Explain the transportation of oxygen and carbon dioxide in the blood.

Oxygen is transported in the blood by (RBC). It binds with a substance in red blood cells called haemoglobin. Haemoglobin is made up of iron and simple proteins.
When oxygen and haemoglobin bind it is called oxyhaemoglobin. When the red blood cells reach cells in the body where oxygen is needed the process of binding is reversed and the oxygen diffuses into the cells once again leaving haemoglobin in the (RBC).
The waste product from the cells is called carbon dioxide. This diffuses into the (RBC) and it makes carbonic acid by combining with the water. This process is made faster by an enzyme called 'carbonic hydrase'

Ref:-www.miracleofthebloodandheart.com/4_dif_image006_0000.jpg

Edited by Parsons.R,Undated,GCSE Double Science Biology The Revision Guide Higher Level,Newcastle upon Tyne,Coordination Group Publications LTD.

CGP Class handouts.

Describe the structure of a red blood cell and explain how this relates to its function.

Red blood cells (RBC) are bio-concave in shape to give maximum surface area for the absorption of oxygen. They contain haemoglobin which when combined with oxygen makes oxyhaemoglobin which is what gives blood its bright red colour.
(RBC) have no nucleus to make more room for Haemoglobin.
(RBC) are very small. They are only 1/25,ooo of an inch big. They are also very flexible to enable them to squeeze there way through small spaces.
A(RBC) has a life span of aprox 120 days and then it is destroyed by the phagocyte cells. Old cells that are destroyed are constantly replaced by new (RBC) made in the bone marrow.

Ref:-Image from http://www.fi.edu/learn/heart/blood/images/red-blood-cells.jpg

CGP Handouts.

Describe the components of plasma and explain their functions.

Plasma is made up of mainly water, but it also carries Red blood cells, white blood cells, platelets, carbon dioxide, urea, hormones, antibody's and antitoxins and nutrients such as amino acids and glucose.

Red blood cells.

These carry oxygen from the lungs to all the cells in the body, in the form of oxyheamoglobin. They also carry carbon dioxide back to the lungs from the cells to be expirated.

White blood cells.

White blood cells defend the body against disease. They do this by consuming bad micro organisms and by producing anti body's that fight bacteria and anti toxins that neutralise toxins that bacteria have secreted into the body.

Platelets.

Platelets are very small bits of cells. They float around in plasma and are needed to help the blood clot and form a scab which stops the loss of blood and prevents infections from entering the body.

Urea.

Urea is secreted by the liver and is excreted in small amounts in sweat and also in urine.

Hormones.

Hormones are 'chemical messengers' that are carried in the blood. They are produced by the endocrine glands and only have an effect on target cells.

Nutrients.

These are needed by the body to repair it and to provide energy.

Some substances dissolve into the water in the blood and are carried in 'solution' and some do not dissolve and are carried in 'suspension'.

Ref:-Image from http://www.media-2.web.britannica.com.leb-media/71/91871-034-DA6BAO42.jpg

CGP Handouts

Edited by:-Parsons.R,Undated,GCSE Double Science Biology The Revision Guide Higher Level,Newcastle upon tyne, Coordination Group Publications LTD.

Describe the role of the nervous system in generating breathing rhythm.

Nerve impulses are passed from the brain down the brain stem and along the spinal nerves to the diaphragm and intercostal muscles. This causes the contraction and relaxation of the diaphragm and intercostal muscles during breathing.

The area of the brain that these spinal nerves carry impulses from is called the 'Medulla oblongata' also known as the Respiratory centers. The Respiratory is connected to a second Respiratory center in the 'Pons'.

The two respiratory centers allow for automatic breathing.

The respiratory centers can be over ridden by a part of the brain called the 'cerebella cortex'. This allows for us to control our breathing rate and hold our breath, all thoe this control can only be exerted for a short time at which point the medulla oblongata and the pons would override the cerebella cortex and automatic breathing would begin again.

The pons control the standard rate of breathing but it is also connected to the medulla and sensors that detect oxygen and carbon dioxide in the blood to allow for the breathing rate to change.

