Blood Pressure Essay

1370 Words Nov 27th, 2014 6 Pages
Blood pressure is: the force of the blood exerted against the walls of arteries.
A decrease in blood volume will cause a decrease in blood pressure. There are specialized receptors in the body that are able to detect whether blood pressure is going up or down and these are called baroreceptors. Baroreceptors are found in 3 different places; the carotid arteries, aortic arch and the kidneys. The baroreceptors in the carotid arteries watch the blood pressure in the head, the aortic arch baroreceptors measures pressure in the peripheral body and the baroreceptors in the kidneys monitor abdomen and pelvic pressure. If the blood pressure drops, the baroreceptors will send a signal to the cardiac center in the medulla oblongata. The medulla
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Calcium gates on the sarcoplasmic reticulum open causing the artery to vasocontrict and decreasing the diameter of the artery to ½ its normal size. When the artery constricts to ½ its size the peripheral resistance increases by 4 times. Peripheral resistance is the friction to flow of the blood against the walls of an artery. The blood in the center of the artery flow pretty good but the closer the blood is to the walls of the artery, the more friction it has to move against, causing pressure on the walls of the artery itself. The more peripheral resistance the faster the blood is forced to flow, the faster the flow of blood and the higher the blood pressure (BP). It can also be written as BP= PR x CO

Stroke Volume (SV)
Stroke volume has two parts and can be written as : Stroke Volume=end diastolic volume – end systolic volume. (SV=EDV-ESV). The end diastolic volume is how much blood is in the ventricle after diastole, when all the valves are closed and the ventricles are full. End systolic volume is the volume of blood in the ventricle after the ventricles contract, and can be measured as mL per beat.
To increase end diastolic volume epi and norepi will bind to receptors on the skeletal, smooth and cardiac muscle causing Ca2+ gates in the sarcoplasmic reticulum to open and

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