Acid-Base and Electrolyte Balance Flashcards Preview

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Flashcards in Acid-Base and Electrolyte Balance Deck (18)
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1

What are electrolytes?

Minerals present in blood and other body fluids
They play a vital role in the functioning of the human body

2

2 ways water is regulated by the body

1. Thirst center
2. ADH/Vasopressin

3

Thirst center

In the hypothalamus
Senses an increase in osmolarity --> increases thirst and water intake --> restore osmolarity back to normal

4

Antidiuretic Hormone

Released from the posterior pituitary gland in response to an increase in osmolarity or decrease in BP
Increases the number of aquaporins in the kidneys (increases water retention to restore balance)

5

Most Na is reabsorbed in which 2 places?

Proximal convoluted tubule
Thick ascending limb

6

Aldosterone

Released from the adrenal gland
Stimulates Na reabsorption in the distal convoluted tubule/collecting duct in exchange for K
Water follows Na

7

Natriuretic peptides

Atrial and brain natriuretic peptides
Release from the heart
Activated by myocardial stretch
Decrease Na reabsorption in the DCT/collecting duct
Decrease renin (and hence aldosterone)
Net effect is a decrease in plasma Na and volume

8

Na concentration
1. Extracellular
2. Intracellular

1. 135-145 mM
2. 4-10 mM

9

Hyponatremia

When plasma [ ] is less than 135 mM
Can be from Na depletion, water excess, or Na and water retention (but more water than Na is retained)

10

K concentrations
1. Extracellular
2. Intracellular

1. 3.5-5.0 mM
2. 150 mM

11

3 things that can cause significant K shift

Acid base balance
Insulin
Beta-adrenergic agonists

12

Normal H+ concentration in arterial blood

35-45 nmol/L
Arterial pH is slightly alkaline

13

2 reasons for tight regulation of pH

Proper enzyme structure and function
H+ gradient between inner and outer mitochondrial membrane drives ox phos

14

5 main acids produces by the body

Carbonic acid
Sulphuric acid
Phosphoric acid
Ketoacids
Lactic acid

15

4 buffers in the body and which ones are the main intra or extra cellular ones

Bicarbonate (major extracellular buffer)
Phosphate
Protein
Hemoglobin (major intracellular buffer)

16

For an arterial sample
1. Normal pH
2. Normal pCO2
3. Normal HCO3-

1. 7.35-7.45
2. 35-45 mmHg
3. 21-28 mmol/L

17

Metabolic disorders are compensated by...
How fast?

Compensated by the lungs (change in ventilation rate)
Take effect within seconds to minutes of pH change

18

Respiratory disorders are compensated by...
How fast?

Compensation by the kidneys (change excretion/reabsorption of H+/bicarb)
Requires hours to days to take effect