Ref:-Image from http://www.media-2.web.britannica.com/eb-media/71/91871-034-DA6BA042.jpg

Evaluate the conditions necessary for effective gaseous exchange.

There needs to be many alvoli in the lungs to provide a large surface area so that maximum gaseous exchange can take place.

The oxygen moves from the alveoli into the capillaries and carbon dioxide moves from the capillaries into the alviolis. This process is called diffusion. For diffusion to take place the walls of the alveoli and the capillaries are only 1 cell thick.

Inspiration (breathing in) and expiration(breathing out) is controlled by a part of the brain called the medulla.

Damage or disease to this part of the brain or any part of the airway can result in inadequate gaseous exchange.

Ref:-Image from http//:www.image.tutorvista.com/content/respiration/alveolus-of-man.jpeg

Describe the structure of the respiatory system and relate this to the process of ventilation.

The Nasal Passages.

Are two passages made up of cartilage through which the air is drawn into the body. They contain Goblet cells which produce mucus and cilia cells which keep the mucus moving. Mucus traps and prevents infections from entering the body. The nasal passages also moisten and warm air before it enters the Pharynx.

Pharynx.

This is the space behind the nasal cavity and above the Larynx.

Epiglottis.

Small flap of tissue that covers the trachea during swallowing to prevent foreign objects from entering and causing choking.

Larynx.

Also known as the voice box. It has two membranes and air passes through causing the vocal cords to vibrate and produce sound.

Trachea.

The Trachea is the airway also known as the windpipe. It is kept open by the rings of cartilage in its walls and allows the air to pass into the lungs.

Bronchi.

The Trachea splits into two tubes called Bronchi.

Bronchioles.

This is where the Bronchi branch off into smaller and more extensive tubes inside the lungs.

Alveoli.

Many small sacks at the end of the Bronchioles where gaseous exchange takes place. The walls of the Alveoli are only 1 cell thick to allow for the diffusion of oxygen and carbon dioxide and are numerous to provide greater surface area for gaseous exchange.

Lungs.

Located on either side of the heart. The right Lung has 3 sections and the left only 2. This enables room for the heart to sit in a space known as the cardiac notch. They are surrounded by a pleural membrane and in between is a pleural fluid that both protect the lungs from friction.

Ref:- Image from www.andrewparisi.com/tobacco/images/respiratorysystem.jpg

Evaluate the effects of smoking on body systems.

Nicotine is not carcinogenic but is toxic and in high doses can be lethal. Damage caused to the body is :-

• Lung diseases-chronic obstructive pulmonary disease, including corany heart disease, heart attacks and strokes are higher in smokers.
• Nicotine causes constriction of blood vessels resulting in high blood pressure and raising the heart rate.
• Smokers blood becomes thicker and stickier which puts extra stress on the heart and causes damage to the inside of blood vessels, which may lead to atheroma.
• Poor circulation to the extremities (hands and feet) can cause neuropathy.
• Smoking damages the mouth, teeth, gums and may cause ulcers of the digestive system.
• Osteoporosis caused by leeching of calcium from the bones leaves smokers more prone to fractures and Avascular Necrosis.
• Hydrogen cyanide damages the cilia in the respiratory tract and harmful chemicals can then collect in the lungs, stopping effective oxygenation of blood in the lungs.
• Carbon oxide binds with haemoglobin before oxygen. So because less oxygen is carried in the blood, more stress is put on the heart to pump blood around the body faster to deliver much needed oxygen.
• Tars can cause cancer of the throat and oesophagus .
• It causes the stomach to increase its secretion of acid which can cause heartburn and stomach ulcers.
• Bladder cancer can be caused by carcinogenic chemicals present in urine.
• High blood pressure causes damage to kidneys.
• Women's fertility can be lowered and an increase in cervical cancer.
• Men may suffer a low sperm count , abnormal sperm, low sperm mobility and decreased sex hormones. Decreased circulation may cause impotence.
• Immune system is impaired, making it harder for the body to fight infection.
• Skin becomes dry causing premature ageing.
• Miscarriage is more common in women who smoke.
• Smoking while pregnant or around children increases the risk of low birth weight, premature births, cleft lip palate, infections and Sudden Infant Death Syndrome (SIDS)

Looking at the risks above the amount of health risks associated with smoking far outweighs the reasons not to quit.

