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. CO 2 ) to pass in the other direction Vein - takes blood to the heart - have valves (to stop blood going backwards)
arteries veins 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 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 /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