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

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”.