Bibliography For Human Respiratory and Cardiac Systems

Bibliography
--------------

About.com '2004' 'Coronary Heart Disease Statistics' Available from

http://quitsmoking.about.com/ Accessed 4th May 2010

Bioen 'No Date' From Bing Images Available from http://www.bioen.utah.edu/ Accessed April 2010

Biology Reference '1998' 'Heart and Circulation' Available from http://www.biologyreference.com/

Accessed 29th March 2010

Blog Spot 'No Date' 'Artery Disease' Available from http://1.bp.blogspot.com/

Accessed May 2010

Blog Spot 'No Date' 'Smoking' Available from http://3.bp.blogspot.com/ Accessed May 2010

Burgermann '1998 - 2005' 'Arteries' Available from http://www.burgermann.info/ Accessed

29th March 2010

Cardiology Associates 'No Date' From Bing Images Available from http://www.cardiologyassociates.net/

Accessed May 2010

CDLI 'No Date' From Bing Images Available from http://www.cdli.ca/

Chest X -ray 'June 2000' 'Lung Cancer' Available from http://www.chestx-ray.com/smokers

Accessed 4th May 2010

Colorado Edu 'No Date' From Bing Images Available from http://www.colorado.edu/

Accessed May 2010

Ezine Articles 'August 28th 2006' 'The Nervous System & The Respiratory Regulation

Mechanism' Available from http://ezinearticles.com/ Accessed 29th March 2010

Faculty 'No Date' From Bing Images Available from http://www.faculty.weber.edu/

Accessed May 2020

Getwell Nature 'No Date' 'Blood' Available from http://www.getwellnatural.com/ Accessed April 2010

Goalfinder 'No Date' 'Plasma' Available from http://www.goalfinder.com/ Accessed April 2010

Heartsite '23rd August 2009' 'Heart Electrical Activity' Available from

http://www.heartsite.com/ Accessed 29th March 2010

Health Pictures 'No Date' 'Coronary Heart Disease' Available from http://health-pictures.com/

Accessed May 2010

Helium Sciences '2002 - 2010' 'The Function Of Red Blood Cells' Available from

http://www.helium.com/ Accessed 29th March 2010

How Stuff Works 'No Date' From Bing Images Available from http://www.howstuffworks.com/

Accessed May 2010

Ivy-Rose '2003 - 2010' 'The Structure and Functions Of Blood' & 'Blood Vessels' Available from

http://www.ivy-rose.co.uk/ Accessed 29th March 2010

Klb School 'No Date' From Bing Images Available from http://www.klbschool.org.uk/ Accessed May

2010

Learn SD State 'No Date' 'Red Blood Cells' Available from http://www.learn.sdstate.edu/ Accessed April

2010

Life Extension 'No Date' 'Coronary Artery Disease and Atherosclerosis' Available from

http://www.lef.org/protocols/heart_circulatory/ Accessed 4th May 2010

Medical Movement '1st Feb 2005' 'Controlling Your Blood Pressure and Cholesterol' Available

from http://www.medicalmoment.org/ Accessed 4th May 2010

News Img BBC 'No Date' 'Lungs' Available from http://newsimg.bbc.co.uk/ Accessed 4th May

2010

NHS Choices '14th October 2009' 'Lung Cancer' Available from http://www.nhs.uk/conditions

Accessed 4th May 2010

Pendleton James 'December 13th 2008' 'The Structure Of A Human Red Blood Cell'

Available from http://cellstissuesmembranes.suite101.com/ Accessed 29th March 2010

People 'No Date' 'Cardiac Output' Available from www.///people.eku.edu/ Accessed March

2010

Quit Smoking.Com '1997 - 2008' 'How Smoking Affects Your Body' Available from

http://www.quitsmoking.com/ Accessed 4th May 2010

RBCH NHS 'No Date' 'Heart Structure' Available from http://www.rbch.nhs.uk/ Accessed March 2010

Revision World 'No Date' From Bing Images Available from http://www.revisionworld.com/

Accessed May 2010

Right Health 'No Date' 'Respiratory Systems' Available from http://www.righthealth.com/

Accessed March 2010

Smart Images 'No Date' 'Heart' Available from http://www.smartimages.com/ Accessed May 2010

Smoking Lungs 'January 8th 2009' 'The Lung Cancer And Cigarette Smoking Web Page'

