A client diagnosed with essential hypertension asks the nurse what exactly is measured by taking a blood pressure. The nurse explains to the client that blood pressure is a reflection of pressure in which of the following?

Correct Answer: A

Rationale: Blood pressure is a measurement of the pressure exerted by the blood being pumped by the heart into the blood vessels, specifically measured in the larger arteries. Blood pressure may be influenced by the heart and intrathoracic pressure, but is accurately defined as pressure within the blood vessels. (Source: Document, Pretest Answer 5, p. 76)

Correct Answer: D

Rationale: Erythrocytes number ~25 trillion, are biconcave discs, and hemoglobin is ~15% of blood weight (close to one-sixth), but citric acid is not a key component (heme and globin are). This statement is untrue.

Correct Answer: D

Rationale: Hemostasis includes vasoconstriction (smooth muscle), platelet adhesion, and clot retraction. The renin-angiotensin system regulates blood pressure, not directly involved in hemostasis.

Correct Answer: C

Rationale: Adrenaline (epinephrine) increases heart rate (chronotropy), contraction force (inotropy), and oxygen demand via β-adrenergic stimulation. However, it increases myocardial irritability (risk of arrhythmias), not decreases it, making C the exception.

Correct Answer: D

Rationale: The cardiac cycle is the sequence of mechanical and electrical events between one heartbeat and the next , including systole and diastole (~0.8s at 75 bpm). A is too broad, B is cardiac output, C is ECG-specific, and D is heart sound-specific, not the full cycle.