Date post: | 04-Jan-2016 |
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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)
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