Avalible from http://www.smokinglungs.com/

Succeed 'No Date' 'Carbon DioxideTransport' Available from http://www.succeed.ufl/edu/

Accessed April 2010

Teach PE 'No Date' 'Transport of Oxygen' Available from http://www.teachpe.com/

Accessed April 2010

The Information Site 'No Date' 'Cholesterol' Available from http://www.theinformationsites.com/

Accessed 4th May 2010

The Respiratory Pulse Org 'No Date' 'Respiratory Systems' Available from

http://www.the-respiratory-pulse.org.ve/ Accessed March 2010

Users,rcn '23rd March 2010' 'Blood' Available from http://users.rcn.com/jkimball.ma.ultranet/

Accessed 29th March 2010

Vital Imaging 'No Date' 'Lungs' Available from http://www.vitalimaging.co.uk/lung.htm

Accessed 4th May 2010

Effects Of Smoking On The Body

6.2 Evaluate The Effects Of Smoking On Body Systems

-----------------------------------------------------



Pictures from:- http://3.bp.blogspot.com/
http://www.robertsandtravers.co.uk/

The body can be effected in many ways due to smoking, there are over 40 different chemicals in cigarettes and each is harmful in different ways. Looking at the body from top to bottom we begin at the mouth, smoking can cause mouth cancer, gum disease, tooth decay and bad breath, not to mention how the tar discolours our teeth making them yellow. Smoking also causes us to have less oxygen going around the body causing narrowing of the blood vessels to the brain which can then cause a stroke, a smoker may also suffer from a lot of headaches.

When we inhale the chemicals they travel down the chest going through the bronchi, the chemicals then attack the lining of the bronchi causing them inflammation which is what causes the smokers cough. Due to the bronchial being damaged a smoker is more likely to get infections in this area. The smokers cough can get worse by the build up of mucus in the lungs, a smoker is very likely to get lung cancer and also emphysema.

Our heart also gets severally damaged when smoking as we can get high blood pressure and there for we are more likely to get blood clots. The carbon monoxide takes oxygen away from the blood and this then causes a build up of cholesterol deposits on the artery walls, these all then add to the risk of a heart attack. There is also the risk of stroke, loss of circulation in fingers and toes and also a chance of importance.
Other parts of the body system that can be effected by smoking are the digestive system, the chemicals in the cigarettes can cause throat cancer and also oesophagus cancer, smoking also raises the amount of acid secreted therefore we are more susceptible to heart burn and ulcers, smokers also have a higher chance of getting pancreatic cancer. Many of the chemicals that are in cigarettes go out of the system through urine, this then leads to higher risk of developing bladder cancer, this is a cancer that normally is fatal, the kidneys can also be damaged due to high blood pressure.
Overall if you are a smoker you have much higher risk of developing serious illness, cancers and organ failures and you are more likely to die younger than a person who doesn't smoke.

Smoking And Lung Cancer

Picture from:- http://newsimg.bbc.co.uk



6.1b Analyse The Relationship Between Smoking
and Lung Cancer
-----------------------------------------------

This blog is looking at smoking and it's relation to lung cancer. Lung cancer is can be a primary and a secondary source, primary comes in two forms, non small cell and small cell. Non small is the one that is most common and this is responsible for on average 80% cases of lung cancer (nhs uk web). Small cell is less common and the possibility of this is the remaining 20%, this form is a more aggressive one and this usually spreads quicker. After skin cancer lung cancer is the most common one and there is around 31,000 (nhs uk) new cases discovered each year, this is in England and Wales.
Smoking it the biggest thing to cause lung cancer, in cigarettes there is more than 40 different things and the more you smoke the higher the risk you have of developing lung cancer. There is also greater risk the longer you have smoked, however after a very long period of time from stopping smoking the risk of developing lung cancer drops, when you smoke there is a 90% chance you will develop lung cancer (www.smokinglungs ).
Overall smoking really does cause our lungs a lot of damage and many sources say the same thing that the biggest cause of lung cancer is smoking, so the best way for us to afford lung cancer is not to smoke, we are also at risk of lung cancer if we are around a smoker for long periods of time, as passive smoking can be as dangerous to our health as smoking can be.

