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Hypertension, blood pressure, thermoregulation. STROKE VOLUME. The amount of blood pumped out of the left ventricle into the aorta with each beat of the heart. Measured in mL /beat An average person pumps about 70 mL of blood from their left ventricle with every heartbeat. HEART RATE.
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STROKE VOLUME • The amount of blood pumped out of the left ventricle into the aorta with each beat of the heart. • Measured in mL/beat • An average person pumps about 70 mL of blood from their left ventricle with every heartbeat.
HEART RATE • The number of times the heart beats per minute.
CARDIAC OUTPUT • The amount of blood that flows from the heart per minute. • Measured in litres per minute (L/min). • Can be calculated by multiplying the stroke volume by the heart rate.
BLOOD PRESSURE • Refers to the force exerted by circulating blood on the walls of blood vessels. • Measured in units of mmHg (millimeters of mercury) using a sphygmanometer. • Given in two numbers, for example 120/80
Systolic Pressure • The blood pressure when the left ventricle contracts, forcing blood into the aorta. • Top (or 1st) number in the blood pressure reading.
Diastolic Pressure • Blood pressure when the ventricles relax, and are exerting little pressure. • Bottom (or 2nd) number in the reading. • Typical, systolic pressure is higher than diastolic pressure.
HYPERTENSION (High B.P.) • High blood pressure causes the heart to work harder to pump blood around your body. • This can increase damage to your blood vessel walls.
THERMOREGULATION • Maintenance of body temperature within a range that enables cells to function properly. • In human beings, our temp. remains around 37°C
If you get too hot… • Your body will dissipate (or get rid of) heat. • Nerve impulses get sent to the hypothalamus which sends signals to sweat glands to initiate sweating. • Blood vessels on the surface of the skin dilate, losing heat to the skin.
If you get too cold… • Your body will conserve heat. • Hypothalamus sends signals telling blood vessels to constrict, limiting blood flow and retaining heat to the core of the body. • Nerve signals are sent to muscles telling them to start contracting rhythmically, generating heat….”shivering”.