A healthy heart

Heart Has 4 chambers - atria receive blood - ventricles pump blood out The muscle in the heart contract to

pump blood Right ventricle pumps blood to the

lungs Left ventricle pumps blood around the

body Valves inside the heart stops blood

flowing backwards Blood is carried away by blood vessels

Blood Vessels Artery - takes blood away from the heart - thick muscular wall Capillary - very thin (microscopic) - close to living cells and tissues - allow nutrients to pass across from

blood into the cells - allow wastes (e.g. CO2) to pass in

the other direction Vein - takes blood to the heart - have valves (to stop blood going

backwards)

arteriesveins

capillaries

Pulse The swell of an artery as blood is

pumped through - felt at neck, wrist, temples Pulse rate - the no. of heartbeats/minute - measured by a stopwatch - or pulsometer Resting pulse rate = average 60-

80 Increased by: - larger body mass - increasing age - gender (higher in females) - poor fitness

Fitness & the heart Fit people have a

lower pulse rate & recovery time

- heart & lungs are very efficient

- return to normal quickly after exercise

- this is recovery time

Blood pressure Heart muscle contracting

pumps blood This blood is under pressure - blood pressure High just after a contraction Low in between contractions Measured using a

stethoscope & mercury manometer

Or a digital sphygmomanometer

High/low blood pressure Caused by many factors: - being overweight - lack of exercise - fatty or salty diet - excessive alcohol - stress Effects of high blood pressure - angina (chest pains) - heart attack (blocked blood vessel in the heart) - stroke (blocked blood vessel in the brain) Low pressure is rare – causes fainting, linked to heart failure

Blood Made of 3 components: 1) Red Blood cells - tiny, disc shaped cells - approx 5 million cells/1ml of blood - carry oxygen 2) White blood cells - approx 5000-9000/1ml of blood - help fight infections (make antibodies) 3) Plasma - carries blood cells and dissolved

substances

Blood tests Allow for certain things in the

body to be monitored: - infection – increased no. of

antibodies - anaemia – low number of

red blood cells - diabetes – high blood sugar

level - leukaemia – very high no. of

white blood cells

Blood groups

Four possible blood groups

- A, B, AB, & O Blood transfusions

need to match blood types

If they don’t match, they can stick and clump together

- cause blockages in blood vessels

Testing for alcohol/drugs

Alcohol abuse leads to - mood swings, depression,

violence - inability to manage work and

family life Drunk drivers are responsible for

about 1000 deaths/yr in the UK - legal limit – 80mg/100ml blood - breathalysers/alcometers allow

blood alcohol to be examined - a saliva test can detect drugs in

the system