The principal cation in the extracellular fluid is:

1. Ca2+	2. K+
3. Mg2+	4. Na+

Increased stretching of the atrial wall, due to increased atrial blood volume, stimulates the release of:

Serum potassium concentrations are the most potent stimulator of secretion of:
1. Aldosterone
2. Angiotensin II
3. ADH
4. Atrial natriuretic hormone

The humoral stimulus for the secretion of aldosterone is:
1. elevated blood ${\mathrm{Na}}^{+}$ ion levels.
2. decreased blood ${\mathrm{Cl}}^{-}$ ion levels.
3. elevated blood ${\mathrm{K}}^{+}$ ion levels.
4. decreased blood ${\mathrm{Ca}}^{2+}$ ion levels.

An increased production of dilute urine will be the result of:
1. decreased ADH secretion
2. increased renin secretion
3. increased insulin production
4. increased aldosterone secretion

Which of the following contributes maximum to the buffer capacity of human body?
1. carbonic acid/bicarbonate buffer system.
2. phosphate buffer system.
3. protein buffer system.
4. oxygen/carbondioxide buffer system.

What is expected to happen to the pH of urine if the pH of the blood gets acidic?
1. Decreases.
2. Increases.
3. Remains the same.
4. First increases and than decreases.

Highest concentration of proteins are expected to be found in:
1. lymph
2. urine
3. cerebrospinal fluid
4. intracellular fluid

Dehydration in human body will:
1. inhibit the thirst center
2. cause stomach distention
3. stimulate osmoreceptors in the hypothalamus
4. inhibit ADH secretion

ADH will not be secreted due to:
1. ingesting more water than is needed to balance water loss
2. stimulation of hypothalamic osmoreceptors
3. loss of body fluid
4. increased blood osmolarity