unit 4

• Transport
• Temperature regulation
• Exchange of materials with body tissues
• Preventing infection 
• Blood clotting 

• SA Node- sends impulses to muscle fibres on oposite side- in the right atrium to the left 
• AV Node- catches impulses and delays them for a little while 
• Bundle of His- impulses sent down to the bundle of his then sent left and right to the purkinje fibres 
• Purkinje fibres- then make the right and left ventrical contract 

Two sets of nerves control the heart and allow it to prepare for danger 

• Parasympathetic branch- calms the heart and slows its pace 
• Sympathetic branch- speeds the pace & increases the strength of the beat is govened 

• Drainage and filteration 
• Removes excess fluid from the body tissue
• Absorbs fatty acids & transports them to the bloodstream 
• Produces white blood cells which produce anti-bodies (lymphocytes) 

• Blood plasma in capillaries- forced out through 'leaky' capillary walls 
• By hydrostatic pressue (pressue from heart pumping) 
• Fluid must return to circulatory system otherwise oedema occurs 
• Majority of fluid returns to capillaries 
• Remaining fluid (10%) drains into lymph vessel 
• This re-joins blood system near top of the body 

• Records the rhythm and electrical activity of the heart 
• electrodes connected onto legs, arms and chest - they are connected by wires to an ECG recording machine - picks up electrical signals that makes the heart beat- recorded and then printed onto paper- can detect when a heart beat is normal, too slow, too fast or irregular
• Resting ECG- individual is laying down in a comfortable position 
• Stress or exercise ECG- carried out when using an exercise bike or a treadmill. 
• Ambulatory ECG- Electrodes connected to a small portable machine worn at the waist so heart can be monitored at home for more than 1 day 

Factors increasing risk 

• Age
• Smoking
• High blood pressure 
• Obesity 
• diabetes
• Family history 

symptoms 

• Cold sweat- feel cold but are sweating because body is in crisist 
• Shortness of breath
• Light headedness/dissy

Treatments

depends when symptoms start 

•  12 hours- PCI, non-surgical used to treat the narrowing of the coronary arteries - coronary catheterization, insert of catheter. if unable medication- breakdown blood clots 

• 12+ hours- medication or bypass surgery- replace damaged arteries in heart muscle.

Diagnosis 

• ECG 
• Blood test
• Communicate- ask questions about how they are feeling 

Lifestyle changes 

• stop smoking 
• cut down alcohol intake 
• exercise regularly 
• stay at a healthy weight 

Monitor 

• routine ECG
• heart monitor 

Factors increasing risk 

• old age- heart muscle & cell wall
• Family history
• high salt intake- causes kidneys to retain water- increase blood volume- strain on heart 
• lack of exercise 
• obesity- more blood needs to be supplied with oxygen- more pressure to move blood around the body 
• smoking- raises blood pressure & heart rate, narrows arteries & hardens their walls 

Diagnosis

• Electrocardiogram- measures hearts electrical activity 
• blood pressure test
• urine test- see how other organs are working
• blood test
• cholesterol test

Monitor

• healthy adults aged over 40 - blood pressure checked at least once every 5 years 
• 24 hour monitor that checks blood pressure through out the day 

symptoms

• severe headache
• vision problems
• irregular heartbeat 
• blood in the urine 
• fatigue 

treatments 

• cutting salt intake 
• eating low-fat, balanced diet 
• being active 
• medication
• ACE inhibitors- reduce blood pressure by relaxing blood vessels 

Lifestyle changes 

• being active- resuces fatty buildup- less pressure around the blood vessles
• stop smoking
• drink less caffeine 
• getting at least 6 hours of sleep per night 

Symptoms

• Chest pain (angina) 
• Heart attacks
• Heart failure 
• Heart palpitations 
• unusual breathlessness 

Causes 

Hearts blood supply is blocked or interrupted by a build-up of fatty substances in coronary arteries. This can be caused by:

• smoking
• high cholesterol
• high blood pressue
• diabetes 

Diagnosing 

• blood tests
• doctor asking about medical, lifestyle and family history 
• treadmill test 
• CT scan 
• MRI scan

Treatments

It cannot be cured- help to manage the symptoms and reduce chances of problems, heart attack

• lifestyle changes- regular exercise & stop smoking 
• medication 
• angioplasty, balloons & stents used to narrow heart arteries 
• surgery 

Lifestyle changes

• Eating healthy, balanced diet
• physically active
• giving up smoking
• controlling blood cholesterol and sugar levels