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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