Question

Please explain if the following would INCREASE or DECREASE blood pressure and HOW:
a. Stress (from this exam) which stimulated the release of norepinephrine and epinephrine from your adrenal medulla -
b. The release of ADH (antidiuretic hormone) -
c. Arteriosclerosis –

Answer 1

1. Stress increases the blood pressure.

Adrenaline is secreted by the adrenal medulla. It is also released by sympathetic postganglionic nerve endings. It increases systolic pressure by increasing the force of contraction of the heart and cardiac output. It decreases diastolic pressure by reducing the total peripheral resistance. Adrenaline causes constriction of blood vessels through alpha receptors. It also causes dilatation of blood vessels through β2receptors in some areas of the body like skeletal muscle, liver and heart. So, the total peripheral resistance is reduced leading to decrease in diastolic pressure

Noradrenalineis secreted by the adrenal medulla. It is also released by sympathetic postganglionic nerve endings. Noradrenaline increases diastolic pressure due to its general vasoconstrictor effect . It has stronger effects on blood vessels than on the heart. It causes constriction of all blood vessels throughout the body via alpha receptors. The action of noradrenaline is to increase the total peripheral resistance and diastolic pressure. It also increases the systolic pressure by increasing the force of contraction of heart.

2. Vasopressin or ADH, which is secreted by posterior pituitary has a potent action on the blood vessels, particularly the arteries. It causes constriction of the arteries in all parts of the body. Due to the vasoconstriction, the blood pressure is increased. However, the amount of this hormone required to cause the vasopressor effect is very much high than the amount required to cause the antidiuretic effect.

3. Arteriosclerosis is the thickening, hardening, and loss of elasticity of the walls of arteries that generally occurs in the old age. It leads to narrowing of vessels which increases the peripheral resistance and increases blood pressure