The Circulatory System Theory

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Underlying theory:
• Circulatory system theory:
It is the body’s main transport system, the system is made up of the heart, the blood and the blood vessels. The blood transports oxygen, carbon dioxide, hormones and nutrients, . The circulatory system is a closed system which means that blood flows around the body enclosed in blood vessels and does not leave the blood vessels. The heart:
The heart consists of many layers:
1. The pericardium- It has two layers.
(i) An outer layer which contains a fibrous covering that wraps around the heart and holds it in place.
(ii) An inner layer which has special fluid to lubricate the heart preventing friction from occurring.

2. The myocardium- this contains a strong layer of cardiac muscle
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It also has a very thick cardiac muscle wall (myocardium), this is because it needs a strong wall to be able to push the oxygenated blood to all areas of the body.
The heart also contains
(i) The tricuspid and bicuspid valves- these are situated between the atrium and ventricle. It is there to prevent backflow of blood from the ventricle to the atrium, it is a one way flow of blood.
(ii) The septum- this divides the right and left sides of the heart.
(iii) Pacemaker- this sends out regular nervous impulses which travel along the axons of the pf the nerve cells out through the walls of the atria. It is located at the top right of the atrium.
(iv) Semi-lunar valves- these prevent the backflow of blood into the heart
(v) Superior vena cava- this brings deoxygenated blood from the upper part of the body to the heart
(vi) Inferior vena cava- brings deoxygenated blood from the lower part of the body to the heart
(vii) Pulmonary artery- transports deoxygenated blood away from the right side of the heart to the lungs
(viii) Pulmonary vein- this is where oxygenated blood leaves the lungs and returns to the heart
(ix) Aorta- passes blood from the left ventricle to the whole body

The blood
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It occurs when the flow of blood to the heart is blocked, there is a number of things that can cause this to occur’ (heart attack, 2017)

• Bad cholesterol
• High blood pressure ( this can damage arteries)
• High intake of trans and saturated fats
• Smoking
• If family in the past have had history with heart attacks you may be at risk
• Obesity
• Stress
• Illegal drug use (such as cocaine )
• Lack of physical activity
• Age (men age 45+ and woman 55+ are more at risk of having a heart attack )
• Cold sweat
• Fatigue
• Tightness in the chest or arms
• Struggling to breath
• Dizziness

 Atherosclerosis Definition:
This is also known as high cholesterol. It occurs when the blood flow from blood vessels become restricted, the vessels themselves become thick and stiff.

• High cholesterol
• High blood pressure
• Inflammation from diseases such as arthritis
• Obesity
• Family history of high cholesterol
• Lack of exercise
• Unhealthy

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