Question

During high blood pressure, regulations of heartbeat and circulation are controlled by
(1) Vasodilator and vasoconstrictor centres
(2) Cardiostimulatory and vasoconstrictor centres.
(3) Cardio-inhibitory and vasoconstrictor centres
(4) Cardio-inhibitory and vasodilator centres.

Answer 1

The vasomotor centre is located in the brain stem. It consists of four basic lower brain centres, the cardiac accelerator centre, the cardiac inhibitory centre is the dorsal motor nucleus of the vagus nerve, located below the hypothalamus, the vasoconstrictor centre is located in the medulla oblongata, the vasodilator centre is also located in the medulla oblongata. The cardiac accelerator centre innervates (via sympathetic fibres) the SA node and the ventricular wall. Thus, stimulation of the cardiac accelerator centre results in increased heart rate and increased contractile (i.e., stroke volume). The cardiac inhibitory centre innervates the SA node, but via parasympathetic fibres. Thus, the stimulation of the cardiac inhibitory centre stimulates a decrease in heart rate. Stimulation of the rostral and lateral portions (pressor area) of the vasoconstrictor centre results in vasoconstriction whereas stimulation of the smaller portion around the obex (depressor area) produces vasodilation.

So, the correct answer is option D.

Answer 2

Option (4) is Right Answer

Explanation:

   (4) Cardio-inhibitory and vasodilator centres

• The vasomotor center is situated in the mind brain stem
• It comprises of four essential lower brain centers, the cardiovascular quickening agent center, the heart inhibitory focus is the dorsal engine core of the vagus nerve, situated underneath the nerve center
• The vasoconstrictor place is situated in the medulla oblongata, the vasodilator community is additionally situated in the medulla oblongata
• The heart quickening agent focus innervates (through thoughtful strands) the SA hub and the ventricular divider
• The incitement of the cardiovascular quickening agent focus brings about expanded pulse and expanded contractile (i.e.stroke volume)
• The heart inhibitory focus innervates the SA hub, yet through parasympathetic filaments
• The incitement of the cardiovascular inhibitory focus invigorates a decline in pulse
• The Incitement of the rostral and sidelong parts (pressor zone) of the vasoconstrictor place brings about vasoconstriction while incitement of the littler segment around the obex (depressor territory) produces vasodilation