In a nutshell, this week in lab we performed three experiments; each dealing with variables effecting heart rate. Our three variables were cold, heat and exercise. The results of the lab confirm cold slows down the heart rate (and everything else in the body) in order to conserve body. Blood is redirected from the outer limbs to the inner core to keep the vital organs functioning at maximum efficiency.
Heat speeds up the heart rate. The heart beats faster in an attempt to dissipate heat through convection on the surface of the skin. Sweating facilitates this process.
Exericse also inceaseses the heart rate. As it does so to deliver more oxygen to the tissues blood pressue should incease. However, in actuality we notice that blood pressure will remain constant if not decrease a little. This is due to dilation of the blood vessels in response to the increase in stroke volume (dt increase heart rate).
If the body is unable to adjust and regulate the internal body temperature injuries will occur. These include hypothermina, chilblain, immersion foot, heat stroke and heat exhaustion. High blood pressure for extensive amounts of time will cause damage to the arteries as well as damage to the heart.
EKG: an electrocardiogram which measures electrical activity of the heart. It is characterized by a PQRST wave which identifies contractions of the ventricles, arteries and resting (the heart refilling with blood).
Pulse is the palpated throbbing of the arteries from the pumping of oxygenated blood from the left ventricle. Average pulse for a healthy adult is between 60-100 bpm (beats per mintute). Tachycardia is the term for pulse faster than 100 bpm. Bradycardia is defined as the a heart rate lower than 60 bpm.
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