9 transport in animals

• The circulatory system is a system of blood vessels with a pump and valves to ensure the one-way flow of blood.
• Blood carries oxygen, nutrients, hormones, waste products, and immune cells around the body.
• Veins return blood back to the heart at low pressure.
• Capillaries are tiny blood vessels that allow exchange between the blood and tissues.
• Valves prevent backward flow of blood in veins.
• The heart has four chambers - two atria (receiving chambers) and two ventricles (pumping chambers).
• Arteries carry blood away from the heart at high pressure.
• Fish have a single circulation system
• Blood flows through? (fish)


  gill circulation and system circulation that shares one heart
• What is the disadvantage of single circulation?


  the pressure drops in capillaries and the blood flow to the body tissue is slow, which limits metabolic rate
• Mammals have a double circulation system
• Oxygenated blood is pumped from the left to the tissues where it loses most of its pressure
• Deoxygenated blood returns to the right side where it is the pumped to the lungs to be oxygenated
• The oxygenated blood is sent to the left side to be pumped to the tissues
• what is the advantage of double circulation system?


  pressure is increased after the blood has passed through the capillaries of the lungs
• structure that separates oxygenated and deoxygenated blood

  Septum
• Structure that prevents the back flow of blood from ventricle to atrium

  AV valve (atrioventricular)
• Blood vessel that carries oxygenated blood

  Aorta
• structure that prevents back flow of blood from pulmonary artery to right ventricle

  tricuspid valve
• what is meant by a double circulatory system 


  The blood passes through the heart twice during one circuit of the body
• Passage of blood through the heart


  Walls of atria contract, pressure causes AV valves to open, blood from atria empties into the ventricles, walls of atria relax, walls of ventricles contract, pressure causes AV valves to snap shut + semi-lunar valves open, blood leaves the left ventricle via the aortic valve and the right ventricle via the pulmonary valve
• Why does the heart rate increase during exercise


  The muscles need more oxygen from the blood to carry out respiration so the heart has to pump it harder
• What is Coronary heart disease (CHD)


  When the coronary arteries are blocked by build up of fatty plaques. It restricts the blood flow.
• The coronary artery supplies the heart
• Risk factors of CHD?


  Smoking, high blood pressure, high cholesterol, diabetes, obesity, and family history.
• How to reduce risk of CHD?


  Eat healthy, be more physically active, healthy weight, don’t smoke, reduce alcohol consumption, keep blood pressure under control.
• vein structure 


  Large lumen, often have valves, relatively thin walls
• Arteries structure


  Thick layer of muscle and elastic fibres, small lumen, thick walls.
• Capillary structure


  Walls are a single cell thick, tiny vessel with narrow lumen.
• What is a murmur?


  A murmur is a blowing, whooshing, or rasping sound that occurs during a heartbeat
• causes Of abnormal murmur?


  Usually causes by problems with the valves that separate the chambers of the heart
• Murmurs can be caused by heart problems that range from mild and requiring little or no medical intervention to life threatening, requiring immediate surgery
• the ECG is a diagnostic tool that measures and records the electrical activity of the heart
• The results of an ECG will determine what treatment is given, if any
• Some of the various heart problems that can be diagnosed by ECG include, abnormal rhythm or irregular heart beats and damage to the heart, such as when one of the coronary arteries is blocked
• ECG stands for


  Electrocardiogram