Fluid and electrolytes

Question 1

Most common EXTRACELLULAR (plasma) cation and anion?

Answer 1

Cation: Na+
Anion: Cl-

Question 2

Most common INTRACELLULAR cation and anion?

Answer 2

Cation: K+
Anion: PO4 3-

Question 3

How does the RAAS system work?

Answer 3

1. Liver releases angiotensinogen
2. Juxtaglomerular cells of the kidney release renin which convert angiotensinogen to angiotensin I
3. Angiotensin converting enzyme (ACE) in the lungs converts angiotensin I to angiotensin II
4. Angiotensin II acts on the adrenal cortex to simulate release of aldosterone
5. Aldosterone act on the kidneys to increase sodium and water retention
6. This increases blood pressure

Question 4

Fluid volume excess assessment findings:

Answer 4

• peripheral oedema
• bounding pulse
• weight gain
• dyspnoea/orthopnoea/cough

Question 5

Fluid volume deficit assessment findings:

Answer 5

• decreased skin and tongue turgor
• decreased oral cavity moisture
• decreased urine output
• decreased weight

Question 6

Normal blood pH:

Answer 6

7.35-7.45

Question 7

Acidosis:

Answer 7

• lack of bicarbonate

- RR increases to blow of CO2 (acid)

Question 8

Alkalosis:

Answer 8

• excess bicarbonate

- RR decreases to retain CO2 (acid)

Question 9

Buffer system:

Answer 9

• If CO2 levels are off = respiratory problem
• If HCO3- levels are off = metabolic problem
• If both are off = there is compensation occurring
• Eg. If pH is low –> acidosis, if CO2 is high –> caused by lungs, if HCO3- is normal –> kidneys are not compensating: therefore, uncompensated respiratory acidosis.

Question 10

Potassium

Answer 10

Chief regulator of cellular enzyme activity and water content

Question 11

Sodium

Answer 11

Controls and regulates volumes of body fluids; maintains water balance

Question 12

Calcium

Answer 12

Nerve impulses; blood clotting and muscle contraction

Question 13

Magnesium

Answer 13

Metabolism of carbohydrates and protein, involved in vital reactions involving enzymes

Question 14

Chloride

Answer 14

Acts with sodium to maintain osmotic pressure in blood; plays a role in acid-base balance

Question 15

Bicarbonate

Answer 15

Body’s buffer system

Question 16

Phosphate

Answer 16

Helps maintain acid-base balance and is involved in important chemical reactions in body and cell division

Question 17

Define diffusion and give two types:

Answer 17

• Diffusion is the movement of molecules from areas of high concentration to low concentration
• Simple diffusion: no external energy
• Facilitated diffusion: use of carrier in cell membrane, no external energy required

Question 18

Define active transport

Answer 18

Process that requires external energy

Eg. sodium-potassium pump utilising ATP

Question 19

Osmosis:

Answer 19

Movement of water from an area of low solute concentration to high solute concentration across a semipermeable membrane

Question 20

Hypertonic vs hypotonic

Answer 20

Hypertonic: low water content outside RBCs causes water to leave RBCs and they shrivel
Isotonic: normal
Hypotonic: high water content extracellularly causes water to enter RBCs and they expand and can sometimes burst