Typical changes in total body water in older people include:

A. Immunodeficiency does not directly cause endocrine disorders, although some immune system issues can affect endocrine function, such as in autoimmune diseases.

B. Adenomas (benign tumors) are the most common cause of endocrine disorders, as they can overproduce hormones or disrupt normal gland function, leading to conditions like hyperthyroidism or Cushing's disease.

C. Surgical removal of endocrine glands may cause endocrine disorders, but it is a result of treatment rather than a common cause.

D. Infection can lead to endocrine disorders, particularly in cases of infectious diseases affecting specific glands (e.g., thyroiditis), but it is not the most common cause overall.

A. This option is incorrect because impaired sodium excretion by the kidneys does contribute to increased peripheral vascular resistance and hypertension.

B. Impaired sodium excretion by the kidneys can lead to fluid retention, which increases blood volume. This results in increased peripheral vascular resistance, a key factor in the development of hypertension.

C. Overstimulation of the parasympathetic nervous system typically causes a reduction in heart rate and vasodilation, which would generally lower blood pressure, not contribute to hypertension.

D. The renin-angiotensin-aldosterone system plays a crucial role in regulating blood pressure. Reduced secretion of renin, angiotensin, and aldosterone would not contribute to increased peripheral vascular resistance. In fact, these systems typically work to raise blood pressure when needed.