

  • [H+] is concentration of Hydrogen ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the equation for the hydration of CO2

A

CO2 + H2O (enzyme: carbonic anhydrase) <—> H2CO3 <—> H+ + HCO3-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are 3 ways metabolism produces acid and give 1 example of each

A
  1. Carbonic acid (volatile acid production):
    - Example: hydration of CO2 which happens when we breathe
  2. non-volatile acids (nutrient breakdown):
    - example: protein metabolism
  3. organic acids from intermediate metabolism:
    - example: lactic acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how much carbonic acid and non volatile acid is produced everyday

A

Carbonic acid: 13000 mmol/day

non-volatile acid: 50-80 mmol/day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are 3 lines of defence against pH disorders (abnormal pH change)

A
  1. chemical buffers
  2. adjusting ventilation to change PaCO2
  3. kidneys adjusting renal acid or alkali excretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

give 4 examples of chemical buffers

A
  • albumin
  • haemoglobin
  • carbonic acid
  • phosphates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how much of the way does adjusting ventilation to change PaCO2 restore pH to normal levels

A

restores pH 50-75% of the way

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what type of regulation is the kidneys adjusting renal acid or alkali excretion?

A

long term reguation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how long does each line of defence against pH disorders take?

A

chemical buffers:
- fractions of a second

adjusting ventilation:
- minutes

adjusting renal acid/alkali excretion:
- hrs/days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the drawback to haemoglobin as a chemical buffer?

A

it is limited in quantity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the drawback of the phosphate chemical buffer system

A

it is limited in quantity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are 2 advantages of the Bicarbonate buffer system over the other extracellular buffer systems

A
  • easily regulated
  • highly abundant
17
Q

what are the 3 main extracellular buffer systems

A
  • protein buffer system
  • phosphate buffer system
  • carbonic acid-bicarbonate buffer system
18
Q

what is the main extracellular buffer system

A
  • carbonic acid-bicarbonate buffer system