Question

Was the Bainbridge reflex initiated in the subject? In your rationale, describe the expected changes that occur as a result of the Bainbridge reflex (start with deep inhalation and end with the expected change in heart rate that characterizes the Bainbridge reflex) – how does each step in the process lead to the expected change in heart rate: include receptors and ion channels involved.

Answer 1

the bain bridge reflex is also called the artrial reflex, is an increase in heart rate due to increase in central ventral pressure.

increased blood volume is detected by stretch receptors (cardiac receptors) located in both atria and venoartrial junction.

yes, bainbridge reflex initiated in the subject.

changes

bainbridge reflex is involved in respiratory sinus arrhythmia.

during inhalation interthoracic pressure decreases.

it triggers increase venous returns which is registered by stretch receptors , which via bainbridge reflex increases heart rate momentarily during inspiration.

as increased blood volume results in increased venous return to the heart, which leads to increased firing of B fibres,

B fibres sends signals to the brain which then modulate both symphatic and parasymphatic pathways to the SA node of the heart, causing an increase in heart rate.

effects on cardiac contractility and stroke volume are insignificant.

venous returns(changes in heart)

as the venous return increases , the pressure in the superior and inferior vana cava increase.

this results in an increase in the pressure of right artrium , which stimulates the artrial stretch receptors.

these receptors in turn signal the medullarly control centres to increase the heart rate(tachycardia) .

unusually , this tachycardia is mediated by increased symphatic activity to the sinoartrial node(SAN) with no fall in parasympathetic activity.

increasing in the heart rate serves to decrease the pressure in the superior and inferior vanae cavae by drawing more blood out of the right artrium.

this results in decrease in artrial pressure, which serves to bring more blood from the vena cavae, resulting in a decrease in the venous pressure of the great veins.

this continues until right artrial pressure returns to normal levels, upon which heart rate decreases due to its original level.