The Cardiovascular System

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The Cardiovascular System by Mind Map: The Cardiovascular  System

1. Three main blood vessels

1.1. Arteries

1.1.1. Tunica Adventitia outer layer, made of connective tissue fibres which reinforce the walls of the vessels which allows it to withstand high pressure.

1.1.2. Tunica Media Middle layer made up of smooth muscle cells and is thicker in arteries than in veins.

1.1.3. Tunica Intima Single layer of cells which lines the entire cardiovascular system.

1.2. Capillaries

1.2.1. Capilary bed Network of capillaries supplying an organ. The more metabolically active the cells. The more capillaries it requires to support nutrients.

1.3. Veins

2. Pulmonary, System, Heptic portal + Foetal circulation

2.1. The pulmonary circuit carries blood to the lungs to be oxygenated and back up the heart.

2.1.1. In the lungs C02 is removed from the blood and the oxygen is taken up by the haemoglobin in red blood cells

2.2. The systemic circuit carries blood around the body to deliver oxygen and returns the de-oxygenated blood to the heart.

2.3. The Heptic portal circuit takes nutrients in the blood from the digestive system back to the heart via the liver.

2.4. Foetal circulation - the circulation of blood before and after birth can differ cause the foetal have to receive oxygen and nutrients from matural blood instead of from its own lungs and digestive system.

2.4.1. Specialised blod vessels carry the foetal blood to the placentae where exchange occurs and then returns to the foetal body.

2.4.2. Ductus Venosus is another structure that allows blood to bypass the immature foetal liver and empty directly into the infra vena cava.

3. The Heart

3.1. Chambers of the heart

3.1.1. Atria 2 thin walled chambers that receive blood from the veins,

3.1.2. Ventricles 2 are thicked walled chambers that forcefully pump blood out of the heart. The wall of the left ventricle is thicker than the right because it pumps blood to the entire body.

3.2. A muscular organ located between the lungs in the medicatinum.

3.3. Protection of the heart

3.3.1. surround by protective cage ribs

3.3.2. located posterior to the serum

3.3.3. Anterior to the thoracic spine

3.4. The bottom tip of the heart is turned to the left so that about 2/3 of the heart is on the body left side.

3.5. Layers of the heart

3.5.1. Pericrdium

3.5.2. Myycardium

3.5.3. Endocardium

3.6. The top of the heart (base of the heart) connects to the great blood vessels.

3.7. Heart Valves

3.7.1. 2 types of valves that keep blood flowing in the correct direction.

3.7.2. The valves between the atria and ventricle are called atrioventricular valves (AV)

3.7.3. Pulmunary urtery are called semilunar valves.

3.7.4. The left AV valve is biscupid valve and the right AV valve is the tricuspid valve.

3.7.5. The action of papillary muscles and the chord thendinae open the valves and keep the valve flaps in place as the chambers contract.

3.8. Heart sounds - closure of the valves produce rhythmical and repetitive sounds that are described as LUB DUB.

3.9. Coronary circulation

3.9.1. Blood is supplied to the heart by its own vascular system.

4. The Cardiac Cycle

4.1. Takes 0.8 seconds.

4.1.1. Distole - the filling phase takes 0.5 seconds

4.1.2. Systole - the contracting phase takes 0.3 seconds.

4.2. Blood pressure within the chambers FALLS. blood then starts to back flow as there is no push away at this point.

4.2.1. The back flow is not allowed to go to far and not allowed to re-enter the heart - as the blood tries to back flow in pushes the semilunar valves closed blocking any further entrance to the heart. During this phase all heart valves are shut.

4.2.2. At the end of the ventricles they have expanded so much that the pressure inside the ventricle has dropped. Meanwhile the atria have started filling

4.2.3. Once the pressure within in the ventricles is less than the pressure within the atria this is encourage to cause the opening of the atria-ventricular valve and ventricular filling begins.

4.2.4. Blood enters the heart via the vents Cavan and pulmonary veins

4.2.5. Atrial contraction occurs during the last phase of ventricular filling and this forces the last 25-30ml out of atria into the ventures beneath them.

4.2.6. As soon as the ventricles are full this causes all valves to shut. Pressure builds up and the ventricles as they prepare to contract.