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Biology - Topic 3 - The Cirlulatory System + Lungs

Red Blood Cells

• Disc like cells with no nucleus.
• Transport oxygen, haemoglobin loads the oxygen in the lungs.
• Made in the bone narrow. Limited life span, destroyed in the spleen.
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• Legenda: Red blood cell

Slide 3

• Platelets - Smallest cells - release chemicals to make blood clot when we cut ourselves.
• Plasma - Liquid part of blood, carries blood cells around the body.
• Phagocyte - Much larger cells, engulfs bacteria.
• Lymphocytes - Same size as red blood cells, produce antibiotics to destroy microorganisms.

Blood pipes

• Arteries - Carry blood from heart to organs - pumped out by the ventricles, puts pressure on walls and has the ability to recoil.
• Veins - Carry blood from organs to the heart, puts little pressure on walls, able to allow blood to pass in right direction.
• Capillaries - Carry blood through organs. Capillaries must be small to fit between cells.

The Heart

• The heart is made out of cardiac muscle - a double pump that squeezes blood around the body and to lungs. (The left side)
• The right side pumps blood around to rest of body.
• It contracts then has a short rest every cycle. Beats up to 60 times per minute without fatigue (cramp) and is supported with oxygen and food by coronary arteries.
• Ventricle muscle: sends blood further, contracts longer and is thicker.
• Left ventricle: Larger volume than right ventricle to create more pressure.
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• Legenda: Heart in the body

Slide 6

• Atrial Systole: Both atria contract high blood pressure in atria causes bicuspid and tricuspid valves to open. Blood is forced into ventricles.
• Ventricle Systole: Both ventricles contract. Bicuspid valves close to prevent backflow. High blood pressure in ventricles causes semi - lunar valves to open. Blood is forced out.
• Diastole: Both atria and ventricles relax. Blood enters chambers of heart. Semi - lunar valves close.

The Lungs

• Trachea and Bronchus: The main breathing tubes, held open by rings of cartilog.
• Alveoli: Site of gas exchange, tiny air sacs and good blood supply.
• Bronchioles: Smaller breathing tubes, keep dividing to take air to parts of the lungs.
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• Legenda: Lungs