Thank you for reporting, we will resolve it shortly
Q.
In old age arteries carrying blood in the human body become narrow resulting in an increase in the blood pressure. This follows from
Mechanical Properties of Fluids
Solution:
According to the equation of continuity,
$A v=$ constant
It means, as area increases, velocity also decreases.
Thus, as blood flows from narrow arteries to wider one, velocity decreases. According to Bernoulli's theorem
$P+\frac{1}{2} \rho v^{2}$ = constant
It means, as velocity decreases, pressure increases. Thus, when arteries become narrow, blood pressure increases.