Smoking And Coronary Heart Disease

Picture from: http://health-pictures.com/

6.1a Analyse The Relationship Between Smoking
And Coronary Heart Disease
----------------------------------------------

Coronary heart disease is one of the biggest causes of death and it is the most common cause of death related to smoking. When smoking the toxins that are in cigarettes cause a build up plaque in the arteries, this then causes atherosclerosis, which is hardening of the arteries. Once the arteries harden inflammation occurs in the walls and then there is opportunity for blood clots to form which then reduce the flow of blood, which can cause heart attacks or strokes.
Coronary heart disease which can be from a result of smoking is also a result from atherosclerosis which can also be linked to smoking. High blood pressure which can also be smoking induced is also related to coronary heart disease because the heart is having to work harder to push the blood around effectively enough to keep the pressure up.
So overall smoking is linked to all major factors to do with coronary heart disease blood pressure, hardening of the arteries, heart attacks and strokes.

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

Picture from:- www.theinformationsites.com

5.2 Discuss The Relationship Between Diet, Blood Pressure,
Blood Cholesterol and Circulatory Disease
--------------------------------------------------------


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
---------------------

Pictures from:- http://1.bp.blogspot.com

www.sssibia.co

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

Picture from:- www.learn.sdstate.edu

4.2 Explain The Processes For Redistributing
Blood During Exercise
------------------------------------------


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

Picture from:- www.the-respiratory-pulse.org.ve

4.1 Explain The Mechanisms For Regulating Ventilation
and Pulse Rates
------------------------------------------------------


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

Picture from:- www.//people.eku.edu/

3.4 Calculate Cardiac Output and Discuss The
Importance Of Value
--------------------------------------------


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

Pictur from:- www.faculty.weber.edu

Pictures from:- http://www.cdle.ca/

http://www.bioen.utah.edu/

http://www.howstuffworks.com/

3.3 Explain The Electrical Activity Of The
Heart During A Heart Beat
---------------------------------------


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

Picture from:- www.rbch.nhs.uk

3.2 Describe The Structure Of The Heart and Explain
The Cardiac Cycle
-----------------------------------------------------

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.

Structure Of Arteries, Veins and Capillaries

3.1 Describe The Structure Of Arteries, Veins and Capillaries
and Relate This To Their Function
------------------------------------

Pictures from:-

www.cardiologyassociates.net

www.klbschool.org.uk

www.webanatomy.net

www.revisionworld.com

This blog is looking at the structure of the arteries,veins and capillaries and looking at each relate to their function. Our arteries contain a thick wall, the outer wall contains smooth muscle fibres. These muscle fibres contract and relax by way of instruction from the sympathetic nervous system. The inner layer of the arteries is very thin and the tissue is called endothelinal tissue.
The function of the arteries is to move blood away from the heart, they also transport oxygenated blood only, except in the case of the pulmonary artery. Has our ventricles contract, blood goes into the arteries at a high rate, this then stretches the endothelium which is folded and also the elastic walls. Once the ventricles relax it causes the elastic recoil of the wall and that keeps our blood pressure up, so it is important that the arteries are stretchy to allow this action to happen.
The veins outer part have three layers of tissue, the tissue is thinner and less elastical than the arteries layers. The veins also have valves, the valves help in returning blood to the heart, they do this by stopping it going backwards.
The function of the veins is to transport blood to the heart and to also transport deoxygenated blood only, this isn't the case with the pulmonary vein. The veins need to be stronger and thicker to enable the pressure to be kept for the valves to work and for the blood to be transported back to the heart.
Our capillaries are very small blood vessels, they are around 5 - 20 micro metres (ivy-rose web) in diameter. There is capillaries in most of our organs and body tissues. The blood that flows in the capillaries comes from arterioles and are drawn out by venules. The walls aren't very thick, this is so things like water and glucose can be broken down quickly. The venules are even smaller vessels that take blood from the capillaries and to the veins. The function of the capillaries is to supply tissue with components which are carried by the blood. It also helps to get rid of waste from cells that are around, this is beside just moving blood around the body. The capillaries also help in the exchange of oxygen, carbon dioxide, water and salt between the body tissue and the blood. With the capillaries being so small the blood flows slowly, otherwise they wouldn't be able to take the pressure and with the blood flowing slowly it enables longer time for diffusion to take place.
Overall the arteries, veins and capillaries are all different in structure but they all aid in transporting blood around the body and in getting rid of waste.