Homeostasis of BP and Heart Rate
A normal blood pressure can be identified by having a systolic pressure of around 120 and a diastolic pressure of around 80. This value is expressed as "120/80". A normal heart rate is expressed as the amount of times it beats in a minute; a normal adult heart rate is between 60-100 beats per minute (BPM). There is a relation between these two measurements, but they are stimulated by several different circumstances.
The blood pressure is mainly affected by the decrease in blood volume; the body reacts and maintains homeostasis by initiating either long term or short term processes. The short term process has a direct effect on heart rate, which is sympathetic activation, increasing heart rate, which in turn increases blood pressure. The long term process is increasing blood volume by production of more erythrocytes or the retention of liquid. The liquid is maintained whether it is by activating thirst in order to cause the intake of liquid, release of antidiuretic hormone (retaining liquids), or aldosterone secretion. All three of these liquid maintenance processes are activated by Renin.
The heart rate is affected by body temperature, fitness level of person, age, sex, caffeine intake, and exercise. The increase or decrease in heart rate has many uses. Athletic people will have lower resting rates because perfusion is more efficient in athletic people. The temperature whether it increases above or decreases below normal values will cause the HR to increase or decrease respectively. Normally a person perspires to cool off. This causes him to lose fluid and become dehydrated. As a result, the body has to come up with another way to cool off, so the blood vessels dilate. This lowers the pressure within the veins, allowing the blood to cool. Caffeine is a stimulant and causes increased HR, and when a person exercises, their heart rate increases. All of this is to meet the body’s metabolic needs, producing adequate...
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