Response Of The Human Cardiovascular System

This experiment was carried out as noted about in Procedure 1. The resting heart rate was established and used as a baseline value from which to compare all future deviations. While data could

I now know that the hypotension is caused by vasodilatation because the sympathetic nerves that control tone are blocked. Peripheral

It is hypothesized that if subject #3 is reclining for 3 minutes, their arterial rate and heart rate will decrease because their body is relaxing and their heart is not doing any work. This drop is caused by the PNS system sending a signal to the cardioinhibitory center to lower heart rate. When the body is at rest, HR does not need to be increased. While the subject was sitting quietly, the baseline BP and HR was taken. BP was 105 mmHg and HR was 66 bpm. After 3 minutes of reclining, the subjects BP increased to 121/71 mmHg and HR decreased to 62 bpm. The cause of this could have been student error or the subject may have been uncomfortable during the experiment. After reclining for 3 minutes, the subject immediately stood up It is hypothesized that their arterial pressure and heart rate will stay the same because the subject is not moving therefore blood is being pooled in the lower extremities and not getting back to the heart. This will cause a decrease in HR and BP. But the body will sense this and activate the SNS response to release norepinephrine to increase BP and HR or to get it back to what BP and HR was initially. After standing for 3 minutes, the subjects BP went from 129/70 mmHg to 121/75 mmHg and HR went from 86 bpm to 80 bpm. As stated previously, blood was starting to pool into the legs. The results do not necessarily support the hypothesis because there was a decrease in BP and HR. This could be because the SNS had not been activated just yet because the body did not sense a change in BP and/or HR. The body will sense a decrease in returned blood and will act upon it by increasing BP and HR to get more blood coming to the heart. After 3 minutes, BP decreased from 129/70 mmHg to 121/75 mmHg and HR decreased from 86 bpm to 80 bpm. The results showed a decrease in BP as well as HR. As stated in the hypothesis it was expected to

A decrease in peripheral systolic BP and AI was also observed. This finding suggests that an earlier return of the wave reflection from the periphery, a distinctive feature of stiffer arteries in hypertension, is associated with an increase in systolic BP. Therefore, the observed changes in AI may have occurred dependent of their effects on systolic

Cardiovascular system consists of the heart and it’s associated blood vessels. “Main functions of the cardiovascular system include the supply of oxygen and nutrients to all cellular tissues in the body while also removing metabolic wastes such as carbon dioxide” (Collins, 2013 p. 169). The heart is a four-chambered organ with two superior atria and two inferior ventricles. There is four valves located in the heart each function to prevent the backflow of blood into either atria or ventricular chambers. “The two valves located between the atria and ventricles are called atria-ventricular valves, while the two valves located between the pulmonary, aortic arteries and the ventricles are called semilunar valves” (Christensen & Kockrow, 2014 p.

Our blood pressure changes dependant on our posture. When we are standing up the heart has to work harder in order to pump blood around the body, this is because blood pools in our legs due to gravity. This means that our blood pressure is decreased. Less blood will now return to the heart this is called the venous return, which means that less blood is then pumped out of the heart called the stroke volume. Our heart rate is increased to ensure that sufficient blood travels around the body.

To modulate arterial blood pressure, which is a key factor in successful delivery of blood to tissues, the smooth muscles of the aorta and other arteries will either vasoconstrict or vasodilate in response to amount of blood flow based on nervous system controls (9). This mechanical adaptation is effective, because the blood flow is inversely proportional to fourth power of radius change in vessel and a slight change in vessel diameter will easily accommodate pressure difference in cardiac cycles. The blood flows in a pulsatile wave manner – a dicrotic notch corresponding to fall back of blood toward aortic valve is observed in aortic pressure immediately following the aortic valve closing – the degree of stress, whether it be a shear stress or an outward stress, is not uniform throughout the cardiac cycle (1, 11, 18). Adequate vasoconstriction or vasodilation can match vessel stress with the changing blood flow, and a laminar blood flow can be maintained despite of pulsatile blood flow especially in abdominal aorta, which has less natural turbulent flow that ascending and thoracic aorta may experience due to aortic arch

The heart is at the very centre of the cardiovascular system. It can be found on the left hand side of the chest and found beneath the sternum. Deoxygenated blood flows into the right side of the heart, it is then pumped to the lungs to pick up oxygen. The deoxygenated blood is then returned and is pumped around the body. The heart is surrounded by a thin layer called percidium. The cavity has a liquid that will prevent any sort of friction as the heart beats.

