1 2 the heart structure2

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Made of unique set of muscles called Cardiac muscle. They on contracting and relaxing without getting fatigue!


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Inferior vena cavacollects blood from lower part of body

Superior vena cavacollects blood from upper partshead, charms, neck

Right atriumreceives blood from the vena cava, less muscular

needs to send blood to ventricles Tricuspid valves- made up of three flaps hence known as atriove

valve separates ventricles and atria, allows blood to ventricles ontough tendinous cords (tendons or heartstrings)

Right Ventriclehas sufficient muscle to send blood to pulmona

through the semi lunar valve which prevent back flow enroute to Pulmonary artery brings blood back to left side of heart to left a

left ventricle through the bicuspid valve.

Left ventricle- exrts the most pressure as it contracts. Sends bloothe semi lunar vale to aorta


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Coronary Artery and veins supply the heart muscle with blooxygenate and nourish the tissues of the heart


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How the heart works The cardiac cycle :

Systolethe contraction of the heart can be divided into

Atrial systole - when atria contract together forcing blood in

ventricle Ventricular systolewhen ventricles contract . It happens 0

atrial systole

Diastoleor relaxationthe atrial fills with blood then one syone diastole makes a hearbeat. About 0.8s in humans this is

a cardiac cycle The electrical activity of the heart is know as ECG Electrocar


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Needs of the heart can make it beat fasterphysical exersice rai

oxygen needs of the body which inturn raises the heart beat to smuscles with oxygen for respiration

Permissible drugscaffeine or nicotine

Illegal drugs

The daphnia experiment

Intrinsic rhythmwhere the cardiac cells in an developing embryalready contracting and relaxing before the even form the actual h

The heart muscles, though can have triggers from outside, have thrhythm, and this reduced the bodys energy resourses in maintaini

heartbeat- The cardiovascular center in the brain responds to the variables

the blood, the receptors in the blood relay this information to thcardiovascular centre which in turn sends signals into the heart, enables the heart to respond to changes such as fear, sleep relax

- Hormones also affect the heart rate eg adrenaline


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Changing local blood pressure Constrictionand dilationis done through hormonesand ca

change blood pressure. Eg during exercise constriction can tin some arteries, causing them to have less blood flow and m

more blood flow to organs such as muscles that need the bl

However health conditions such asartheroscrelosis can caupermanent raise in blood pressure leading to health problem


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CVDs Cardiovascular diseases


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CVDs Cardiovascular diseases Most CVDs are related to artheroscrelosis (hardening of arte

buildup of yellow deposit of fat in the lumen. A plaque deporesult of damage of the endothelium starts and lipid depositwhich builds up

Hi h bl d d h i l i k d h l


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High blood pressure and chemicals in smoke can cause endotheldamage.

Leucocytes respond to the site due to inflammatory effect of damcause accumulation of chemicals and mostly fatty deposit whichas atheroma. Fibrous tissue and calcium also make it harden anelastic than it should be. This is artheroscrelosis.

This raises the blood pressure of the artery and it causes furtherelsewhere

Problems caused by artheroscrelosis and blood pressure

Aneurysm - severely weaken wall of artery due to plaque whichopen causing internal bleeding

Raised blood pressure can cause damage to tiny blood vessels ekidney where blood filters, protein may filter through the kidneytubules..kidney damage shows protein in urine

Bleedingin the brain causes a stroke

Damaged blood vessels in the retina causes blindness

ear sease


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ear sease Two main onesAnginaand Myocardial Infraction ( Heart

Anginaplaque build up slowly in the coronary artery,

First signs noticed esp during exercise where due to more demandthe narrowed arteries supply less blood to cardiac muscles which

respires anaerobically. Causing gripping pain in chest left arm and Helped by eating low fat diet more exercise and not smoking

Taking drugs to dilate the blood vessels

Heart Attackwhen a blood clot occurs in a coronary blood v

starving that patch of tissue. Artheroscrerosis takes place harblood vessel causing it to crack. Platelets are released makingwhich is called thrombosis

Symptomssevere chest pain last for several hours


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Strokean interaption of normal blood flowin the brain. Sodue to a clot that happens in the brain

Symptomsdizziness confusion slurred speech, blurred visparalysis when severe

If treated quickly a patient can survive the stroke and live lo

1 2 the heart structure2

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