risk factors for cardiovascular disease (2)

high blood pressure known as hypertension is considered to be one of the most common factors in the development of CVD.

this is because high blood pressure increases the chances of atherosclerosis occuring.

blood pressure is a measure of the hypostatic force of the blood against the walls of a blood vessel. blood pressure is higher in arteries and capillaries than in veins.

pressure in the artery is highest during the cardiac cycle when the ventricles have contracted and forced blood into the arteries. this is systolic pressure.

pressure is lowest in the artery when the ventricles are relaxed. this is the diastolic pressure.

A sphygmomanometer is used to measure blood pressure.

it involves an inflatable cuff that is wrapped around the upper arm, and a manometer that measures pressure.

when the cuff inflates the blood in the artery in the upper arm stops flowing. then as the cuff slowly deflates the blood starts to flow through again, the flow of blood can be heard using a stethoscope positions on the artery below the cuff.

a pressure reading is taken when the blood first starts to spurt through the artery that has been closed. this is the systolic pressure.

A seocnd reading is taken when the pressure falls to the point where no sound can be heard in the artery, this is diastolic pressure.

units are kilopascals, but medical practises like to use millimeters of mercury.

blood pressure is reported as two numbers, one over the other.( 140/85 )

the top number (140) means the systolic pressure and the bottom (85)  is the diastolic pressure.

for a healthy person you would expect a systolic pressure of 100-140mmHg, and a diastolic pressure of 60-90mmHg.

contact between the blood and walls causes friction which impedes the flow of blood. this is called peripheral resistance.

the arterioles and capilleries offer a greater total surface area, resisting flow more, slowing the blood down causing the blood pressure to fall.

if the smooth muscles in an artery of arteriole contract, the vessels constrict, increasing resistance which in turn raises the blood pressure.

when the smooth muscle relaxes, the lumen is dilated, so periphiral resistance is reduced and blood pressure falls.

any factor that causes arteries and arterioles to constrict can increase blood pressure, some factors include natral loss of elasticity with age.

one sign of high blood pressure is oedema, fluid building up in tissues and causing swelling.

at the arterial end of a capillary, blood is under pressure. this forces fluid and small molecules normally found in plasma out through capillary walls into the intercellular spaces , forming tissue fluid. the capillary walls prevent blood cells and larger plasma proteins from passing through, so these stay inside the capillaries.

is blood pressure rises above normal, more fluid may be forces out of the capillaries, in such circumstances , fluid accumulates within tissues causing oedema.

Age and gender have an affect of the risk of CVD.

with age the arteries become less elastic and can be more easily damaged/