The Relationship Between Diet, Blood Pressure, Blood Cholesterol and Circulatory Disease

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5.2 Discuss The Relationship Between Diet, Blood Pressure,
Blood Cholesterol and Circulatory Disease
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Having a poor diet can result in you developing high blood pressure and high cholesterol levels, this is due to the build up of fat and waste in the arteries causing clotting and blockages. When our diet consist of a lot of high saturated fats it leads us to have high cholesterol because our body systems all link together. When we have a high cholesterol level it causes a rise in our blood pressure, this is because our heart is having to work harder to try and circulate the blood around effectively even though our arteries are becoming blocked due to the build up of fats. Has our blood pressure gets higher this also puts pressure on the blood vessels causing them to narrow which restricts the normal flow of blood and increases the pressure. When the pressure of the blood flow is increased it puts strain on the heart which could then lead to damaging the heart by way of a heart attack, high blood pressure can also cause a stroke and overall cause circulatory disease. Having high blood cholesterol which is linked to a poor diet can also damage the artery walls because it makes them more vulnerable to having fatty acids attach to them that are floating around which causes atheroma, again linked to circulatory disease.

Overall when people say you are what you eat is true in the case of your arteries, if you eat a lot of fatty food then that is what your arteries become blocked up with the fat and build up of plaque and calcium, that eventually could break away causing serious health issues.

Changes In Artery Structure Associated With Circulatory Disease

5.1 Describe The Changes In Artery Structure Associated With Circulatory Disease
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This blog is going to look at how the artery structure is effected due to circulatory disease. Circulatory disease begins when there is a malfunction of special cells that line the arteries.The cells are called endothelial cells and they are the key to atherosclerosis and it is the under laying cause of the dysfunction of endothelial. At the beginning of artherosclerosis there is inflammation and immune cell activation at the endothelial level, this then causes the malfunction of the endothelial and damage is then eventually caused to the artery and there is a build up of plaque.
Our arteries have three layers, the outside layer is mainly connective tissue and it gives the structure to support the under layers. The middle layer is smooth muscle, this contracts and dilates which allows the control of the blood flow and to maintain blood pressure. The inner layer is a thin layer of endothelial cells and this provides a smooth, protective surface. The endothelial cells prevent toxic, blood borne substances from getting to the smooth muscle of the artery. The cells also help to respond to a change in blood pressure and they release a substance into the cells of the smooth muscle that help change the muscle tone of the artery. They also secrete chemicals, these chemicals create a protective response in the artery for when there is an injury, one of the messages is sending a signal to the smooth muscle cells and white blood cells to gather around a site where injury may be.
As we get older the endothelium gets leaky, this lets lipids and toxins out and they break through the endothelial layer and enter the smooth muscle cells. The smooth muscle cells then build up where the artery is damaged and the artery then looses some of it's flexibility. The white blood cells are then signalled by the endothelium and they gather along the cell wall, the white blood cells then produce pro - inflammatory substances such as leukotrienes and prostaglandins, they also damage free radicals that attack the endothelium. Has this is happening toxins start to break through into the arterial wall and lipids like ldl, cholesterol and triglycerides gather and become oxidized.
Once the oxidized process has begun the body then starts to try and build up a immune response, this causes the white blood cells to attack the fats which then causes more inflammation in the arterial wall. The smooth muscle cells then try and build up a collagen this is to form a cap over the damaged area, however the mixture of the white blood cells, smooth muscle cells and the lipids that are oxidized create a plaque deposit. The plaque deposit then over time forms a build up of calcium that accumulates on it which then creates a brittle cap. The brittle cap could then rupture which could result in the formation of a blood clot, which could then lead to a heart attack or stroke, or could even effect the lungs. However there is also the possibility that the blood clot stays where it is and doesn't cause a problem.
There is also artheroselerosis, which is a build up of fatty tissue, this causes the artery wall which is normally smooth with no friction to be rough and also to build up with plaque. This is caused by high blood pressure and as the the plaque builds up the lumen decreases causing the blood pressure to raise even more.
The reason blood clots occur or people have heart attacks or strokes is because there is a lack of blood flow and oxygen to the heart because the arteries are blocked due to circulatory disease, which is causing the build up of plaque.
Overall we can do things to try and prevent ourselves getting circulatory disease and that is to try and lead a sensible healthy lifestyle. Smoking and a high cholesterol diet are a big factor in the disease along with high blood pressure, all of which can be controlled if we want to make changes for the good of ourselves.

