Ed Cozens

1. Ed Cozens Biology Project

2. Heart and its systems

3. Passage of blood through heart. • Blood with small or no amount of oxygen enter the right side of the heart through the superior vena cava. It travels through the right atrium through the tricuspid valve (valves ensure no backwash of blood) into the right ventricle. The right ventricle then pumps the blood through the pulmonary arteries (all arteries carry blood away from the heart) to the lungs where it receives oxygen due to gaseous exchange in the alveoli. The oxygenated blood then enters the heart via the pulmonary veins and goes into the left atrium. It passes through the mitral valve into the left ventricle which it then pumps through the aorta to the rest of the body. The oxygen is used around the body and de-oxygenated blood returns to the heart via the vena cava.

4. Waste Products • This system also disposes of waste products such as CO2. By diffusion the CO2 diffuses into the blood stream where it is taken into the lungs where, again by diffusion, it enters the air passages and is exhaled from the body. The C02 diffuses along a concentration gradient. As carbon dioxide is produced in the cells of the body its concentration increases until it is higher than the concentration of carbon dioxide in the blood stream. The net movement is therefore into the bloodstream where it is taking back to the lungs and leaves the body when through exhalation.

5. Iron deficient anaemia • Iron is used to make haemoglobin which carries oxygen in your blood (the oxygen bonds to the iron). Therefore iron is needed in red blood cells and is crucial in the transport of oxygen. If you have blood loss you will lose a lot of iron. If you have low amounts of iron the bone marrow cannot make sufficient red blood cells to transport the necessary requirements of oxygen. People with this type of anaemia have a limited oxygen supply so have symptoms such as; looking pale, feeling breathless very easily, they are constantly tired and have a higher heart rate (an attempt to get more oxygen round the body). • People with anaemia aren’t able to work as much as they tire quickly and because the heart is being over worked it can lead to heart problems. Pregnant women often feel anaemic because the baby saps the iron levels. Also if you have sustained an injury which has resulted in heavy bleeding you will feel anaemic for a period of time. One way to combat this is to have an iron rich diet (you get iron from your diet anyway) or to take iron tablets to boost your haemoglobin count.

6. Circulatory system • The main air passage is the trachea (windpipe) which consists of C shaped rings of cartilage to stop the risk of compression. From the trachea it branches off into the bronchi and bronchioles which spread out over both lungs. Finally the reach the alveoli, they have huge surface areas to allow the most diffusion possible into the bloodstream. De-oxygenated blood is pumped into the bloodstream and is carried past the alveoli so oxygen can diffuse across into it. The carbon dioxide diffuses in the opposite direction and is exhaled.

7. Chronic obstructive pulmonary disease • Oxygen is taken into the body via the air passages such as the trachea and bronchi. COPD is when the air passages are not as efficient as they should be normally because of a build-up of excess mucus; this is the case in Chronic Bronchitis which affects the bronchi. Emphysema is when the alveoli walls are damaged meaning they cannot work as efficiently. All COPD related diseases mean that less oxygen can enter the blood stream and tends to get progressively worse. It is usually caused by smoking and the symptoms include wheezing and coughing frequently.

8. Cardiac cycle • Atrial Systole • Both atria contract pushing the blood through the atrial-ventricular valves. These valves then close to stop the possible backwash of blood. • During atrial systole the pressure in the atria increase, although they are still relatively low. The pressure in the aorta stays constant, but a lot higher than the atria as it is the main blood vessel. The pressure in the ventricles increases slightly as they are filled with blood.

9. Ventricular Systole • There is a massive contraction from the two ventricles causing the blood to be pushed through the now open semi-lunar valves. The contraction starts at the apex of the heart which is why it pushes the blood upwards and out of the heart through the aorta. The pressure in the ventricles increases dramatically and is now almost equal to the pressure in the aorta which also increases due to the blood being pushed through it.

10. Diastole • The semi-lunar valves close ensuring all the blood leaves the heart. The pressure in the ventricles and the aorta start to decrease (more dramatic decrease in ventricles) as the heart is now relaxing. The blood now flows around the body in a system of blood vessels, eventually re-entering the heart via the atria. When the atria are full, atrial systole will occur and the whole cycle will repeat.

11. Valves – in depth • Atrioventricular valves • When the pressure in the ventricles drops below the pressure in the atria the valves will open allowing the blood through. As the pressure increases in the ventricles (during ventricular systole) to the point where it rises above that of the atria the blood flows upwards filling the valve pockets causing them to close blocking the passage of blood back into the atria. • Similarly with the semi-lunar valves, as the ventricles contract the pressure eventually exceeds the pressure in the major blood vessels so the valves open. When the heart relaxes the pressure drops back down below the pressure of the vessels meaning the valves close.

12. Regulation of the heart beat

13. Initiating heart beat • The heart is myogenic, meaning that it can initiate its own contraction without instructions from the brain or elsewhere within the body. • At the peak of the right atrium we find the sinoatrial node. This generates an electrical impulse, it is this impulse that triggers the heart beat. The sinoatrial node (SAN) will generate this impulse around 60-75 times a minute whilst the organism is resting.

14. Atrial Contraction • As the SAN is located near the atria the electrical impulse reaches them first resulting in the atria contracting. As the impulse travels through the atria the muscles contract. As the SAN is on top of the atria the muscle contracts in a way that the blood will be pushed downwards towards the ventricles. This occurs in the stage known as atrial systole. Between the atria and ventricles is a wall of tissue that the impulse cannot pass through. There is another node (AV node) that restarts the impulse after a tiny delay.

15. Ventricular contraction • The impulse generated by the atrio-ventricular node passes down the septum through the bundle of his. It continues downwards until it reaches the apex (bottom) of the septum at the base of the ventricles. The impulse then spreads through the ventricles in an upwards direction causing muscle contractions along the way. This is how the blood is pushed upwards into the aorta and major blood vessels.

16. Electro-cardiogram

17. Explanation of diagram • Skin sensors can detect electrical excitement of the heart muscle, this forms the graph on the ECD. • The peak at (P) is where the electrical impulse is generated and passes over the atria. The section Q,R,S is created when the ventricles are excited (ventricular systole) and T represents the resting heart (diastole)

18. Abnormalities • Irregular heart beat - arrhythmia • Elevation of the ST section indicates a heart attack • Fibrillation where the heart beat is being properly co-ordinated results in irregular peaks at P that are also uneven. • If the S wave is a much lower trough then that indicates that the ventricle wall is much thicker than it normally would be (hypertrophy). The larger trough is caused by the more powerful ventricular muscle.

19. Anna Brown symptoms • Hay fever and asthma are both allergic reactions, hay fever usually to pollen grains and asthma attacks can be brought on by dust. During allergic reactions a chemical called histamine is secreted. Histamine causes redness and itching (hay fever symptoms) or can cause the narrowing of the air tubules in your lungs making it difficult to breathe (asthma). Terfanadine is an anti-histamine which combat the symptoms. This is why terfanadine was prescribed. • The flair up of acne was probably caused by her recently changing to microgynon pills, increase in acne is a common side effect of these pills. More recently she has complained of tightness in her chest and an uneven heart-beat. These are side-effects of the erythromycin prescribed. Erythromycin have similar functions to that of penicillin.

20. Possible diagnosis • Worsened asthma and tightness of chest but no wheezing are symptoms of inflammatory asthma. Ventolin inhalers are ineffective as inflammatory asthma is an allergic reaction to things such as dust, pets even mould. • A common treatment for inflammatory asthma is advair which deals with the symptoms and combats to prevent them occurring in the first place.