Ref:- Image from www.topnews.in/health/files/smoking-cigarette.jpg

www.free-online-health.com/smoking-health.htm (accessed 03/05/2010)

Analyse the relationship between smoking and coronary heart disease and lung cancer.

Cardiovascular diseases affect the heart and arteries causing ill health and is also the leading cause of death in the u.k. An estimated 198,000 people are dying every year in the u.k of (CVD). (CVD) links to smoking include:- High blood pressure, Coronary heart disease, Angina, Atherosclerosis, Heart failure and Heart attacks.




Cerebrovascular diseases affect the flow of blood to the brain and is the third largest cause of death in the u.k , they include 'Dementia' and 'strokes'. In England 111,000 people have strokes every year.

Smoking is thought to be the cause of 85-90% of lung cancer and is the leading cause of cancer related deaths. In 2007, there were 29,660 deaths in England and Wales.

Social smoking ( only smoking on occasions) still increases the risk of coronary heart disease and cancer-30% more than none smokers.

Research has shown that smoking 4 joints (tobacco mixed with marijuana) may cause as much damage as 20 cigarettes.

Second hand or passive smoke contains 4,000 chemicals and of those 69 of them are carcinogenic. Passive smoking carries the increased risk of lung cancer (24%) and heart disease(25%). It also gives a higher chance of blood clots due to the blood becoming sticky.

Ref:-Image from www.scandirectory.com/blog/smoking_Heartdisease_Scan_Blog_June09.jpg&imgrefur

www.nhs.uk/conditions/smoking-(quitting)/pages/risks.aspx ( last reviewed 13/04/10) (accessed on 03/05/2010)

www.nsh.uk/chq/pages/2289.aspx?categoryid=53&subcategoryid=536 (last reviewed 29/11/2007) (accessed 03/05/2010)

Discuss the relationship between diet, blood pressure, blood cholesterol and circulatory disease.

Too much fat in the diet can cause fatty build ups of plaque in the arteries called Atheroma. The more blocked an artery is the less space there is for blood to flow through it , resulting in higher blood pressure, as the heart has to work harder to circulate the blood and at the same time highers the stress on itself.

An important part of reducing cholesterol in the blood is eating a healthy diet, this includes eating less saturated fats and trans fats, eating more fruit and veg, whole grains and fibres,drinking less alcohol and reducing salt intake.

Trans fats naturally occur in meat and dairy products. They can be found in many processed foods and sweets and have the same effects on the body as saturated fats.

However, there are fats that the heart needs to stay healthy. These are mono and poly-unsaturated fats which are found in fish oils and plants. By lowering triglycerides in the blood, they lower the risk of cardio vascular disease (CVD) by reducing blood clotting and regulating the heart rhythm.

Some plant derived compounds-'stanol' or 'sterol esters' have been shown to reduce cholesterol levels. They can be found in some drinks, yoghurt's, spreads and soya(dairy alternative).

A person should try to consume 5 portions of fruit and veg a day. They contain essential nutrients eg: vitamins C and E and carotenoids.(organic pigments). They could help protect the body from (CVD) by limiting the damage done to the blood vessels by cholesterol.

Research has shown that wholegrain foods can reduce the risk of (CVD) by up to 30% . While Fibre lowers LDL cholesterol.

High intakes of alcohol results in higher risk of clots forming in the blood. However 1-2 units of alcohol a day has been found to reduce the risk of (CVT). Saving all the units up and then binge drinking does not give the same benefits.

Soya protein is a good substitute for meat and 25g+ a day has shown a reduction in LDL cholesterol and (CVD). It inhibits the growth of cells that form artery clogging plaque.