The average arterial pressure is reduced by just a small number of mmHg in a person when lying down compared to when the person is standing up. However, so that the average arterial pressure can be maintained, the individual who is standing in an upright position experiences an increase in sympathetic mediated or systematic vascular resistance, a decrease in the venous pressure because of the activation of the veins, a decrease in the stroke volume because of preload decrease, and a rate increase of the heart in the person (Klabunde, 2014). People who have autonomic nerve dysfunction are not able to utilize the compensatory mechanisms that their bodies and that result in displaying orthostatic hypotension in the person, and it is not the best thing for the body (Klabunde,

It is important to address the immediate factors among individuals that may affect the blood pressure measurement. The blood pressure of an individual fluctuates during the day, so it will be important to measure the blood pressure of each participant at the same time of day to prevent their normal body patterns from skewing data. If the cuff of the blood pressure monitor is too small for the participant, the systolic reading may be higher than the actual pressure of the subject. Blood pressure readings may also increase due to incorrect posture during measurement, such as when the back is not supported, both feet are not planted on the floor, and the upper arm is positioned incorrectly in relation to the heart; smoking, caffeine and alcohol intake, stress levels and

Orthostatic hypotension is defined as reduction of systolic blood pressure by at least 20mmHg and diastolic blood pressure by at least 10mmHg when changing the posture from supine to erect position. The ability to regulate blood pressure declines with age. It leads to a delay in blood pressure adjustment with posture among elderly people. As a result orthostatic hypotension is more common among elderly people. (Hajjar, 2005)

The cardiovascular system is the longest system of the body; consists of the heart, the major blood vessels that empty into or exit directly from the heart and a vascular network of smaller peripheral blood vessels (Ellis, 2013).

“…using anterior-to-posterior pressures (AP) of the cervical spine that resulted in a reduction in heart rate (HR),…”

The cardiovascular system is an intricate composition of muscle receptors, sensors and vessels such as capillaries, veins and arteries that work together allow blood to flow throughout the body with a normal pulse rate and pressure. However, the cardiovascular system must maintain and adjust to changes in posture, position and activity levels in the body. Blood flow can vary depending on the amount of energy one is exerting. For example, if one is resting the blood pressure, pulse pressure and rate will be different compared to one that just exercised. One way to measure the pressure of blood flowing in the body is through blood pressure. This is the “force exerted by blood against a unit area of blood vessel walls” (Marieb & Hoehn, 2014). The normal blood pressure measure for a human is 120/80 and this can be measured by systolic and diastolic pressures in the heart. The amount of blood that is being pushed out of your heart during ventricular constriction is called systolic pressure. When one listens to a heartbeat, this is the first heart sound they hear, also known as the “lub” sound. Systolic pressure is the highest pressure achieved during contraction and is responsible for sending blood out of the heart to where it needs to go. This is why the systolic pressure is higher than the diastolic pressure in a normal heart rate. The diastolic pressure is the pressure during ventricular relaxation. When one listens to a heart this is the second sound they

Each time the heart pumps, it sends blood all over the body to supply organs and tissues with oxygen and nutrients. The strength of the force created as the heart pumps blood into the vessels together with the vessels’ resistance to the blood flow is defined as the body’s blood pressure (Darovic, 2002). A normal range blood pressure (BP) must be between 100-130mmHg systolic (when the heart is beating) and 60-90mmHg diastolic pressure (between heart beats) (Sherwood, 1997). Many factors can change blood pressure, including exercise and diet. The regulation of BP within the body is tightly maintained by nerves, hormones and renal control in relation to three