The Process For Redistributing Blood During Exercise

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4.2 Explain The Processes For Redistributing
Blood During Exercise
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This blog is looking at how blood redistributes during exercise, during exercise our blood flow increases due to the increase in the heart rate. When at rest the blood flow to our muscles is only around 20 -25% but during exercise that increases to around 80 - 85% (biosbcc.net). The increase in the blood flow to our skeletal muscles is iniciated by three things, an increase in our cardiac output, vasodilation of skeletal muscle arterioles and vasoconstriction of arterioles in the viscera and skin.
The increase in our cardiac output is caused by the sympathetic nervous system, the increase in this causes the heart rate and stroke volume to increase. During exercise the increase venous return of blood to the heart this is done by way of the skeletal muscle pump and also by the respiratory pump. When there is an increase in the venous return it leads to an increase in end diastolic volume, which then causes the stroke volume to be increased.
The most important factor of the flow of blood being monitored correctly during exercise is local metabolic control, this is vasodilation of the skeletol muscle arterioles. During exercise the muscle activity increases which causes the build up of metabolites and that then induces the vasodilation of the local arterioles. As well as this the beta adrenergic stimulation by epinephrine causes vasodilation of arterioles in the skeletal muscles.
Leading from the alpha adrenergic sympathetic stimulation, arterioles in the viscera and skin vasocnstrict during exercise, this is vasoconstriction of arterioles in the viscera and skin. During exercise our body temperature rises, cutaneus arterioles dilate in order to radiate heat and reduce body temperature.
So overall during exercise our heart rate increases causing the blood flow to increase and rise towards the skin, the increase of blood flow also allows more blood to go towards the skeletal muscles due to them working harder and needing the energy produced to allow them to work correctly and effectively.

Mechanisms For Regulating Ventilation and Pulse Rates

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4.1 Explain The Mechanisms For Regulating Ventilation
and Pulse Rates
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This blog is discussing what is needed to regulate ventilation and pulse rates, it is a result of homeostasis of the cardiovascular system. Our heart rate can be increased due to the amount of adrenalin that is in the blood stream, it can also be increased from the nerves from the sympathetic nervous systems. This can also increase the stroke volume, the nerves are stimulated by an increase in the carbon dioxide levels in the blood stream. The rise in the level of carbon dioxide comes from the increased release of oxygen in the cells, the way in which this occurs is as follows. There is an increase of the CO2 levels in the blood stream, this is then picked up on by the chemoreceptrs on the cartoid body. The chemoreceptors then send impulses to the cardiac acceleratory centre, this is in the medulla part of the brain. From here the cardiac acceleratory centre then sends impulses by way of the sympathetic nervous system to the sino atrial node in the heart, this is the accelerator. This then causes the release of the hormone noradrenline at the sino atrial node, this is what makes the heart beat faster.
Our cardiac output can also decrease, this is done by nerves from the parasympathetic nervous system. The nervous are stimulated due to a fall in the level of carbon dioxide. This happens as follows, the level of CO2 drops in the blood stream, this is noted by the chemoreceptors that then send impulses to the cardiac inhibitory centre in the medulla. From there impulses are sent by way of the parasympathetic nervous system to the sino atrial node in the heart. This then results in the impulses releasing the hormone aceytlcholine at the sino atrial node, this hormone then decreases the heart beat and stroke volume.
The higher the CO2 in our body the more we breath in, but the lower the CO2 in the blood stream the less we breath in. We breath in more when we exercise because this is what increases our CO2 levels and we breath less when we are asleep because we are at rest and our CO2 levels are lower.
Overall if we have a high concentration level of CO2 levels in our system we breath in a lot more which increases our heart rate which could put to much pressure on our heart if it regularly happens, but if carried out as a regular but sensible programme then it can help strengthen the heart and help with our respiratory system, decreasing the risk of heart problems, strokes and respiratory problems.

