ch 24 smartbook questions

Question 1

which ion is the principal cation of the ECF

Answer 1

sodium

Question 2

which is referred to as the “salt-retaining hormone” because it plays the primary role in adjusting sodium excretion

Answer 2

aldosterone

Question 3

choose all the reason why electrolytes physiologically important

Answer 3

• they affect the osmolarity of the body fluids
• they are chemically reactive and participate in metabolism
• they determine the electrical potential across cell membranes

Question 4

what are the primary effects of aldosterone on urine composition

Answer 4

• decreases NaCl
• increases K+
• decreases pH

Question 5

choose all that are affected by aldosterone

Answer 5

• blood volume
• blood pressure
• urine volume

Question 6

choose all statements that are true regarding fluid sequestration

Answer 6

• causes of fluid sequestration include edema and hemmorage
• it is a condition in which excess fluid accumulates in a particular location

Question 7

choose all that stimulate the secretion of aldosterone

Answer 7

• hyperkalemia
• hypotension
• hyponatermia

Question 8

choose all that are functions of potassium

Answer 8

• it is an essential cofactor for protein synthesis and some other metabolic processes
• it plays a role in cotransport and thermogenesis via the Na+-K+ pump
• it is the greatest determinant of intracellular osmolarity and cell volume
• it helps produce the resting membrane potential and action potentials of nerve and muscle cells

Question 9

even though aldosterone ____ the tubular reabsorption of sodium and water, this is offset by an _____ in GFR; thus there is only a small _____ in urine output

Answer 9

• increases
• increase
• decrease

Question 10

aldosterone stimulates which of the following

Answer 10

• renal reabsorption of sodium
• renal secretion of potassium

Question 11

which hormone inhibits the secretion of renin

Answer 11

natriuretic peptides

Question 12

match each type of potassium imbalance to its neurological effects

Answer 12

• slow-onset hyperkalemia: voltage-gated channels inactivate. this prevents the firing of action potentials
• hypokalemia: the concentration gradient for K+ across the membrane become steeper, resulting in hyperpolarization. This makes neurone and muscle cells less excitable
• rapid-onset hyperkalemia: neurons and muscle cells depolarize suddenly and fire action potentials. Synchronous activation of cardiac muscle cells can lead to cardiac arrest

Question 13

choose all that are possible causes of hypokalemia

Answer 13

• excessive use of laxatives
• alkalosis
• heavy sweating, chronic vomiting, or diarrhea
• aldosterone hypersecretion

Question 14

choose all that can lead to a sudden increase in extracellular potassium

Answer 14

• a transfusion with outdates blood in which K+ has leaked out during storage
• a crush injury
• hemolytic anemia

Question 15

choose all the statements that true regarding potassium homeostasis

Answer 15

• potassium homeostasis is closely linked to that of sodium
• aldosterone stimulates renal secretion of potassium

Question 16

what is a common effect of hypokalemia

Answer 16

loss of muscle tone

Question 17

in the heart calcium sustains ventricular _____ long enough to ensure effective ejection of blood

Answer 17

contraction