Bbc bitesize cardiovascular system

If you clench your hand into a fist, this is approximately the same size as your heart. It is located in the middle of the chest and slightly towards the left.

In the heat, blood vessels close to the surface of the skin enlarge. This process is called vasodilation close vasodilation The increase in diameter of the skin arterioles to increase blood flow and increase heat loss by radiation. This allows more heat to be lost from the blood. When a person takes part in exercise their face can become pink due to vasodilation of the blood vessels close to the skin's surface. In the cold, blood vessels at the skin's surface close. This process is called vasoconstriction close vasoconstriction The narrowing of the skin arterioles to reduce blood flow and reduce heat loss by radiation.

Bbc bitesize cardiovascular system

In the heat, blood vessels close to the surface of the skin enlarge. This process is called vasodilation close vasodilation The increase in diameter of the skin arterioles to increase blood flow and increase heat loss by radiation. This allows more heat to be lost from the blood. When a person takes part in exercise their face can become pink due to vasodilation of the blood vessels close to the skin's surface. In the cold, blood vessels at the skin's surface close. This process is called vasoconstriction close vasoconstriction The narrowing of the skin arterioles to reduce blood flow and reduce heat loss by radiation. Systolic is when the heart contracts and diastolic is when the heart relaxes. The first number is the systolic value and the second number is the diastolic value. Blood pressure is determined by Q cardiac output and the resistance to the blood flow R. Resistance to blood flow is caused both by the diameter of the blood vessels and by the thickness of the blood. Furthermore, if a person has a condition called atherosclerosis plaque in the arteries , their resistance to blood flow will increase and so will blood pressure. This can have serious health implications such as causing chronic high blood pressure, angina or even heart attack or stroke. The heart's function is to pump the blood and circulate it round the body. We assess the heart's performance by measuring how much blood it pumps out each minute. This is called cardiac output.

The pulmonary artery carries deoxygenated blood away from the right ventricle to the lungs. The blood becomes oxygenated in the lungs.

An explanation of how the cardiovascular system works during exercise. In the heat, blood vessels close to the surface of the skin enlarge. This process is called vasodilation close vasodilation The increase in diameter of the skin arterioles to increase blood flow and increase heat loss by radiation. This allows more heat to be lost from the blood. When a person takes part in exercise their face can become pink due to vasodilation of the blood vessels close to the skin's surface.

Heart rate is measured in beats per minute bpm. During exercise the heart rate increases so that sufficient blood is taken to the working muscles to provide them with enough nutrients and oxygen. An increase in heart rate also allows for waste products to be removed. Stroke volume increases which means more blood is pumped out of the heart each time it contracts. At rest a person's cardiac output is approximately 5 litres per minute, while during exercise it can increase to as much as 30 litres per minute as both their heart rate and stroke volume increase. Work out the cardiac output of a person at rest with a heart rate of 70 bpm and a stroke volume of 80 ml.

Bbc bitesize cardiovascular system

All blood vessels are specifically structured to perform their function. For example, a capillary is microscopically thin to allow gases to exchange, the arteries are tough and flexible to cope with high pressure blood flow and the veins contain valves to prevent the blood from travelling backwards when at low pressure. All vessels feature varying lumen size. The lumen is the hollow opening or the space inside the blood vessel. Red blood cells are very important for sport and physical activity because they contain haemoglobin. Haemoglobin allows them to carry oxygen from the lungs to the working muscles. Red blood cells are disc-shaped cells with no nucleus. They are very small but their flattened shape gives a relatively large surface area which allows rapid diffusion of oxygen. In this guide.

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Personalise your Bitesize! The two top chambers are called atria close atria The upper chambers of the heart which pump blood to the lower chambers called ventricles. The main functions of the cardiovascular system. It is the muscular lining of the ventricles that are bigger because they have to pump the blood further than the atria. We can calculate a typical cardiac output at rest and during exercise:. The lumen is the hollow opening or the space inside the blood vessel. White blood cells which protect against disease. Blood vessel Renal vein Function Carries deoxygenated blood also low in urea as it has been purified in the kidney back to the heart. This allows more heat to be lost from the blood. More guides on this topic. The effect of asthma, smoking and exercise on the gas exchange system. These are small blood vessels that branch off the aorta and can be seen on the external surface of the heart. This can have serious health implications such as causing chronic high blood pressure, angina or even heart attack or stroke. Carries digested food glucose and amino acids from the liver around the body. Aorta Carries oxygenated blood from the heart around the body.

The first number is the systolic value and the second number is the diastolic value.

This is called systemic circulation. Activity 3: Create a booklet. Blood pressure is determined by Q cardiac output and the resistance to the blood flow R. And your white blood cells are like police looking for germs. This unidirectional flow of blood through the heart shows that mammals have a double circulatory system. Next page. Delivery needed! Hepatic artery Carries oxygenated blood to the liver. In this guide. I need oxygen! You feel this when you feel your pulse. Next page. Require immediate backup!