Cardiac Output and Importance Of Value

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3.4 Calculate Cardiac Output and Discuss The
Importance Of Value
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This blog is looking at how to measure our cardio output and the importance of measuring it. Our cardiac output is the measurement of how much blood is pumped by each ventricle per minute, this can be measured by the formula cardiac output = stroke volume x heart rate. By using this formula I measured my cardiac output and the results were 80 x 70 = 5600 cm3 = 5.60 litres per minute.
At rest the normal rate of blood is 5 litres per minute, but during exercise it can be up to 30 litres per minute. Our cardiac output depends on how much blood is getting back to the right hand side of the heart, this is known as venous return. When our blood return increases due to exercise this is because of the myocardium contracting stronger, causing the stimulus that the muscle fibres to stretch.
If our heart rate is low it can cause to feel unwell and also give us indication that there isn't enough oxygen getting around the body. Some things we could end up with are low blood pressure, fainting spells, dizziness, feeling tired and sluggish, not getting enough nutrients into our body causing mal - nutrition and also we won't be able to get rid of the carbon dioxide out of our body which can cause us severe problems with our heart, lungs, respiratory system and all other parts of the body.
Another issue that could be picked up from measuring our cardiac output is if we have high blood pressure, are at risk of a stroke or a heart attack, it could also indicate if we are under stress or even just been exercising.
Overall measuring our cardiac output is important for many reasons and could prevent us from serious health problems or even death, so it is worth just having it taken every so often to ensure that things are alright because even though you think they are it isn't always he case, and as they say prevention is better than the cure.

The Electrical Activity Of The Heart

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3.3 Explain The Electrical Activity Of The
Heart During A Heart Beat
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Our heart as a pace maker of it's own and this is what helps keep our heart beating at a regular rate. The natural pace maker is situated in the upper part of the right atrium and it is a group of specialised electrical cells known as the Sinus or Sino - Atrial node.
The electrical system Carry's sparks that stimulate the muscle wall of the four chambers of the heart, those being the left atrium, right atrium, left ventricle and right ventricle to contract and then empty, this is done in a certain sequence. The first parts of the heart to be stimulated is the upper parts and the atria, after this there is a small delay which allows the two atria to empty, then the two ventricles are stimulated.
For the stimulation to happen adrenaline needs to be built up causing the sinus node to increase the amount of sparks per minute, this then increases the heart rate, how much adrenaline is released is determined by our nervous system. Our heart beats on average 72 times a minute (heartsite web) and when we carry out exercise or are stressed then the sinus node speeds up, this also occurs when our body needs an extra boost of blood supply.
The way in which the electrical activity takes place in the heart is as follows. When the sino - atrial node fires the electrical impulse goes through both the left and right atrium, this then causes both chambers to contract. When this happens this activity on an ECG would be known as the 'P' wave. From here the impulse then goes to the atrio- ventricular node which is just above the ventricules, it is then held here shortly. The reason it is help is to allow the left and right atrium to carry on emptying there blood into the ventricles, on an ECG this would then show as the 'PR interval'. The atrio - ventricular node is then acting as a rest area which is delaying the stimulation of the ventricles whilst the two atria empty. Once the delay is over the impulse then travels through both the ventricles, this then causes them to contract and blood is then sent into the pulmonary artery and the aorta, this is shown as the 'QRS complex' on an ECG. Once the ventricles have then recovered from the impulse it generates an 'ST segment' and T wave on an ECG.
The thing that makes the heart make the 'Lub' sound is when the impulses are in the ventricular systole stage and the pressure of the blood is causing the ventricular valves to close, the valve is opened during atrial systole and when it makes the 'Dub' sound it is during the diastole stage and due to the pressure of the blood being so high in the arteries that it causes the semi lunar valve to shut, the semi - lunar opens during ventricular systole.
Overall again our heart with help from our nervous system is playing a major part in our body and it enables us to breath without having to think about doing it.

