Pathophysiology

Question 1

Water

Answer 1

Transport for exchange of nutrients/O2/CO2 and wastes, medium for metabolic reactions, regulates body temp, shock absorber, insulation, lubrication

Question 2

Intracellular components

Answer 2

Potassium, magnesium, phosphate

Question 3

Extracellular components

Answer 3

Sodium, chloride, bicarb

Question 4

Normal electrolyte blood levels

Answer 4

Sodium (Na+)- 135-145mEq/L
Chloride (Cl-)- 95-105mEq/L
Bicarbonate (HCO3-)- 22-30mEq/
Calcium (Ca+)- 9-11mg/dL
Potassium (K+)- 3.5-5.3 mEq/L
Phosphate (PO4 2-)- 1.7-2.6mEq/L
Magnesium (MG2+)- 1.5-2.5mg/dl 
Serum osmolality (solute concentrate)- 280-300mosm/kg

Question 5

Osmosis

Answer 5

Fluids move from low solute to high solute.
Isotonic (same solutes and plasma so concentration remains the same
Hypertonic ( greater solutes than plasma, water is drawn out of cells)
Hypotonic-normal Saline (Lower solute than plasma, water moves into cells)

Question 6

Diffusion

Answer 6

Move from high solute to low solute.

Simple or facilitated (move with help of carrier protein)

Question 7

Filtration

Answer 7

Move from high hydrostatic pressure to low hydrostatic pressure.
Hydrostatic pressure in arterial end of capillaries (high pressure pushes fluid into interstitial space, osmotic pressure at venous side of capillary pulls fluid back into capillary)

Question 8

Active transport

Answer 8

Move against concentration gradient with ATP

Question 9

Body fluid regulation mechanism

Answer 9

Thirst- increase in serum osmolality or drop in blood volume triggers thirst centre in brain. Decreases with age and not at all when unconscious

Kidneys- renin-angiotensin, ANP, ADH (increases with pain, anaesthesia, stress, surgery, morphine/barbiturates and mechanical ventilation- release inhibited by ethanol and phenytoin)

Question 10

Acid base balance

Answer 10

Acids release hydrogen ions, bases accept them

Volatile acid (eliminated by metabolism or excretion)= lactic acid, hydrochloric acid, phosphoric acid, sulphuric acid

Question 11

Buffer systems

Answer 11

Bicarb- buffers bind to hydrogen ions
carbonic acid buffer system 20:1 ratio (excess acid=acidosis, excess base=alkalosis)
Cannot be maintained long term

Respiratory buffer- retains or eliminates CO2. Increased resp stimulation in brain for acidosis and depresses for alkalosis
Works within minutes but cannot be maintained long term

Renal system-long term regulation
Eliminates non-volatile acids
Regulate bicarb levels by regenerating bicarb ions or reabsorbing them
Acidosis- kidneys excrete hydrogen ions and retain bicarb vice versa

Question 12

Arterial Blood gas

Answer 12

Normal Ph 7.34-7.45
PaCO2 35-45
PaO2 80-100
Bicarb 22-26
Base excess -3.0- +3.0. Measures substances that can accept hydrogen ions and thus the amount of acid/base that is needed to return to normal pH

Metabolic acidosis- low pH, low bicarb
Metabolic alkalosis- high bicarb/high pH
Resp acidosis- high CO2/ low pH
Resp alkalosis- low CO2/ high pH
Compensation if pH has returned to normal and bicarb or CO2 off
Always follow the pH to find out which is the main system malfunctioning and what is compensating