The Heart.

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Function

Deoxygenated blood from the body is pumped through the right atrium and the right ventricle to the lungs where it is oxygenated. Then pumped through the left atrium and ventricle round the body.

The triscuspid valve seperates the right atrium from the left ventricle.

The pulmonary valve seperates the right ventricle rom the pulmonary artery.

Bicuspid valve seperates the left atrium from the left ventricle.

Aortic valve seperates the right ventricle from the ascending aorta.

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Purpose

The purpose is to pump blood and deliver oxygen and nutrients to body cells.

It is divided into four compartments- Atria and Ventricles.

The circulatory system is a network of veins and arteries.

Arteriwes, aterioles and capillaries carry oxygenated blood.

Veins and venules carry deoxygenated blood back to the heart.

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Pacemaker

The heart contractions arise from the hearts natural pacemaker, the sino-artial node.

This is located in the right atrium and sends out electrical impulses causing the atria to contract and pump blood into the bottom chambers (ventricles).

The electrical impulses pass to the ventricles through the atrio-ventricular node. Which spreads into the ventricles causing the muscle to contract and pump blood to the lungs and body.

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Arteries & Arterioles

Arteries

Structure- The walls of the arteries are a smooth muscular wall that contracts and relaxes under the instructions of the sympathetic nervous system.

Function- Carry blood away from the heart, only oxygenated (except. Pulmonary artery)

Arterioles

Structure- Tiny branches of arteries that lead to capillaries. Also under the control of the sympathetic nervous system. Construct and dilate to regulate blood flow

Function- To transport blood from arteries to capillaries. They are also the main regulators of blood flow and pressure.

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Capillaries

Structure:

Tiny blood vessels supplied with blood by the arterioles and drained by venules. Walls are one cell thick which allows the exchange of material from the surrounding tissue.

Function:

Supply tissues with essential componments carried by the blood. Remove waste from surrounding cells. An exchange of oxygen, Co2, water and salt between the surrounding tissues.

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Veins & Venules

Veins

Structure- Walls consist of layers of tissues that are thinner and less elastic than the corresponding layers of arteries. Include valves which aid the return of blood to the heart by preventing backflow.

Function- Transport blood towards the heart. Deoxygenated blood only (except. Pulmonary vein)

Venules

Structure- Minute vessels that drain blood from capillaries and into veins. Unite to orm a vein.

Function- To dtrain blood from capillaries into veins for return to the heart.

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Dysfunctions [1/2]

Changes in blood pressure. Contracts=Systollic. Relaxes=Dystollic

Coronary Heart Disease, narrowing or blockage by a gradual build up of plaque resulting in a M.I

Heart attacks also known as a coronary. This is death of an area of tissue because of interrupted blood supply.

M.I= Myocardial Infarction

Aneurysm is a sac which develops in a wall of an atery or vein of the aorta having the highest incidence.

Pericarditis is the inflamation of the pericaridum, the pericardial layers bind and stick together and form painful adhesions which interfers with the hearts movement.

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Dysfunctions [2/2]

Ischaemia is the lack of blood supply to the heart.

Atheroscierosis is the hardening of the fatty tissues in the walls of the medium and large arteries. Factors are high blood pressure, smoking and high cholesterol levels.

Agins pectoris is when the myocardium does not recieve sufficient blood supply and is deprived of ocygen. This leads to the death of cells and eventually form an infarct.

Infarct= death of tissue.

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Diagnostic Tests [1/2]

Signs & Symptoms= Chronic chest pains, high blood pressure, cold and clammy skin.

Diagnostic Tests

Blood tests- show raised enyzmes that are released into the blood (only in heart cells)

Imaging xrays- Shows the outline and shape

Blood pressure monitoring

Electrocardiogram- Electrical recording of the heart

Angiogram- A dye that absorts x-rays, injected into blood and locates the blockage.

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Diagnostic Tests [2/2]

Monitoring blood pressure to check for hypertension

Cardiac catherisation- A catheter is inserted through a needle into the femoral artery through a small incision on the groin. Direct to the heart using an x-ray screening monitor as a guide. Measures pressures within each chamber in the arteries. Blood samples can be taken to check oxygen levels.

