Question

1) What happens to your heart rate as you move from laying down to sitting to standing?

2) How does change in heart rate help maintain blood pressure in the caratoid arteries and what component of the autonomic nervous system would most likely elicit the heart rate change?

3) What happens to blood pressure as you move from laying down to sitting to standing? What type of autonomic response would cause a change in BP (sympathetic or parasympathetic)?

Answer 1

1) When we move from laying down to sitting to standing, heart rate gradually increases.

2) Baroreceptors--> pressure?sensitive sensory receptors, are located in the aorta, internal carotid arteries (arteries in the neck that supply blood to the brain), and other large arteries in the neck and chest.

-They send impulses to the cardiovascular center to help regulate blood pressure.

Sympathetic stimulation increases the heart rate and strengthens the heart contractions to increase cardiac output by releasing epinephrine and norepinephrine. This is the component of autonomic nervous system that elicit the heart rate change.

3) It can cause orthostatic hypotensions which is a blood pressure that decreases when the patient sits or stands causing a patient to feel faint.

Its a term used when pressure drops more than 20 mm Hg or the pulse increases by 20 beats per min or more when patient moves from a lying down/recumbent to a standing position.

Baroreflex induced changes in blood pressure are mediated by both branches of the autonomic nervous system: the parasymphathetic and sympathetic nerves.