How Different Conditions Affect Blood Pressure And Pulse Rate

Introduction:

The general purpose of this experiment was to see how different conditions affected blood pressure and pulse rate. Blood pressure is defined as the force exerted on a vessel wall, and is expressed in millimeters of mercury (mmHg) (Marieb). Systolic pressure is the pressure in an artery at the peak of ventricular systole, or contraction, where blood is being ejected out of the artery. Diastolic pressure is the pressure in an artery at the end of ventricular diastole, when blood fills the chamber. Systolic pressure averages 120mmHg, whereas diastolic pressure averages 80mmHg (Class Materials). Mean arterial pressure (MAP) is the average pressure exerted by blood on the walls of arteries, and it is also an important factor to consider

It was hypothesized that blood pressure would decrease after reclining because your body is in a less stressful state at the time. The body does not have to fight against gravity to push blood to the brain because the blood is able to flow more easily (Callahan). The pulse rate is expected to stay the same because the body isn’t doing any extraneous movement. Because the body is essentially at rest, the Parasympathetic Nervous System is at work in order to save energy in the body. Immediately after standing, it is hypothesized that blood pressure would increase because of the sudden change in blood volume that is being distributed to the legs. Baroreceptors are blood pressure receptors in the carotid sinuses and in the aortic arch that are activated when arterial blood pressure rises (Marieb). In this case, the baroreceptors will be stimulated, the cardioinhibitory center (CIC) will be stimulated, and the vasomotor center will be inhibited. This will then cause a decrease in the sympathetic impulses to the heart, which would then decrease heart rate and decrease cardiac output (Class Materials). This mechanism is known as homoeostasis. Heart rate is also expected to increase after quickly standing because the body’s nervous system isn’t adjusting properly to a different body

It was hypothesized that cognitive stressors would increase heart rate and blood pressure. When our bodies are faced with stress, such as spelling words backwards and forwards, they respond by releasing stress hormones into the blood that arrange the body for the “fight or flight responses”, and initiate the sympathetic nervous system (SNS). The SNS releases epinephrine and norepinephrine which causes vasoconstriction. Vasoconstriction of the blood vessels happens in order to distribute more blood throughout our entire body rather than just the extremities and it causes an increase in mean arterial pressure