Chapter 4 Biology GCSE

• The blood consists of red blood cells, white blood cells, platelets, plasma.
• The function of red blood cells is to transport oxygen from alveoli to cells all over the body
• The function of white blood cells is to fight pathogens by engulfing them
• the red pigment in red blood cells is called haemoglobin.
• Adaptations of the red blood cells: no nucleus, bio-concave shape both give it a large surface area.
• Some white blood cells produce antibodies that are Y shaped.
• Platelets are small fragments of cells that have no nucleus.
• Platelets form blood clots which go on to form scabs.
• Platelets form blood clots by turning fibrinogen into fibrin which then captures red blood cells.
• Plasma carries urea from the kidney to the bladder.
• Urea is broken down excess proteins and is a waste product.
• Arteries carry oxygenated blood away from the heart.
• Arteries have small lumin and thick muscular walls to withstand high pressure.
• Arteries have a pulse unlike veins.
• Veins carry deoxygenated blood towards the heart.
• Veina have a large lumin and thin walls for the low pressure.
• Valves prevent the backflow of blood with contraptions.
• The semi lunar valve is between the vessels and ventricle.
• The atrio ventricular valve is between the atrium and ventricles.
• Capillaries are the site of diffusion.
• Capillaries are endothelial - one cell thick
• The left ventricle wall is thicker since it needs to push blood around the whole body.
• The vena cava brings deoxygenated blood into the right atrium.
• The right atrium brings deoxygenated blood into the right ventricle
• The right ventricle takes deoxygenated blood to the pulmonary artery which takes it to the lungs.
• The pulmonary vein takes oxygenated blood into the left atrium.
• The left atrium takes the oxygenated blood to the left ventricle
• The oxygenated blood travels to the aorta and then to the rest of the body.
• Humans have a double circulatory system since it barrels around the body twice.
• Over time valves may become leaky: doctors can either provide a mechanical valve or a biological valve
• With a mechanical valve medication is needed daily to prevent blood clotting but with a biological valve it only lasts 12-15 years.
• There are a group of cells that are in your right atrium that control the heartbeat.
• If the heart pumps too quickly oxygen will not be provided properly but if it pumps too slow then it won't provide enough oxygen.
• Artificial peacemakers can be used by sending strong signals to the heart to stimulate.
• With artificial peace makers regular checkups are required.
• If a heart fails it can be given through a transplant or an artificial one.
• With artificial hearts, there's always a risk of blot clotting and death.
• Coronary heart disease is when the coronary arteries become blocked with fatty material.
• If blood flow through coronary arteries is reduced, oxygen supply is reduced too, leading to a heart attack, pain, death.
• Coronary heart disease can be treated with a stent.