The Heart Structure and The Cardiac Cycle

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3.2 Describe The Structure Of The Heart and Explain
The Cardiac Cycle
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This blog is going to discuss the structure of the heart and look at how the cardiac cycle works.In an adult our heart beats around 70 times a minute which on average is 100,000 beats a day and on average it pumps 100 millilitres of blood per beat around the body (biology reference web).
Our heart sits on the left centre of the chest and it is a lubricated sac known has the pericardium, and it consist of four chambers, the left ventricle, right ventricle, left atrium and the right atrium. Blood that is coming from the body goes through the superior vena cava which is located on the right side of the heart, this is carrying blood from the head and other parts of the body that are above the heart and also blood comes through the inferior vena cava. Blood going through the inferior vena cava is coming from parts of the body that are lower than the heart. Has the superior vena cava and the inferior vena cava enter the right atrium which is an upper chamber, they join together, the right atrium then acts as a receiving area for the blood that is entering the heart. From the right atrium the blood goes down to the lower chamber being the right ventricle, this is done via the tricuspid valve which is a one way valve. The reason it is a one way valve is because it stops the blood going back up when the ventricle contracts. From here the blood goes through the pulmonary valve, this is done when the contraction of the ventricle takes place, the pulmonary valve is also a one way valve, it then goes into the pulmonary artery that then leads the blood to the lungs. The blood that is sent to the lungs via the right side of the heart is returned to the heart by four pulmonary veins, these take the blood to the left atrium which is the other upper chamber. The blood from the left atrium then goes through the mitral valve and down to the left ventricle, the mitral valve works in the same way as the tricuspid valve as it stops the blood going back to the left atrium and the pulmonary veins when the ventricle contracts as it is also a one way valve.
When the left ventricle contracts the blood then goes through the aortic valve, which is again one way and then goes into the aorta which is the biggest artery in the body. The aorta which curves over the top of the heart as large arteries which lead of to the head, arms and upper chest.The lower part of the aorta goes through the lower part of the chest and stomach and arteries lead off from there carrying blood into the liver, spleen, intestine, kidneys and legs. The blood then goes through smaller arteries and capillaries and it then goes back to the heart through our veins. From the aorta is also two coronary arteries, these carry blood to the heart and are a part of the systemic circulation. The blood that as gone through the capillaries in the heart then goes back into the right side of the heart through veins and sits back in the right atrium.
The cardiac cycle begins when the heart is relaxed, blood that is in the veins is at an higher pressure than the atria, therefore the means the pressure is higher than that of the ventricles, this then means that blood goes from the veins to the atria and then to the ventricles. The atria is where the contraction of the heart begins, this is also known as systole. Contraction of the atria causes the an increase in pressure which pushes more blood to the ventricles, there is then a delay of around 0.1 second, after the delay the ventricles start to contract. Has the blood pressure increases and it becomes higher in the ventricle than in the atria the tricuspid and mitral valve close, however the contraction continues causing the pressure in the ventricles to build up more than in the pulmonary artery, which then causes the opening of the arterial valve letting blood flow into the arteries. Contraction in the ventricles carry's on causing the blood pressure in the pulmonary artery and the aorta to reach it's highest point, which is the systolic blood pressure rate. After this the blood pressure then falls gradually as the blood starts moving away from the heart and to the lungs, disatole occurs when the heart relaxes and blood pressure carry's on falling.
Overall the heart is a very unique structure and is a very important part of the body, in fact it is the main functioning part of the body and without it we no longer live. There are many parts of the heart even though it is only a small organ, as it is only about the size of a fist and is the shape of a pear, and it is hard to believe that it as 60,000 miles of vessels in it.