Ref: Image from www.kidneydiettips.dowitablogs.com/up-content/uploads/2008/10/istock_000006148437-heart.jpg

www.bbc.co.uk/health/treatments/healthy-living/nutrition/dietary_cvd.shtml
(reviewed in July 2008 by MRC Human Nutrition Research. (accessed 03/05/2010)

Describe the changes in artery structure associated with circulatory disease.

Atheroma (plaque) is the main cause of cardiovascular disease such as heart attacks, strokes and angina.It is also referred to as atherosclerosis and hardening of the arteries.

It is a build up of fatty deposits inside the lumen of the artery. If left untreated Atheroma can build up over time and partially or fully block arteries resulting in ill health and death.

Sometimes a minute crack on the inside wall of the blood vessel can cause a blood clot to form over the Atheroma, and this may block the artery completely.

Ref:Image from www.texasheat.org/HIC/Topics/Cond/pud.Cfm

www.patient.co.uk/health/Atheroma.htm (Last reviewed 15/04/2010) (accessed 02/05/2010)

Eplain the process for redistributing blood during exercise.

When the body is at rest aprox 15% of blood is supplied to the muscles and the rest goes to the organs.
When the body starts exercising this per cent age can increase to 80-85% and less blood goes to the organs all thoe the amount of blood that goes to the brain stays the same.

Blood being redistributed around the body is called the 'vascular shunt mechanism'

During light exercise redirection of blood to the skin enables the body to get rid of heat and keep cool. Skeletal muscle arterioles and pre-capillary sphincters vasodilate, increasing blood flow to muscles being used and organ arterioles and pre-capillary sphinchters vasoconstrict, temporally reducing blood flow to the organs.


Ref: Image from www.brainbasedbusiness.com/uploads/brainexercise-thumbjpg

www.webcache.googleusercontent.com/search?g=cache:12brQbSNO-UJ:www.school-portal.co.uk/GroupDownloadfile.asp%3FGroup (Accessed 02/05/2010)

Explain the mechanisms for regulating ventilation and pulse rates.

Ventilation and pulse rates are controlled by the nervous system . The nervous system consists of the brain and the spinal cord. Electrical impulses are transmitted around the body by neurones to enable the body to deal with certain situations.There are two sides to the nervous system known as the sympathetic nervous system(which speeds things up) and the parasympathetic nervous system(which slows things down).

This process can be seen during times of fear and stress, and is often referred to as 'Fight or Flight'.This means that when the brain senses danger, the sympathetic nervous system, will send electrical impulses down the spinal cord and along neurones which will : Dilate the pupils (for better vision) , inhibit saliva flow, Dilate the bronchi (to allow for maximum amount of oxygen to enter the body), inhibit peristalsis and secretion, Convert glycogen to glucose, secrete adrenaline (which increases heart rate and breathing) and inhibits bladder contraction.

When the danger has passed then the para-sympathetic nervous system takes over and all the reactions above return to normal.

Ref: Image from www.drstandley.com/images/nervous5.bmp

Calculate Cardiac output and discuss the importance of this valve.

The' Cardiac output' (CO)is the amount of blood pumped per minute by the heart. In men this is aprox 5 lpm and in a woman it is aprox 4.5 lpm.

The' Pulse'(HR) is a way of measuring the number of cardiac cycles per minute. It normally ranges between 60-80 bpm.

The' Blood pressure' is the intensity of the blood when it leaves the heart eg: 120/80.

The 'Stroke volume' is the amount of blood per heart beat.

Measurement of the cardiac out-put is important as a change in the (CO) may indicate a change in health. Each (CO) would be assessed on the individual and their circumstances.

Ref: image from www.familydoctor.co.uk/media/upload/Table%20cardiac%20output.jpg

Access to HE class tutorial.

Explain the electrical activity of the heart during a heart beat.

The heart is stimulated by the 'Sympathetic' and 'Para-sympathetic' nervous system. The Sympathetic nervous system speeds the heart up while the Para-sympathetic nervous system slows it down.
The heart has its own electrical pace maker that is in the upper part of the Right atrium(RA). It is a collection of electrical fibres that are highly specialised called the 'Sino-Atrial (SA) node.

