Final Answer:
Hypertension abnormally increases Systemic Vascular Resistance (SVR). The heightened SVR, influenced by factors like vessel constriction, raises the resistance encountered by blood circulation.Thus the correct option is B. Systemic vascular resistance (SVR).
Step-by-step explanation:
Hypertension, or high blood pressure, primarily affects the cardiovascular system. The key factor influenced by hypertension is the Systemic Vascular Resistance (SVR). SVR is the resistance the blood encounters as it circulates through the systemic circulation. It is determined by factors like vessel diameter and blood viscosity.
According to Poiseuille's Law, SVR is directly proportional to the length and viscosity of the blood vessel and inversely proportional to the fourth power of the vessel radius (SVR = 8ηL / πr^4). When blood pressure increases, it results in arterial constriction, leading to an elevation in SVR. This increased resistance makes it harder for the heart to pump blood throughout the body.
Elevated SVR triggers compensatory mechanisms, such as an increase in the workload of the heart. To overcome the heightened resistance, the heart responds by increasing stroke volume rather than heart rate. Stroke volume is the amount of blood ejected by the left ventricle in one contraction.
Consequently, hypertension doesn't necessarily directly increase heart rate, as the body prefers adjusting stroke volume to maintain cardiac output. The increased workload on the heart, combined with elevated SVR, contributes to the detrimental effects associated with hypertension, such as myocardial hypertrophy and an increased risk of cardiovascular events like strokes and heart attacks.
In summary, hypertension primarily affects SVR due to changes in vessel diameter and blood viscosity. The resulting increased resistance prompts compensatory mechanisms, mainly an elevation in stroke volume rather than heart rate. This understanding provides insights into the physiological consequences of hypertension and underscores the importance of managing this condition to prevent cardiovascular complications.
Thus the correct option is B. Systemic vascular resistance (SVR).