Electrocardiogram- Measures electrical activity of the heart. The signals come from the sino-artial node. the natural pace maker of the heart. Records any problems with the hearts rhythmn and electrical impulses.

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PQRST Waves [1/2]

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P= Caused by the impulsor of contraction which sweeps over the atria.

QRS= Wave is indictative of the spread of impulse of contraction from the atrioventricular node.

T= Represents the relaxation of the ventricular muscle.

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PQRST Waves [2/2]

Principle and Values

Doctor can examine the patients waves and the time intervals between them to measure the state of muscle and the conducting system (myocardial) within the heart.

Blood pressure

Defined as the fource or the pressure which the blood exerts on the walls of the blood vessels in which it is contained.

When the left atria contracts and pushes blood into the aorta the pressure produced is known as the systolic 120 mmHg.

When the heart is resting it is known as the dystollic 80mmHg.

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Diagnostic Tests Cont.

Electrodiagram: Made up of three waves, P, QRS, T. Reveals rhythmn problems, demonstrates thickening of a heart muscle.

Heart bypass: Coronary artery bypass graft (CAGB). Reroutes the blood flow around the obstructed part of the atery. uses a portion of a blood vessel taken from a nother part of the body. One end is attached by the side of the blocked atery and the other end is attached directly to the aorta. Blockage is bypassed and blood supply is restored.

Pace Maker: Simulates the heart into beating at an appropraite rate. Can sense if the heart rate changes to maintain the correct pace of beat. Matching the doner with use of drugs called immuno-suppressants which reduces the chance of rejection. They then have to take drugs for the rest of their life.

Risk factors of coronory heart disease- Being male, family history, smoking, high alcohol intake, farry diet, high blood pressure, obesity and inactivity.

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Effects of smoking [1/2]

Hair loss, ear glue, headache, paralysis, panic attacks, gum disease, thickening and toughening of artery walls, osteoporosis, bronchitis, impotence, miscarriage, testicular cancer, cervical cancer, cellulite, cataracts, loss of smell, stroke, loss of speach, bad breath, tooth loss, gangrene, stomach ulsers, deformed sperm, reduced sperm, cot death, wrinkles, grey parch, reduced oxygen supply to the brain, nicotine hangovers, mood changes, sore throat, cancer in lips and throat, periphal vascular diease, bladder cancer, kidney cancer, pancreas cancer, stomach cancer, low birth rate, ageing and slow healing.

Mouth, throat, larynx: Cancer, inflamation and laryngitis.

Respiratory system: Bronchitis, emphysema and lung cancer.

Circulatory system: Heart disease, heart attack, high blood pressure and coronary heart disease.

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Effects of smoking [2/2]

Bones: Osteoporosis

Immune system: Depressed responses, increased infections

Pregnancy and babies: lower than avergage birth rates, sudden infant death syndrome, premature birth, miscarriage and still birth, impairments in mental and physical growth

Brain: Brain haemorrhage, stroke, women on contraception=more chance of stroke

Stomach and intestines: cancer, ulsers, tender, bleeding.

Pancreas, bladder and kidneys: cancer

reproductive system: decreased sperm count, low sex drive, egg damage, irregular menustral cycle, breast, testical, cervix and **** cancer, early menopause and altered hormone levels.

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Effects of smoking [2/2]

Bones: Osteoporosis

Immune system: Depressed responses, increased infections

Pregnancy and babies: lower than avergage birth rates, sudden infant death syndrome, premature birth, miscarriage and still birth, impairments in mental and physical growth

Brain: Brain haemorrhage, stroke, women on contraception=more chance of stroke

Stomach and intestines: cancer, ulsers, tender, bleeding.

Pancreas, bladder and kidneys: cancer

reproductive system: decreased sperm count, low sex drive, egg damage, irregular menustral cycle, breast, testical, cervix and **** cancer, early menopause and altered hormone levels.

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