The (SA) node creates a number of sparks per minute but this can be increased during exercise or illness and lowered during rest and when a person is very fit.

The (SA) node fires an electrical impulse which causes the Right atrium to contract. This is called A 'P' wave on an electrocardiogram (ECG). The electrical impulses then move to the ' Atrio-ventricular' node (AV) node where it pauses very briefly to allow blood to finish emptying from the Atrium into the Ventricle. This pause is called the 'PR interval' on a ECG. Next the eletrical impulses travel through the Left and Right Bundle Branches, also know as 'His fibres' and 'Purkinje fibres'. This makes them contract and blood is pumped into the Pulmonary artery and the Aorta. On an electrocardiogram this is called the 'QRS complex'. As the Ventricles recover it produces a 'ST segment' and a 'T wave' on the ECG. Ref: Image from@www.sites.google.com/site/ehgprojectgmu/

Dr. Abdulla.M @ www.heartsite.com/html/eletrical_activity.html. Last reviewed 04/04/2010. Accessed 14/04/2010.

Describe the structure of the heart and explain the cardiac cycle.

The heart is made up of cardiac muscle. The left side of the heart that deals with pumping out oxygenated blood has thicker walls than the right side which deals with de-oxygenated blood.

It has four chambers called the 'right atrium'(RA),' right ventricle'(RV), 'left ventricle'(LV), and the 'left atrium'(LA).

The (RA) and the (RV) are connected by a valve called the'Tricuspid'valve. The (LA) and the (LV) are connected by the 'Bicuspid' valve also referred to as the 'Mitral' valve. The valves are present to prevent back-flow of blood.

The heart also has two arteries and two veins by which blood enters and exits the heart. These are the'Vena cava' the 'Aorta' the 'Pulmonary artery' and the 'Pulmonary vein'.

De-oxygenated blood enters the (RA) via the Vena cava where it is pumped down through the Tricuspid valve into the (RV). From here it is pumped up through another valve called the 'Pulmonary valve' and out towards the lungs in the Pulmonary artery.

Once the blood has been oxygenated by gaseous exchange n the capillaries around the lungs, it is transported back to the heart. It enters the heart through the Pulmonary vein into the (LA). It is then pumped through the Bicuspid valve, down into the (LV). From here it is pumped up through a valve called the 'Aortic valve' and is carried out of the heart via the Aorta to the cells in the body needing oxygen. When the oxygen from the blood has been used it transports back to the (RA) where the process begins again.

The pumping of the blood through the Heart and around the circulatory system is caused by the contraction (systol) and the relaxation (diastol) of the atrium and the ventricles which is stimulated by electrical impulses from a group of electrical cells within the wall of the (RA) called the 'Sino-Atrial (SA) node.

Ref: Image from www.rbch.nhs.uk/images/dorset_health_centre/heart_diagram.jpg&imgrefrl%3Dstructure%2Bof%2Bthe%2Bheart%2Bdiagram%2um%3D1%26hl%3Den%26sa%3DN%26rlz%3DIRZADFAenGB356%3Disch:1

Describe the structure of the arteries, veins and capillaries and relate this to their function.

An artery is made up of elastic fibers, smooth muscle and a membrane called an 'Endothelium'. There is a hole running through the center of the artery called the 'Lumen'. Artery walls need to be thick and stretchy, this is because they carry oxygenated blood at a high pressure from the heart.

A vein is also made up of elastic fibers and smooth muscle and also has an Endothelium. Veins differ from Ateries because their walls are much thinner, as the deoxygenated blood they carry is at a lower pressure. The lumen in a vein is bigger than that of an artery to allow blood to flow though it with ease. Veins also contain valves to make sure that the blood continues to flow in the right direction.

Capillaries are very small and is made up of an Endothelium that is only 1 cell thick. This allows for food, oxygen and carbon dioxide to move through the walls by diffusion.

Ref: Image from www.hcc.uce.ac.uk/physiology/images/arteries%2520

Edited by Parsons R,Undated,Double Science Biology The Revision Guide Higher Level,Newcastle upon tyne,Coordination Group Publications Ltd.